States of Matter Cotton Ball Experiment

We started off our week exploring the different states of matter... solid, liquid, and gas. During our science lab, I filled Ziploc bags with a solid object (toy car), a liquid (water) and a gas (air). We talked about how a solid object keeps its shape, a liquid takes the shape of its container, and a gas fills the space it is in. We passed the bags around and the students got to feel each of he bags, compare each of the states of matter, and turn and talk about the properties of matter they were exploring and observing.

As we continued our exploration on the different states of matter, I decided to let the students have some fun with this cotton ball experiment.

First, we filled one glass to the tippy-top with water, and filled another glass to the tippy-top with 30 cotton balls. Next, we made a prediction of how many cotton balls we could put in the glass of water before the water would begin to spill over the top of the glass. To show the students how easily the water could be displaced, I filled a smaller cup with water and put my fingers in it while the students watched the water spill over the top. After careful consideration, the class decided that we would only be able to put 8 cotton balls in the glass before the water would spill over.

Then the fun started... as I placed each cotton ball in the glass, the students started counting. It was so awesome to hear the disbelief in their voices as they got closer and closer to using all 30 cotton balls. When we put the 30th cotton ball in the glass, I swear I thought that our principal was going to come down to my classroom to see what all the screaming was about... lol! The students could not believe their eyes! All 30 cotton balls were in the glass of water and it never spilled over!

While we were putting the cotton balls in the glass, I made a quick video of our observations. The students got to observe that as the cotton ball was going in the water, air bubbles were coming up out of the water. The water was taking the place of the air that was in the cotton balls. We were then able to conclude that because the cotton balls were made mostly of air, and the air was being replaced by the water, that is why we were able to put all 30 cotton balls in the glass without having any water spill over.

To add a little visual learning to this experiment, I took a cup and filled it with toy dinosaurs. Then I slowly poured the water left in the cup I used to show the students how water gets displaced into the cup of dinosaur toys. The students watched the water fill all the spaces of air in between the dinosaurs. I heard about a dozen students say, "I get it now, Mrs. Kearson"... it was AHH-SOME!!

No dinosaurs were harmed while conducting this experiment... LOL!