Lava Lamp Density

You can make your own lava lamp to watch as carbon dioxide gas is released, creating a cool and colorful science show.  We’ll talk about density as we go along with the experiment. You’ll need: water a clear bottle or jar (we used a pretty wide jar, but narrow ones work even better as the bubbles are more visible against the outside walls) vegetable oil food coloring Alka-seltzer tablets And here’s what you do: Start by filling the bottle or jar about 1/4 full of water.  Add 12-15 drops of food coloring to it. Then fill the rest of of it up with vegetable oil.  Give the oil and water a few minutes to separate.  You’ll be able to see the two distinct layers, and because the water is more dense than the oil it sinks to the bottom. Drop Alka-Seltzer tablets in. If you want, you can cut an … click to read more

Floating Eggs Experiment

Try this cool floating eggs experiment to study density.  First, make a saturated solution of salt and warm water.  We added blue food coloring for fun too.  When the salt is dissolved, put an egg in it.   You’ll see the egg rise to the very top because the egg is less dense than salt water.  (That’s the middle glass in the picture.) Next, add blue food coloring to a glass of plain water and drop the egg in.   You’ll see the egg sink to the bottom!  What happened this time?  Well, the egg is more dense than plain water, so it sinks. Finally, try a cool trick.   Make the egg float in the middle of the water.  Put warm salt water on the bottom (about 2/3 full).  Then slowly and carefully pour in plain water on top. Gently put the egg in and watch it float between … click to read more