When I was little, my sister and I shared a room and she had the coolest lava lamp. I would fall asleep every night watching it bubble to the top and float to the bottom. So when I saw this experiment that replicates that lava effect, we had to try it out right away.
All you need is:
- A glass of water (size is up to you. We used a tall, straight vase.)
- A little vegetable oil
- Food coloring
- Salt
We turned our water a lovely pink shade. Some do this after adding the oil but I think it's a little easier to do it first.
Pour in the oil to make about an inch layer on the top. Of course water is more dense than oil so they will stay separate. If you put the food coloring in now, it will eventually sink to the bottom as well and mix with the water but it takes a little longer.
Pour in your salt. As the salt goes through the oil, it pulls some of it to the bottom but then the oil releases and floats back to the top again. Look at the differences when your kids pour just a little salt and when they dump in a bunch at a time. You can keep going as long as you still have salt left and you don't overflow your container! Enjoy!