After the successful crushing of the can in experiment 3.1, the kids were ready for another exciting lab. Experiment 3.2 is Seeing the Effect of Changing Temperature. Required materials are: ice, water, plastic bottle, balloon, bowl, and goggles.
Things I brought, due to the fact I do not have access to a stove or sink: electric teapot, two large bowls, and a cooler of ice.
Here is a photo of one of my students holding the bottle down into the cold water. The main thing here is to get the bottle very cold and not allow any water in the bottle. You want to sllloooowwww down the molecules.
She had to hold that bottle in there for five minutes, while everyone else got to listen to my dribble (so they thought) about atoms. I got a lot of blank faces when I drew an atom on the board. LOL
Once the bottle was cold, the young man below put the balloon over the opening and made sure it had a good seal.
There are a couple of things to note about this photo. Remember this was done right after the excitement of crushing the can. Notice, the girl has not moved, expect to turn the bottle upright. The young man is a little too far from the bottle. Wonder what they are thinking. Will it explode?
Once the balloon is on the bottle, it is placed in a bowl of hot water. I used the electric teapot to make the hot water.
The balloon inflates, but as you can see the young man thought it was going to explode. LOL This is all it did, which means the experiment worked very well for us this time.
Out of seven students only one (the young woman in the first photo) was able to explain why the balloon inflated. The molecules were slowed down in the cold water, then heated up quickly in the hot water. The air expanded in the bottle inflating the balloon. The molecules moved faster and faster, bouncing off the balloon, making the sides of the balloon push out (inflating it). She won a candy bar. :)
For more posts on what we are doing, click on Physical Science button at the top of the Applie blog. :)