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Friday, 26 February 2016

Changing States of Matter

Changing States of Matter

I started the day off with a quick check of background knowledge with a simple experiment I had carried out last year with my students. This invovled ice cubes melting in a glass of water and condensation occurring on the outside. Everyone was able to say what was happening to the ice cubes and some were able to explain why. Two students used the word 'condensation' but no one was able to explain how it occurred. So we proceeded.

Firstly we had a quick discussion about the states of matter: solids, liquids, gases, and I introduced them to two new ones of Plasma and Bose-Einstein Concentrate. It was much easier to understand what the atoms and molecules were doing if they acted it out. 

Getting up close and personal like solid matter 
Moving easily amongst each other like liquid matter

Escaping free like gas matter

Next we experimented with being able to change water into different states. They put ice (solid) into a pot and melted it into water (liquid). The challenge was to change the water into a gas (steam) and then through the process of condensation back into water again. Through this experiment with some timely questions everyone was successful and had a firm understanding of condensation.

Getting water to boil and change states to become steam
What did they notice when the hot steam hit the cold pot lid?
Many items can be classified easily but I wanted to challenge the kids to think about what makes a liquid a liquid? Some are easy to label like water and milk but others more difficult such as golden syprup and tomato sauce. We had to experiment to see if we could determine what was and was not a liquid. Some researching told us that liquids had a freezing point and a boiling point and they could be poured from one container into another.

We froze a variety of liquids such as honey, milk, tomato sauce and oil. We needed to see if they froze and if we could return them to a liquid state and then boil them. Did they give off a gas?

The honey was firm but not hard so that left a question in our minds.

The milk melted easily and was quick to boil

The honey smelt delicious but burnt very fast if not watched.

We discovered that all our frozen 'liquids' had a boiling point and were therefore officially liquids which led to the next student question of 'do all liquids have the same boiling point?' Luckily I knew we had some candy making thermometers in the resource room and everyone was soon boiling milk compared to water. They determined that water boils at 100 C and milk at 75 C so they don't have the same boiling point. Time was up. If only we had some milo!

Friday, 19 February 2016



I thought this one might get their attention.

We began by listing everything we knew or thought about blood and discussed these ideas. This raised a number of questions for research later to find out if they were fact or myth. We watched a video about the Circulatory System which explained some of the basics of the heart, blood, veins and arteries in a fun and entertaining way. 

Our next investigation was into heartbeats. What are they? Everyone was able to find their pulse, although some were easier than others. The questions to investigate just kept coming as we discussed pulses. The students took their resting pulse and then it was time to get moving.

Cardiovascular excercise for 3 minutes on a 30 degree day was a big ask. The kids did so well. After comparing the difference in pulse rates many were amazed. Most of them almost doubled their rate.
After asking their hearts to pump all that blood so quickly around their bodies it was time to work out their approximate blood volume. They did this by entering height and weight information into the online calulator https://www.easycalculation.com/medical/blood-volume.php . Another great question arose from one of the girls asking why she would weigh more if she entered the same height and weight but clicked 'male' instead. We could have spent all day investigating our questions. 

Filling buckets of water and adding red food colouring made their body blood volume so much more visual for them and tipping it out was definitely the most fun.

I think we all left with more questions than the simple one we began with. What is blood?