in the last class we started discussing to find out if we can predict whether a metal will undergo corrosion or not. We will continue that one to make this concept clear. Before we do this, I like to summarize what we discussed in the last class. We said that for any reaction be it a corrosion or be it a chemical reaction or a physical transformation the first criteria for the spontaneity the reaction to occur spontaneous the corrosion is the free energy change. The free energy change delta G has to be negative this is what we saw in the last class. But if you talk about a corrosion measuring the free energy change is more difficult for every corrosion processes. So, what we did? We looked at the corrosion processes especially the aquas corrosion processes in detail. We said that the electrochemical corrosion the electrochemical reaction is the basis for aquas corrosion right. You may take for example, zinc reacting with hydrochloric acid giving rise to zinc chloride and plus the hydrogen gas. This may look like a simple chemical reaction, but in a sense e is an electrochemical reaction right. If you recollect we said that you can write this as zinc interacting with 2 plus ions in the solution and then zinc is getting oxidized and the hydrogen ions are getting reduced to form this. So, there is an oxidation process there is a reduction process. So, you can separate this into zinc going as zinc 2 plus plus 2 electrons and 2 H plus plus 2 electron giving as the hydrogen process and we call this an oxidation and we call this as reduction process. So, if you assume that that this is in a electrochemical process, we go for electrochemical criteria. It is easy to measure the potential of in electrochemical systems. How do you measure this potentials? How do you relate it to the free energy change? We also saw that we use the Nernst relationship. What is the Nernst relationship? It is between the free energy change delta g is related to minus n f e is what we saw in the last class. So, you can relate the free energy change to the potential using this the Nernst relationship right. Now, for a chemical reaction you have a relationship delta g is equal to delta g naught plus RT ln activity of the products upon the activity of reactants you saw that right. For any reaction we can write like this and using the equation 1 into 2 do this you can convert this into E equal to E naught minus RT by n f ln activity of the product upon the activity of the reactants. And this is the the Nernst equation right. This is the Nernst equation. How do you read this equation? Let us take the example given here zinc right. Let me look at zinc immersed in in zinc ions right. This immersed in zinc ions right this is the zinc metal the solution. It establishes in equilibrium right wherein zinc goes as zinc 2 plus and again it comes back. In the process the electrons are getting exchanged between zinc ions and the zinc metals. The potential is so established between the zinc and the solution containing zinc ion we call them as in equilibrium potentials right. And this potential E is called as what is called as equilibrium potentials. Please understand it is neither oxidation nor reduction right. The reaction occurs forward the reaction occurs backward. So, you cannot call this potential as either an oxidation potential we do not call either as a reduction potential we call them as what? We call them as equilibrium potentials. This is a very important thing in understanding the electrochemical equilibrium. So, what I mean by that if I write an equilibrium in this manner or you write like this both of them would exhibit what? Both of them would exhibit same potential irrespective of what? Irrespective of the way you write it. So, the potential is sign invariant we saw this in the last class. So, how do I get the equilibrium potential? What is the criteria for that? Can anybody recollect? How do I get the equilibrium potential? If I give you a concentration of zinc let us say 0.1 molar suppose I give 0.1 molar I substitute in the equation right. But equation will be always written in such a way that E is equal to ok E naught plus 40 by N f L n activity of oxidants upon reactivity of reductants. So, only when you write like that you will get V value correctly otherwise E value could be changing ok. So, this is the the most important thing in determining the equilibrium potential for any electrochemical system. We discussed this in detail in the last class right and if you have any questions on this no questions. So, let me proceed now. Now, let us go into this the next equation right like we have seen E is equal to E naught plus 2.303 RT by N f and log of the activity of oxidants upon the activity of reductants. You know what R is right? R is what? R equal to the gas constant which is equal to 8.314 joules per mole K per Kelvin joule or kilo joule joule it is a joule it is ok. You can also see you can represent as kilo calories and T is is a temperature in in Kelvin right. What is F? F is equal to Faraday constant is given as roughly 96500 coulombs. If temperature is assumed to be is equal to 25 degree Celsius I have 270 convert that into it what happens is equal to 298 Kelvin then you substitute everything in this here 2.0303 RT by F. So, 2.303 RT by F turns out to be 0.059. You can calculate this at leisure time and you see that the number that is given is the correct number or not. So, now, using this you should be in a position to calculate the equilibrium potential for any electrochemical system right be it Fe 2 plus E is in equilibrium with Fe 3 plus zinc is in equilibrium with zinc 2 plus ions no matter what the equilibrium is you should be in a position to determine clearly what the equilibrium potential is in calculation. How to measure this? How do you measure this? How do you measure this? Is it a measurable quantity or I say no no it can be only calculated can you measure this? Right. So, I should be able to measure this. We have seen in the last class again that it is not possible to measure the absolute value right. If you are going to use another probe in the in the electrolyte for example, if I consider an electrochemical system some metal take for simplicity same zinc is in equilibrium with zinc ions where to measure it I need what? I need a probe. If a moment I put a probe here and I measure with the volt meter and this probe also will have an equilibrium. So, you are going to measure only a potential difference you cannot actually measure the absolute values it is not possible right. So, how does one solve the problem? The problem is solved by considering this equilibrium H plus plus 2 electron giving rise to hydrogen in the standard state. You consider E for that is considered as a. So, we consider that as a 0 and all the potentials measured are in relation to hydrogen right. So, in relation to hydrogen that you can measure it. So, you need an electrode you need an electrode which is also in equilibrium. So, how do you visualize this? Can somebody visualize an experiment measurement of equilibrium potential yeah yourself. So, let us say I want to measure the electrochemical potential of ion immersed in Fe 2 plus ions. What do you do? I take a beaker I put Fe 2 plus ions of the given concentration I dip ion electrode and other side what I will have? I will have an hydrogen electrode. The hydrogen electrode in what state? The standard state. What is the standard state? The activity of H plus ions equal to unity the hydrogen partial pressure is equal to one atmosphere and I use a voltmeter. What is that voltmeter? An high impedance voltmeter the measured potential between these two are called as the equilibrium potential of the ion Fe 2 plus system very simple. But in practice if I have to I have to measure the potential by use a hydrogen electrode it is very complicated. Why it is complicated? What is the hydrogen electrode? I will just define to you what hydrogen electrode is ok. I would say you would have some beaker made up of let us say glass I immerse a platinum electrode here right. And then what I do? I take acid let us say hydrochloric acid where in the activity of H plus is equal to 1 I pass through this hydrogen gas. What should be partial pressure of hydrogen here? The partial pressure of hydrogen here has to be the potential so measured equal to standard potentials. If I have to do this in the lab it is very cumbersome not very easy right. Can you do this very easily? Not very easy. So, you are going to use reference electrode which are easily can be made very easily. And these reference electrodes are what? They are all some of them called as Kalamal electrode ok. And you can also have silver silver chloride electrodes. You can also have copper copper sulphate electrode. There are several of them are there right. What is the Kalamal electrode? It consists of mercury and macros chloride like this. And these electrodes have potentials depending upon the concentration in this case concentration of chloride concentration of chloride here. And if you are going to use a saturated Kalamal electrode saturated Kalamal electrode ok. The potential is plus 0.2444 volts with respect to standard hydrogen electrode. Similarly, you can also have silver silver chloride and the chloride is saturated. Then the potential is is equal to plus 0.197 volt ok. I just give an example and there are several electrodes you should refer this in standard books ok. In fact, there is a book on reference electrodes only. How to make this reference electrode in the in the lab? You can you can construct this things yourself only. So, these values you can obtain from any books in a standard books. So, there is no problem ok. So, far I suppose you are clear about how do you calculate a reference? I am sorry how do you calculate equilibrium potentials? You know how to measure the equilibrium potential of the systems ok. Then how do you use this potential to predict if the corrosion occurs or not? That is given by this concept what is called as E cell is is equal to what? E cathode minus E anode here right. This is for the cathode and this is for the anode and by convention this has to be always positive. It cannot be negative at all it has to be only positive right. So, use this criteria. So, this is the criteria this is the criteria. Now, what is the corrosion? In corrosion you have two reactions one is oxidation we call as anodic and other is a reduction which is what which is the only thing is we do not know which will be cathode and it will be anode that we do not know. Now, let us take this example and see how this can be used to predict if the corrosion occurs or not. I have given you a handout ok. Please take this handout. What is given there? What is given is the standard oxidation reduction potentials. It is also called redox potentials. I would simply call it as standard potentials. What is the standard potential? Yeah. So, let us go back to this equation. To go back to this equation what you have seen before you go back to this equation here right. Let us take this equation one of this you take this equation here. When the activity of the of the the reductant the activity of the oxidant or or you can take this equation the activity of oxidant and reductant they are unity the equilibrium potential equal to standard potentials. Please remember this. So, it is a special case of the equilibrium potential right is it is essentially equilibrium potential the special case of the equilibrium potential right that I think is is what we should do. So, what I shown here take this table ok. Now, in the table let us take two cases take the case of say copper take the case of let us say iron 2 and I am going to take copper and I am going to immerse in sulfuric acid. So, I am also going to take iron and immerse in sulfuric acid ok. So, two cases iron in one normal sulfuric acid ok and copper in one normal sulfuric acid. Some of you who are not familiar with this normality, molarity I think you should read and maybe discuss with yourself and it will be hard for me to to discuss here actually ok. So, please get yourself familiarized with the with these units of concentrations how do you really represent them actually ok. Just take two cases. So, I am going to have put it in this form of a diagram take here I am going to immerse copper here one normal sulfuric acid and I am going to have iron in one normal sulfuric acid. Please notice they are de-erated de-erated means these are all de-erated no dissolved oxygen present in both the cases. Now, we need to predict if the corrosion occurs. I make your life more simpler for you I will say that the partial pressure of hydrogen here is equal to 1 atmosphere and the partial pressure of hydrogen here equal to 1 atmosphere I make it quite simple. Now, you tell me how do we really solve the problem? Let us take this the table where you have standard potentials given for the host of equilibrium and iron and copper equilibrium also given in this. Please tell me how do we solve this problem? So, what you have to do first of all first of all you have to write the corrosion equation right. What will be the corrosion equation in both the cases? Let us say in the case of iron what will be the corrosion equation? What do you think happens? If you put iron in in sulfuric acid what do you think will happen? With corrodes what ox what oxidizes? Iron will oxidize. Iron will oxidize as Fe 2 plus and hydrogen will as if if iron corrodes. Similarly, what will happen in the case of copper? So, copper should get oxidized as copper 2 plus or maybe copper 2 plus and this plus iron should get reduced as hydrogen gas if copper is. So, you start with the 2 equilibrium 2 equilibrium in this case. What are the equilibrium? Let us take the case of iron for example, what are the 2 equilibrium involved here that leads to corrosion? You have to start with 2 equilibrium right. What are the equilibrium that are involved here right? Before corrosion there are 2 equilibrium coming to picture. One is iron is in equilibrium with the Fe 2 plus ions ok. Again to make it simple I want to make this one more variation here. You immerse iron in Fe 2 plus and the concentration is equal to 1 molar right. Similarly, in this case I have a copper and copper 2 plus equal to 1 molar I assume this make assumption right to make it more simpler for you ok. So, how do I start with? How do I start? So, first of all you calculate E cell right. So, before calculate to get E cell what do you need? Yeah you need the equilibrium potential for 2 independent equilibria right isn't it? So, you need to calculate E cell to calculate E cell you need what? You need the equilibrium potential for 2. What are the equilibria here in can you write? What are the equilibria involved in the case of iron? Can you please write here in your papers what is equilibria involved here?  What are the other one? 2 H plus plus 2 electron gives you hydro is 1 equilibria right. So, equilibrium 1 equilibrium 2 for this right.  So, it is for 1 the 2. Now, these are the equilibria now one should become cathode other should become am I right or not ok. So, let us take the case of iron and try to solve the problem. So, what is the equilibrium potential for Fe 2 plus plus 2 electron Fe with respect to this problem minus point why you take minus 0.44 why did you take that? Yeah why did you take that? You were right I mean why did you take minus 0.44? Reduced also will they have same potential only same will sign will change if I am going to take iron as getting oxidized or reduced is the equilibrium potential sign invariant or sign variant right invariant right. So, minus 0.44, but why not minus point something else why did you choose you are right why did you choose you look at the problem there yeah you are talking about a standard here you see iron is immersed in activity is equal to 1 that is why you are taking minus 0.44 if the concentration is different for example, if I say it is 0.1 molar would you have minus 0.44? So, what happens in that case you have to now calculate that actually right you have to calculate it please understand. So, you need to calculate that in order to get the values. So, I made the life simple by assuming that both equilibria are in the standard state. So, we are using the standard potentials. So, let us assume that both copper is corroding and iron is corroding let us assume that please find out whether corrosion occurs or not. Can you please make a calculation and see assume that assume copper and iron corrode. So, what happens? Can you find a E cell if you assume that that iron is corroding and copper is corroding what happened to E cell? Since E cell of iron is positive therefore, iron is corroded. It will corrode. But E cell for copper is negative therefore, copper is not corroded. It will not corrode right. So, it is possible that you can come to a right conclusion. You may assume whatever you like you may you may even assume that iron is not going to corrode and say that it is E c minus E a then you will get into a negative sign. So, it is possible to to compute and say that the metal corrode or does not corrode. I hope each of you label to make these calculations E cell is equal to E c minus E a. So, what happens? We assumed that iron is corroding. So, what happened minus of minus 0.44 and what is E c? It is 0 E cell is equal to plus 0.44 volt. So, iron corrode ok. In this case you take this this case E cell equal to what? Is equal to you assume that copper is corroding that means E cell in this case is equal to 0 minus of plus how much 0.337. So, E cell is equal to minus 0.337. So, is is is a volt. So, copper cannot corrode. So, understood ok. So, it is possible for us to predict if a metal will undergo corrosion or not. Now, measurement of electrochemical potential is much easier. It is very easy you go to lab and in about 5 minutes you can measure it ok. All you need to have is a voltmeter of high impedance value, you need a reference electrode and the metal that you are interested to measure the metal or other system whose potential required to be measured. So, I suppose you people now are now clear in terms of the first concept of how do we really predict if the metal will undergo corrosion or not. To extend this argument I want to pose a problem to you. The problem is I take tin ok, in in water of pH 7 ok. Two conditions take water and immerse tin here. In another case I take water I have tin I close this here. It is open ok. It is what I mean in this case it is closed no oxygen present no oxygen present ok and the water of pH is about 7. So, the pH of the water here you know the water pH I make the following assumptions. What are the assumptions here? The assumptions are large amount of water pH does not change with corrosion. Two in the closed system in the closed system what you see here the space between water and the lid and the top lid is very small and you have large amount of of tin in the system. You understood the problem ok. I have given you pictorially how they are looking like. One beaker where I put tin I have taken in water of pH 7. Other case I have taken tin in water, but it is closed and this space is very small and it is no oxygen present. I have two questions for you the question is will tin undergo corrosion or not ok. One ok now the questions are question will tin undergo corrosion. The second thing is can tin continue to corrode irrespective of the time that time of exposure. You understood the problem? How do you address this problem? How can you solve this problem? The first question for example, what I can give you is I can give one more information for you. I can other information that I like to give you what information that you need because it is not sufficient. The other additional information is SN is corroding if at all if it corrodes it is going to be as SN 2 plus. The concentration of SN 2 plus always remains 10 power minus 6 moles per litre. The partial pressure of hydrogen can be considered as say 10 power minus now this I am not going to change this ok. This is left out ok ok. Now what do you think will happen? The partial pressure of hydrogen may vary I put this way. I did not part the partial pressure of hydrogen may vary or you start with let us say you can start with or let us say 10 power minus 1 start with 10 power minus 1 atmosphere ok. I put this I will go back to this problem. I have defined this problem in this manner and I have tin here. I have tin exposed to water. One case vessel is open to atmosphere and the other case vessel is closed. The space between the water and the top lid in this case is smaller. The pH of the water remains same all the time at 7 and SN 2 plus in this case is 10 power minus 6 year minus 6 year moles per litre right and and of course, there is no oxygen percent. If that is the case then can you say how these systems are going to behave in terms of corrosion are they going to behave corrosion with a time same manner or it is going to be different if so how they are going to be different or to start with can you think that tin will undergo corrosion or not. So, that prediction you should be able to now do that. I think you are you know having enough understanding of what electrochemical equilibrium is you understand what the corrosion is with the equations that you have the relationship that you understood you should be able to tell how these systems are behaving in the corrosion point of view. Now, I just want to know I just want to give this your assignment for you and I want to see this answer when you come to the next class ok. So, please do solve the problem and you know send it by email and the TA will be able to go through and you all can discuss please everybody discuss, but do not copy your answers ok. Understanding is free you should always discuss generally you will be able to understand the concept ok, but solve the problem yourself independently do not do that ok. So, please do this and tell me how these systems will respond with prospective time ok that way we can do that and based on this I will give you some more problems and I think we can we can work on that ok to make your understanding better. Before I move on to the next topic of how do you calculate the corrosion rate? We talked about to predict corrosion rate. How do you calculate corrosion rate? I want you to understand one concept ok. See they are very elementary you know I am not supposed to discuss in this course, but they are very vital if you need to understand corrosion that is the concept of pH what is pH yeah yeah it is related to the activity of hydrogen ions in a solution. So, it is a concentration of hydrogen ions in solution please I am going to use activity and concentration in a synonymous manner because otherwise our life is going to be complicated you cannot solve any of the problems ok. So, it is related to hydrogen concentration how is it related to yeah it is negative logarithm of of H plus S equal to please understand this please look at. So, when I when I say pH 5 and pH 9 please understand the question when I say pH 5 and pH 9 how many times the hydrogen concentration changes 10 to the power 4. So, it is very important people think you know the corrosion of steel is happening at 4 they will get surprised it does not happen at at at pH 9 it is only 5 it is not 5 it is a 5 orders are difference in the hydrogen concentration corrosion involves reduction of the H plus ions. So, please get that feel of it what you are talking about you also try to get the feel of what is molar and what is equivalent weight please understand these are the terms you should know I am not going to talk about here atomic weight, molecular weight, equivalent weight these are the terms I think you people should for a time period get familiarized with and even the concept like solubility product they are chemical terms, but they are very very useful for us to understand why corrosion occurs in some conditions why corrosion does not occur in some other conditions right. See please look at we are scientists as much as engineers you need to understand why why is not there I think there is no point in studying m tech corrosion course there is no do's and don'ts for you guys it is for you to get analyze tell what happens based on what you see is environment you go to industry not simple you know you find the reaction occurs some reaction vessel corroded you know and you say you know this company we are using another company says it is failing here they rise the temperature only by you know 5 degrees start cracking unless you understand the relation between the parameters that affect corrosion you cannot really give a solution to the problem ok. So, you need to understand interrelation between corrosion and various factors affecting the corrosion processes. So, we will end our discussion related to what is called as the prediction of corrosion. Now, comes can we calculate then we calculate corrosion say I have immersed zinc in let us say hydrochloric acid you know how to compute whether it corrodes or not whether it corrodes or not use in this equation. Now, in zinc in hydrochloric acid what will be rate of corrosion ok. So, what will be the rate of corrosion of zinc? So, question can you make a calculation question what are the governing equations what are the governing principles for that that is our next step. Now, let us look at the corrosion in details right let us look at the corrosion here I am looking at corrosion like this I am illustrating this corrosion process in simpler terms right. Before corrosion occurs zinc is in equilibrium with the zinc ions right see that hydrogen is in equilibrium with the anions both of them establish potentials what do what do they call that potential called equilibrium. Now, does it corrode here does zinc corrode here does not corrode rate of forward reaction equal to rate of backward reaction. Will there be any hydrogen evolution here no hydrogen evolution because hydrogen ions combined with electron form hydrogen gas and hydrogen gas in turn give electrons and form H plus they are equilibrium conditions. So, I define this as H plus use you this H and define this as zinc 2 plus this 2 electron and zinc this here this should happen now right. And if they are in the standard state for our assumption the voltage e for that is equal to 0 0 and the standard state e is equal to minus 0 point and I short this what happens I use an electrical cable to connect these two what will happen the potential of this is 0 0 and potential of this is minus 0.4 now I am just shorting these two so, what do you think will happen when you when you take a copper wire I have a resistance in the in the copper wire I have a resistor ok. The resistance is infinite and this side I I have voltage which is say minus 0.4 and this side the voltage is 0 0 and now I lower the resistance I I make it 0 light. So, what will happen current will the current flow or not the current will start flowing the moment I remove the resistance the current starts flowing am I right or not. So, you have an infinite resistance they are not connect talk to each other. Now, they have independent potentials the independent equilibrium that you have right and I short this with a wire this will start moving towards what happens let us look at this I draw like this this is called a potential axis so, potential axis this is 0 0 this is H plus H and this is minus 0.44 volt volt this is F u 2 plus and F u 2. I remove resistance what will happen this potential starts moving towards this and this will start moving towards this will it happen or not is it not. So, the 0 the potential of the hydrogen electrode will tend towards positive I am sorry the potential of the hydrogen electrode tend towards negative and that of zinc will tend towards positive move towards like this and the current will start flowing am I right. If I put an ammeter here I can measure what is the amount of current that is flowing I can use Faraday's laws and I can determine the rate of corrosion can I can I can I not right. So, if I can use an ammeter here I measure the current and I know the current I can use the Faraday's laws I can determine the corrosion measure it called measurement. Can I calculate it without measuring using ammeter can I determine what will be the amount of current that is flowing between this and this. If there are governing equation then that governing equation will tell us so, what should be the amount of current flowing here and that current can be used to calculate the corrosion rate based on the Faraday's equations. So, what we are going to do in the in the subsequent lecture is to find out the governing equations here between the voltage and the current. So, please notice when the potential is start moving from here to this the current is going to move more the potential is moving more will be the amount of current that is flowing in the system. So, my idea is can I get a relation between the potential that moves up coming down and the current that is flowing on this electrode on this electrode. If I know it I can calculate it I do not have to go and do an experiment in the laboratory it will be right I do not have to do that. So, our task now is to find out the governing equations and then use that equations to compute the corrosion rate of metals. Am I clear? Am I clear to you? Ok that is what we are going to do that. So, then we can answer this question can we calculate the corrosion rate? This of course, is a it is a very involved you know derivations. If you take the Bakris and Reddy book on modern electrochemistry the kinetics are very well derived and nice things are there and there is called as Butler-Walmer equation. I am not going to derive the equation and those who are interested please read that book read other books ok as to how the Butler-Walmer equation is going to be derived. I am going to make a very simplistic approach so that you know you are from somebody from you know metallurgy background somebody from electrical engineering background somebody with mechanical background. So, I do not want you to flood with the equations, but yet I want you to appreciate the governing relationship the governing equation so that you can able to calculate yourself tomorrow ok. So, that is our next task of how do we really compute the corrosion rate of the metals. Am I right? Actually, am I clear to you? So, far what we discussed are you people clear? So, let us go to the next step of how we compute the corrosion. Let me start with the equilibrium condition right. Let me start with the equilibrium condition. What is the equilibrium condition? Let me take a simple electrochemical equilibria. What is that equilibria?  So, very known to you. In the standard state, in the standard state what is the E value for this? Are you clear? This is an equilibrium. What does it mean? The hydrogen releases electrons it forms H plus H plus accept electron and forms hydrogen gas. So, it is in equilibrium condition. So, how do I pictorially put this? I put this pictorial like this. This is the a platinum wire a metal and I have H plus I have hydrogen gas. Now, here now what is happening? Please look at it. If I able to visualize if I have the ability to go and see through my eyes what is happening at the interface right. This is the interface right. What is the interface? This is by platinum metal and this is the acid right. So, what is happening? One reaction is going as H plus. The other one H plus goes like this electrons are there the electrons come over here only ok right and it it becomes what it becomes now the hydrogen molecule. Please look at the rate of forward reaction equal to rate of backward reaction. Can I say this? So, the rate of forward reaction is equal to the rate of backward reaction right. What is the forward reaction? The forward reaction here is is what is H going as H plus plus electrons. What is the backward reaction? H plus coming as as what is the unit for rate of reaction? When you have to guys know what is the unit for rate of reaction? R equal to is given as rate of reaction is equal to what? Is equal to moles per unit time. Now, we are going to do it in a area going to be unit area am I right. What are the moles? We have given you before how many units of hydrogen is getting transformed to X plus. So, mole per unit time per unit area is what is going to be not you simply say area here not unit area it is area right mole time area gives you this. Now, what is happening here? Please look at please you have to be with me now. In this reaction electrons are released in this reaction electrons are accepted. So, what does it mean? It means what is the direction of current in normal electrical engineering? What is the direction of current? The direction of current current flow right direction of current flow is equal to reverse the flow of negative charges. Why when it charges it can be electron it can be any ion it can be anything right. So, it is the direction of flow of current is is is the opposite of the direction of flow of negative charges. Now, please look at this interface we are talking about electro chemical reaction. Now, look at this interface now. Now, current in this case current how does the current flow? The current is flowing from the solution to the metal here the current is sorry. In this case the current is flowing from the metal to the solution in this case the current is flowing from solution to the metal right am I right or not? Is it ok? I am not ok. I am not seeing any response from you people. So, it is it is is it is electro chemical equilibrium. What is electro chemical equilibrium? There is a flow of current associated with the reaction rate. Now, now when hydrogen gas is converted to H plus H plus ion moves from the metal surface to the solution it moves like that. So, it carries a current in this direction. When H plus ions are getting reduced it carries a charge in the opposite direction that means, the current is now flowing like this. So, that means, the equivalent of that is going to be I ok like this here I is going to be direct. Can I write like this ok? In the first case I is in this direction in this case in this case I is in the this direction. Current moves differently because the charges are different in this case. Am I right or not understood? Now, let us put all of them together. What do you understand? You understand that at the interface there is no net oxidation, there is no net reduction, but the current is flowing back and forth. It goes forward, it goes backward, net amount of flow is 0. So, net amount of reaction is 0. So, no corrosion, no reduction, no oxidation taking place. System is under equilibrium condition. Am I right or not? So, system is now defined as under equilibrium condition. How do I calculate I? Can I calculate I here? Is it possible to calculate I? I can calculate I if I know the rate of reaction. How do I do that? I is equal what is equal for I? I equal to what? Moles ok, pair time, pair area, multiply by what? A number of electrons into paradigm. Am I right? I equal to the moles per unit area, the number of electrons am I right or not? This is I right. So, R is equal to I upon n. Have I made clear to you or not? Too much too much of electrical engineering, too much of electrochemistry I suppose this would be easier right. Now, I have converted this rate of reaction into current ok using this equation now. So, I upon n number of electrons per Faraday is your this all you might have studied in 10th or you know 11th and 12th and all I suppose ok. So, what I am trying to say now the rate of reaction is related to the current here ok current here. Please notice in this case what happens? The rate of forward is equal to the rate of backward and so, the I is equal to I naught yeah oh I am sorry yeah ok I I go back now in the case ok. It is good, it is good that you guys are telling that yeah. Now, we have seen now the rate of reaction R is given as I upon n f under equilibrium what happens? The rate of oxidation is equal to rate of reduction ok. Then what happens? Then and what happens now I naught by ok that means, I tends to become I naught. What is I naught? I naught is defined as exchange current density. Suppose you guys are now getting clear pics about what is an electrochemical interface? What is an electrochemical interface? I stop here now. What is an electrochemical interface? The electrochemical interface is where there is oxidation and reduction taking place right am I right or not and so, the current flows back and forth. If the rate of forward reaction equal to rate of backward reaction then the system is under equilibrium conditions. At that condition the amount of current transfer is equal to exchange current density ok. Ok let me just draw here ok. Just take the case of hydrogen gas converted to H plus. Now, what is happening? Now, the electrons are released on the surface right. Now, please look at hydrogen here is moving here as H plus what is the what is the what is the direction of current? This is the direction of current it is going please current is a vector now please look at current is a vector ok. Now, H plus moves here and accepts on electron. What happens? It goes out as a gas. What is the direction of current here? I is moving now this I and this I must be same or same it should be different it should be same if the system has to be under a equilibrium and so and this I is equal to I naught ok if the system is under equilibrium condition and this I naught is related to rate of reaction through this equation right I naught upon N and F look at this ok. So, today I think we should stop here. The exchange condensity is an equilibrium parameter please understand. The exchange condensity is a an equilibrium parameter similar to what? Similar to the equilibrium potentials. Can I say that? The exchange condensity is a parameter similar to equilibrium potentials. The only problem is it is not easy to compute I naught we will we will we will try to talk later, but this is a difficult subject. It is not easy to compute I naught that is the real difficulty that we have, but it is enough for us to say that I naught represents the equilibrium existing of the interface between the solid surface and the electrolyte divided into we are we are discussing ok. So, with this I will stop here we will continue in the in the next class ok and I hope that in a in one or two classes we should able to get an answer how do we compute corrosion rate for a given metal ok. Because you know that corrosion is a non-equilibrium state it is a spontaneous one right. So, first you define what equilibrium state is then you start deviating from the equilibrium then you are going to get into corrosion right. So, first definition is how do I define in equilibrium condition. So, define in equilibrium condition then I think I will know how it deviates and that deviation is going to be now computed ok. So, today I will stop here please do go through these nodes actually and understand what you are discussing. As you see that the complexities of electrochemistry will keep building up ok and it will be very easy provided you understand step by step ok these concepts ok. So, concepts is the key without concepts is very difficult for you to make any any calculations or computations because corrosion is there are so many variety of forms of corrosion ok different environments different metals so many of them ok. You cannot give a table and then tell you know please make a computation you must know the governing equation and then try to use the equation so that the corrosion rate can be calculated for any system that you are interested actually right. So, that is a purpose of the this this particular lecture ok. So, please go through that and you please solve the problem which I given you so that that gives you a clear understanding of how we predict a metal will undergo corrosion or not ok. So, today we will stop it.


Okay, welcome back everybody to our second lecture on PC310 Church Administration Management. We have been talking about volunteer management and we're continuing that. Tiffany, you have a question? So when we studied about the staffs, when something goes wrong, you were telling about the three strike policies. That's how you do it. So what's the case of volunteers if you notice something is happening with the volunteers. How do you actually be corrected and we can't say everyone will actually take the corrections and change it. So how the conflicts in a volunteer sector actually happens and how do we solve it? Good question. Good question again. So church staff, we have like we said, like you mentioned, we have this three strike rule three times and we have to see what action to take and so on. Volunteers, we have to, so at least the way we work at APC is even with volunteers, we are strict. So the thing is this, volunteers, we did not want volunteers to have the mindset that, hey, I'm coming and doing something for free. So you cannot tell me anything. We did not want them to have bad attitude, you know, because then that is a very unhealthy attitude.  That means there has to be commitment and you have to work in a certain way. That means you have to work with excellence. If there is preparation and to do your preparation and calm, we are striving for excellence in everything.  And if you're not able to meet this, then we will have to release you and you try and do something else that does not require same level of commitment. Example, example, you know, for those who want to volunteer in the worship team, the level of, our requirement is very high. That means, example, I'm just saying, before, so the song, the worship leader for that particular Sunday will send out the set list saying, look, we are going to come prepared with these five songs. We are going to do these five songs on Sunday. So the people who are rostered for that Sunday, they must learn the five songs, they must practice their part in the five songs, depending on which instrument they are playing. They should come ready, already prepared for the practice. So before the practice, they have done their preparation, so which may, for example, depending on their skill level, it may take about one hour. Or if, you know, sometimes they may take even two hours, depending on how much skill they are. That means they have practiced for one or two hours before coming to the team practice. So the team practice may happen on a Saturday, for example, or it may happen Sunday morning, one hour or one half hours before the service, whenever they schedule. But for most locations, the team practice will happen on Saturday. So before these people come to the team practice, they have already spent about one or two hours practicing their part for those five songs. Then they come to the team practice. Team practice, the team is practicing all the five songs together. And that will be for one and a half, one or two hours depending on when they practice. So that commitment is there. If you cannot, if you don't come for team practice, you cannot play on Sunday. You can't just show up on Sunday and say, you know, you have to be there for the team practice. Then on Sunday, you have to come early before the service, sound check has to happen, you know, everywhere. So that, so you can't even just show if the service is starting at 8 o'clock in the morning. You can't show up at 8. You have to show up at 7.30, because the sound check has to happen, all those things have to happen. So the commitment is a little higher. That means to sing on Sunday morning, you have actually spent about, you know, roughly about three hours, three to four hours of practice before you can, you know, lead, be a part of the worship team on Sunday. That's going to lead for about 40 minutes. So four hours of, I'm just roughly giving an estimate. Four hours of practice has gone in for that person to be part of the worship team for 40 minutes, but that's the commitment that's required. Now, if they don't do this, and we've had to, and we just say, sorry, you cannot. You know, if the person comes without practicing, they'll just say, hey, sorry, you cannot be part of this team. So at least at APC, what we have done here is we've created a culture where even if you're a volunteer, they're expecting you to do it well. They're expecting you to do it with excellence. If you can't do it, don't want it. Nobody's forcing you to do it. If you can't do it well, don't want it. So the consequence of not doing and not coming on time, not being committed, not doing something with passion and excellence as a volunteer is he will release you from the opportunity to volunteer. Thank you very much. And again, we apply the same thing, that is, you know, first we give a warning, you talk to the, you're supposed to come at 8 o'clock, you came at 8.30, see what happened. Then, or you came without practicing, or you were not doing it properly, you know, one or two warnings. And if they still continue like that, it's okay, please sit down. Whenever you're ready, you can, or you serve in some area where the requirement is not that stringent. Time commitment is not so. We have to be strict with volunteers also. And I remember, actually, this is a very bad thing that happened. I tried to remember which year it was. So, again, I'll go back to our worship team. One of the requirements that we had put down for our worship team and all this is in writing also. If you are part, so you have, first of all, you have to be committed to the local church before you can volunteer in the, any team that will be committed. So, first, that's the first requirement, you have to be committed to the local church, then you can volunteer in the church. And if you're volunteering, you also need to be faithful to attend the services. And especially for the worship team, there was a time when we had people in the worship team, they used to come to church only on the Sundays, they were rostered to lead worship. On the Sundays, they'd be missing. They won't even come to church. So, we observed this, then I spoke with our worship master, I said, hey, this is very obvious. These people, I'm not saying the whole worship team, certain people, they would come to church only on the Sunday, so when they were going to lead worship. Other Sundays, they're missing, they're not even coming to church. Then I said, please talk to them. I remember, so he spoke to them, nothing changed. Then I got involved, I stepped in, I spoke to them. I said, see, be a quiet commitment to the congregation. Before you can be up on stage and lead worship, you must be committed to this party. That means you've got to be here listening. Plus, the other thing we notice is sometimes they will lead worship. After worship is over, they'll be outside the church. They won't be sitting inside listening to the message. So, we made a requirement, after you lead worship, you must be seated on the front row. You can't be just loitering around outside. No, no, this is not, you're not coming to just do a show. This is part of worship, and you need to be receiving the word of God. You need to be up in front. So, we made these things. And this was a season now. Things are very different today, but we went through this. I think this was back in 2010, 2011 or 2012. I forget which years this was. We went through this. So, we were speaking to the worship team, especially a few people, not all, but few people were, you know, kind of, they're not taking their commitment to the church seriously. So, finally, I called those people separately to the church office one Saturday. I remember that meeting we had. Just those people. I didn't call the whole worship team. I called those people, and then I spoke to them along. There was a worship pastor, others were there. I said, see, this will not continue. And these were experts. I mean, like, they were very good musicians. Like, one person who was sitting there was, you know, was like India famous. You know, like, he was a lead guitarist. He was so renowned all over in India. Like, that level of musicians, they were beautiful. They were all sitting there. I said, see, this in church, if you're going to come and lead worship, you need to become, and this is not the first time I'm talking to them. We've talked to them many, many times, but this was like the last meeting. This is serious. I called these few people in along with worship pastor and a couple others. This is the issue. You know, you have to be in church. If you cannot be in church, please step down from worship team. We don't want to. You know, we're not asking people to come and do a show for us. That's not what we want. And, you know, so we went through the whole thing. After that meeting, that whole crew left. They left the church. Now, these were among our best, you know, worship musicians. I mean, not the whole thing, but there were a handful of them. The whole group, they left the church. Now, one, I felt very sad because that was not the reaction or the response I wanted from them.   That is your commitment must be first to the local church. You should be here every Sunday receiving the word of God. Then you can be upon stage to lead worship talent wise. They're very great. They're famous. They didn't be invited all over the country, etc. People and they were known. But this is what we require. That was it. That was like the last meeting I had. They left. They stopped coming. Then I said, it's okay. I mean, I've done my part and, you know, so to answer your question, you know, and the thing is, is that we have to be strict. And sometimes this happens when we correct even volunteers. They may leave the church, but that is not the intent. We're not sending them out of the church. We are saying you're a volunteer, but we have certain commitments. You have certain standards. And we will live by that. We will abide by that. And even in the pastoral side, you know, like the example we had, we have a policy here that if you're a pastor, you should not engage in any financial dealing with anybody in the congregation. You know, so that's something I should keep telling our pastor team.  You want to do business or whatever you want. You do it outside, but don't enter into any kind of financial dealing with any person in the congregation.  Within the congregation people, I will not, you know, we will work for people outside, but not because the problem is, as a, you know, if you engage with people in the congregation, something goes wrong, it will affect the relationship in the church. Problem is happening with the business, you know, some business dealing, something else, but something goes wrong there, it will affect you. So let's just keep away from this. Then the VIP did have an actual couple. They got involved financially with some people in the church. It was a big mess, big mess. And I had to, you know, had to make a change, but then when I made the change, they left the church. The Bastille couple was part of our Bastille team, but I had to do it because this was our clear guideline, you know, part of the Bastille team, you must not engage financially with people at the congregation because of this reason, you know, and it actually happened. They got in financial role, it became such a big mess. It was such a problem. And I had to sit and, you know, try to sort it out and all those things, but so we have to be careful, you know, and they said, for whether they're volunteers or we have to have guidelines and follow those kind of things. Okay, yeah. The Bastille leaders, you know, we've seen them for four or five years. That's not all of them. So if we have pastors and leaders who, you know, without informing us, they go and visit people's homes. So here we don't mind. Like we don't, actually, I don't even know who goes to visit's home. You know, I don't know. And we don't mind. Like, you know, our own pastors, our Bastille team, and we have a member care team, they will go and visit and meet people. And I don't care.  I'm not thinking about it. I'm not involved. And I don't ask. And we don't have a policy such that they have to inform me everything. They don't inform me about everything. They're free to go and visit whoever, whatever happens. Even among people in the congregation, our life group leaders, member care pastors, they all go and visit and they have good time. And we're very happy about that. Only thing, if there is any kind of anything goes wrong and news comes, then I will ask, you know, like if somebody goes and keeps asking money from other people or, you know, something goes wrong, usually the news will come. So then I would definitely ask. Otherwise, I don't even know what's happening in terms of who's visiting. Yeah. So there's complete freedom that way, but as long as everything is done properly, it's fine. Only when something goes wrong, then we have to step in. Yeah. All right. So let's move forward in our understanding here about volunteer management, just get into some of the practical things that we do here on page 31. So when we are getting new volunteers on board to join the teams, of course, there's an orientation process. We welcome new volunteers. You know, we introduce them to their teams and usually various volunteer teams have their own WhatsApp groups now. A lot of this coordination happens on WhatsApp right now. So they're introduced to their teams. They add it to those WhatsApp groups. Then we try to help volunteers to understand the values practices, standards, and goals. How we work, right? That we want to, you know, we are committed. We are pursuing excellence. We want to work with unity. So the culture, how we work, you know, we try to get that across. Have them understand. Most of them, if they've already been part of the church, they can observe this. They can see this. So, you know, a lot of it is already there. They can see it. Now, we as an organization, we want to be good in what we're doing.  So especially most of the people who are coming, they are professionals. They expect us also to be professionals since we should work properly. Otherwise, they will be, the volunteers will be turned away if they see that we are not very bad in our work. We don't do our work as staff. We don't do our work properly. So we also have, we maintain those standards. We clarify our team policies and guidelines, what you should do, what you should not do, what is expected of them. We go through it. And then also training is provided. So, you know, for different teams, training is required. And so we have these trainings scheduled for them. Sometimes it's just a matter of come and watch us for the next three weeks, how things are happening. Sometimes it is more specialized training so that they can do well. We maintain the quality. Teams are motivated. And we want to keep excellence, right? Take 32, we need to be clear about the skills or abilities volunteers need for different teams. So if the volunteers have those skills, they can of course serve on the team. If they don't have the skills and we don't put them in that team, put them somewhere else where they can actually be useful. So we can't put every volunteer in just every team. They have to have the required skills and so on. And in some cases, the knowledge and skills can be imparted through training. So we give them the training they need or they can learn it like on the job by actually doing the work. So we give them opportunities for learning practically how to do things. So these are things we think about. Provide them training. And just this is some side note here. Training can happen through lecture training, hands-on training, there are group discussions or somebody coaches or mentors them in what they have to do. So different ways the training can happen. Team leaders also need some guidance on how to provide the training for their teams, how to care for their teams. So we also invest in the volunteer team leaders so that the team leaders can take good care of their team. So that's also something you look at. Is this team leader taking care of doing a good job and taking care of the team? Sometimes if the team leader is failing, we need to help the team leader and help him or her do better. Just as a side note, people learn through different ways visually or listening or by practically doing things. So we need to accommodate all of that in our training. So people like to see pictures, they like to listen, they like to talk, they like to physically do things, they like to interact, they like to think through and some people may just want to work along. So we just have to accommodate various people who like to learn in different ways. And how do we keep volunteers motivated? So that's very important. So we need to help them see that they're actually doing God's work. This is not, you're not doing this for APC, you're not doing this just for some organization or you're doing this for the Lord, you're doing it for his kingdom and for his ministry. So that's very important. Also, we have them see that this is part of our vision, the church's vision. So if they're connected to the vision of the church, they will be passionate about what they are doing. They're contributing towards the vision of the organization. Plus, they themselves are growing. So they are learning something. They are learning some new skills. They are developing their own potential. That also motivates them. It can give them opportunity to serve as leaders and decision makers. Again, they're developing those kinds of skills, leadership skills, decision making skills. And also, generally what we do is, if somebody is volunteering, we always give them the preference whenever we want to hire somebody. If somebody has been a volunteer, we prefer hiring them for full-time positions for the church as opposed to somebody from outside. So that also motivates them. Hey, if I volunteer, and in the future, if I want to work for a church, this is the path that I need to go. I need to be a volunteer and they'll help me be a full-time staff for the church. So these are some things that really motivate them to engage meaningfully. Okay. One important thing is we also are very careful so that volunteers are not overworked or burnt out. So we have to constantly watch, especially if somebody is serving every Sunday, then there's a high chance they can feel hired. I come to church and they make me work. So we have to be careful about that. We don't want to overwork them. So that's what we try to roster them. Like, okay, one Sunday a month or two Sundays a month, you do something. We try to roster them unless they themselves are willing to serve on more Sundays. Right. Now, a few other things. Volunteer management can be done through software. We are not using that yet, but in our church management software, there's the place to have volunteer teams and volunteer teams can work. But our plan is eventually to have that available and manage our volunteer teams through an online church app, through our church app, actually. So volunteer teams and staff relations. So I mentioned this in the very beginning. So this is very critical, how volunteers and staff are working together. So staff should be trained. We try to tell people, staff to be respectful to understand the volunteers. And like I said in the very beginning, we should treat each other with respect, trust, and celebrate each other.  You're doing something good. So we trust, respect, and celebrate each other. We should work together as a team.  Work as a team, so on. And we need to communicate. So if volunteers feel that they're being left out of the communication, they'll feel like, hey, they're not treating us separately. So that's one reason why we have these common WhatsApp groups where we can communicate freely with volunteers. So whatever information they need to know, we let them know. And so they feel part of what's happening. If there is a breakdown, we need to detect it and address the breakdown relationship. So what are some of the symptoms that things are not going right? One is, if there's uncertainty about who's supposed to do what, this happens very often. The one is, I thought the church staff will do it. The church staff will say, I thought those people are going to do it. They're point fingers at each other. Saying, no, they were supposed to do it, though they were supposed to do it. This is what happens. So it's very important to very clearly say, hey, this will be done by these people. This will be done by them. Make it very clear. There's no confusion. Then sometimes if they're not being cooperated, they're going and working off on their own instead of working together. Then it's a sign that, hey, something has gone wrong. Or if they're not open to each other's ideas and suggestions, staff don't want to listen to ideas from volunteers. Volunteers don't want to listen to ideas from staff. Then that's a sign that things are not going right. Or if they're not sharing information with each other. If you're not communicating directly, they're going around each other. Or if they're using language like us and then it's us. It is them. They are doing like this. We are doing. Then it shows that something is wrong.  This is my dear. Don't come near. You can do with your work. So these are all indicators that things are not going right. So we need to then address these things, basically sit down, talk to them, explain that, you know, we need to work together as a team. We need to be together and so on. So some questions, you know, that we can ask and keep looking at, you know, our volunteer team leaders doing what they're supposed to do. Are they following the guidelines? Are they, you know, being good testimony? Are they serving passionately? Are they feeling burnt out? Do they feel any tension between staff and volunteers? Are they feeling part of the community? Are they just feeling like they're, you know, making them work without appreciating them? So last few thoughts here. We do review the work of volunteers and if you're watching and yes, you know, we maintain the same standards for staff and volunteers. We expect you to behave the same thing. And if anything goes wrong, we tell you that things are not right. What we do is we try to appreciate our volunteers throughout the year. You know, one is every Sunday we say thank you to them. Also, once a year, we have a special volunteer appreciation day. That's close to our church anniversary day where we host all our volunteers for a good meal. And we give them a gift. So every year we think of some gift to give them. I mean, this is just a way of saying thank you to them. It's not like we can pay them for their work, but just to say thank you. So we have a good meal and we give them a gift. Just to say to all the volunteers, thank you. Some other thoughts, you know, people can even volunteer from different places because of online facilities that are available. People can volunteer across cultures. And when we are having people volunteer across cultures, we need to sensitize them to the local culture and customs. So that, you know, nothing of that is hurt in any way. So that's about what I wanted to cover on volunteers. Let's see if there are any questions, points for discussion here. Any thoughts, any questions from anybody? Volunteers, engaging volunteers in church. So when it comes to hiring people, like, you know, when you want to bring people for full-time. When a volunteer comes, when somebody who's been serving as a volunteer comes and says, I want to join the church full-time. For me, I feel very happy about that. Because we have seen that person. We know that person very well because, you know, if they've volunteered for two, three years, we can really see, you know, their passion, their commitment. We know the person very well. So it makes it very easy for us to hire them or to say, yeah, come join us full-time. And also for them, they have understood our culture. They understood what the church is about. So it's not a hasty decision. You know, it's not like they've thought about it. And so when a volunteer comes and says, I want to join the church full-time, it's always a very welcome decision. As long as we have the opportunity, we usually bring them on board. We take them, give them response. But it's much easier than when you're hiring from somebody from outside and you don't know them. You don't know how well they work or if they commit and so on. So that's also a big benefit of having volunteers. Because you already see them, then it's easy to take them on as staff. And almost all our church, not all, but many of our church staff have become staff like they used to serve. Then they joined us full-time. Okay. All right, let's wrap here today. I hope these thoughts on volunteer management have been useful. You can go to the notes and then try and apply them in your church, in your ministry. And let's close in prayer. May I request somebody online to please close in prayer? Let's pray. God, we want to thank you for this morning. Thank you for the lessons that we learned this morning, God. We pray to God that we would be able to apply this in our local congregation and also to help people who are in need of Jesus together, help us to serve you in more diligent ways to God in the days to come. We pray to God that let your kingdom be established and through each one of us God. We thank you for this time. In Jesus name we pray. Thank you. Okay. Thank you everyone. Have a good rest of the day. I'll see you again next week. God bless. Bye now.


The idea of the whole child pays respect to the fact that there are many aspects of human potential that grades can't measure. Besides curiosity and intelligence, children may want to develop creativity, passion, resilience, intuition, confidence, generosity, mindfulness, humor, and many many other important traits. Edith Ackerman's theory of the whole child development identifies four natural urges that drive our growth throughout childhood into adult life. Being me, us, the world, and human creations. Each of these four urges can be divided into two subcategories. To understand them better, let's look at the theory from the perspective of a young girl. Being me is about learning to use my body and exploring my mind. The ability to control my body allows me to discover the world and as a result, I can get to know where I'm at and who I am. By using my body, I put my five senses to work. This is how I learn to walk, speak, listen, and develop healthy habits. Soon, I might impress older folks with my clear speech, good posture, and other physical capabilities. Knowing myself helps me to develop a voice in my home and find my place in this world. It allows me to learn what I like, what I don't like, and what potential is still inside of me. By knowing who I am, I can understand my own subjectivity and form an identity I am proud of. Us is about how I relate to friends, family, and strangers, and my understanding of their thoughts, feelings, and behaviors. Let me begin with relating to others. As a child, I seek the love, attention, and respect from my parents. But I also have a fundamental natural urge to have social interactions with others. That means I need to learn to share and care so I can belong. One day, I want to become a respected member of a group while keeping my own identity. Understanding others is another thing. I want to learn about my friends and their emotions, intentions, ways of thinking, and behaviors interest me. I want to learn to move away from my own limited point of view and integrate other people's perspective to develop a more complex understanding of morality and social problems. Making sense of the world means figuring out how things work. That's why we play. Through exploration, I quench my thirst for seeking logic and discover this universe. Adults call it exploring and investigating. We call it play. That's how we learn. Sometimes it gets messy, but by playing, I realize that some things change while others don't. In other words, I learn how things work. Later, I can become a real scientist who plays with big ideas and theories and explains the workings of this world to you. I am seeking logic all the time. As children don't just want to discover how things work, we also look for consistency where there is little. To make sense of this world, we filter, interpret, and reconstruct what we experience into mental models. I think adults call them schema. This urge for order helps me to reorganize what I learn, infer rules, and apply fundamental laws in real life. Human creations is about me being able to imagine alternatives in my head. If I can image something new, I am able to go and actually create it. Imaginating is one of humans' greatest achievements. Without imagination, all innovation would happen by chance. That's why I need fantasy and a lot of free time to play pretend. This way, I will learn to think out of the box. Through creations, I can express my thoughts and bring my imagination to life, and there are hundreds of ways to do so. I can create atmosphere with my voice, ideas with my head, and pictures that I paint with my hand. If I am given the space, I can create cozy rooms beneath the kitchen table, or one day when I am older, design an entire house. Edith Ackerman was born in Switzerland in 1946. After graduating, she became a protégé of Jean Piaget. At MIT Media Lab where she spent most of her career, she was exploring the interactions between play, learning, and design. Whole child development, also known as holistic education, seeks to engage children in the whole of their being and potential. It assumes that each child arrives at this world with their own set of talents and interests that are to some degree completely independent from the child's upbringing. Some refer to this whole as the mind, body, and soul. The Swiss educator Pestalozzi referred to it as the hand, the heart, and the head. And further still, many others try to sum up a child in four, eight skills, social, emotional, and so forth. But does any such division actually pay respect to the whole? Does it capture a sense of humor, an appreciation of the arts, or the ability to be mindful? For this reason, the work of Ackerman offers a more wholesome perspective. What are your thoughts? Please share them in the comments below. Sprouts videos are published under the Creative Commons license. That means our videos are free and anyone can download, edit, and play them for personal use. And public schools, governments, and nonprofit organizations can also use them for training, online courses, or designing new curriculums. To help us stay independent and support our work, you can join our patrons and contribute. Just visit patreon.com slash sprouts. Even one dollar can make a difference.