We did this experiment about 4 years ago, and today we revisited it with Kim and Luke.
We got this kit from Steve Spangler, but you can do it with just things around the house.
That's what we did 4 years ago. You can see that post here.
Put cooking oil into a thin container...a 16 ounce soda bottle could work for this. Fill it about 3/4 full of oil. Add water to the container, filling until you are about an inch from the top. (if you fill it to the top, you will have a giant oily mess.
We can see the water is more dense than the oil. The water fall to the bottom of the test tube.
At this point we added Steve Spangler fizzing color tablets
You don't need these. You can just add about ten drops of food coloring to the mixture. (You will need Alka-selter to make the reaction if you use this option.)
Carbon dioxide is released from the fizzing color tablet or the Alka Seltzer. The carbon dioxide caused the colored water to rise to the top of the test tube. When the carbon dioxide reaches the surface, the bubbles pop, causing the colored water to return to the bottom of the test tube.
A beautiful display of science fun.
I got a kick out of this. Kim discovered that she could hear the popping of the carbon dioxide. She shared this discovery with Luke.
Placing the lids on the test tubes the reactions stopped. (The gas could no longer escape the tube)
We now waiting for a bunch of kids to get home from soccer so we can show them our science lesson.
I encourage you to check out this video from our original experiment---4 years ago. It is so cute to listen to the kids as we did this!