Science Friday: Sink or Float


Happy Science Friday, friends! I cannot believe that another week has come and gone. I cannot believe that a certain special boy will be graduating from kindergarten today! I cannot believe how much fun we had putting this experiment together!

I hope you are having a WONDERFUL Friday no matter where you are on this blessed globe. Above all, have a fabulous Science Friday!

XX, Megan

Sink or float?

That was the question. We really shot from the hip on this one. We set out to find out if household items (read TOYS mostly 🙂 would float or sink when placed in water. Additionally, we decided that each of us would pre-guess the results for each item. You know, mini-hypothesis’.

I thought about throwing in a discussion of mass and density in here, but maybe we’ll circle back around to the real science behind this experiment in the future. If anything, Science Friday has give ME the opportunity to brush up on my scientific principles.

Buoyancy: This means whether or not an object will float or sink depends on its own density and the density of the liquid it is placed in. In the case of water, an object with a density less than 1 g/cm3 will float. — science

Those two smiling faces above are much more than garbage seekers. I gave the boys each a plastic bag, and asked them to go to their room and choose 5 things they thought would sink and five things they thought would float when placed in water. This didn’t take long and they returned with their loot. I did have to let them know that 10 legos each wouldn’t work as experiment fodder. So back to their rooms they went.

Each of them opened their bags and counted their items out onto the table. We then combined the boys’ items (with a couple of additions from mom), and went to work.

After choosing the items we would sink/float, we made a list of all of our items. We had 12 items total: balloon (with air inside), balloon (without air inside), toy car, plastic washer, lure worm, lego, screw, gum wrapper, toy fire truck, nerf bullet, father, and putty.

At the top of our list we wrote each persons name so that their guess as to whether each item would sink or float would be recorded. We left another space, A for Actual, to record the outcome of each item– sink or float?

I filled a mixing bowl with water, and we were off. Step-by-step with picture below!

1. Gather

Gather a bunch of items in preparation for determining which will float and which will sink.



2. Count

Count your items and decide how many you want to “test”.



3. Choose

In our case, we chose 12. But I do wish I had remembered to add oil to the list. Next time.


4. List

Make a list of your items, with the names of all participants across the top as well as a space for the actual outcome of each test.




5. Guess then Test

Have each person make a guess about every item before you put it into the water. Then record the actual. Did the item float or sink?


6. Results

Check out your results! My boys were all about seeing if they correctly hypothesized the fate of each object.


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