In Ms. Brady’s class we were learning all about floating and sinking so we decided to investigate how density helps a diver float and sink!
First of all, we needed to experiment with different materials to see what floats and what sinks. We discovered that coins sink and tin foil floats. We tested many materials and had lots of fun!
Then, it was time to make our diver. We were very excited to find out what would happen. We needed a few materials for our experiment;
- Foil divers (Ms. Brady cut these out for us because they are very sharp)
- 2 liter bottles
- Paper clips
- Blue Tac
The first thing we did was put our diver together. For this we cut the straw short enough that there was 1 inch each side of the bend. We then attached the straw to the paper clip and put it on the divers back. We then put some blue tac on the divers feet as the weight.
Next, we filled up our water bottles with water and carefully put our diver inside. We then tighten the lid to make sure the water didn’t spill everywhere! After everything was ready to go, it was time to experiment! What makes the diver sink?
We discovered that squeezing the bottle made the diver sink. When we released the bottle, the diver floated back to the top. But, WHY? Squeezing the bottle causes the diver to sink because the increased pressure forces the water up into the straw. This increases the mass, and density, of the diver causing it to sink!
After all of our experiment we wrote down our experiment and discovery in our science log!