On Tuesday, we completed an activity to learn more about what density means. We learned that density is how closely packed molecules are together in an object (how much space they take up). In the future, we will learn how to calculate density. The students built a lava lamp by combining 2 different liquids of different densities- one sank to the bottom of the bottle while the second one floated on top. When we added alka seltzer tablets to the bottle, a gas was produced which clung to the water droplets and pulled them to the top of the bottle. One the gas bubble popped, the water droplet sank back through the oil because it was more dense. If you would like to repeat this activity at home, it is simple:
1. Fill a clear bottle up 1/3 of the way with water.
2. Fill the rest of the bottle with vegetable oil (leave some air space at the top).
3. Add 3-5 drop of food coloring to the bottle.
4. Add 1/4 of a tablet of alka-seltzer (never use more than 1/4 of a tablet-too much pressure may form if you do).
5. Screw the lid back on.
6. Place the bottle on top of a flashlight to see the magic happen.
