Double double toil and trouble,
Fire burn, and cauldron bubble!
Eye of newt and toe of frog,
Wool of bat and tongue of dog!
Oops! I didn't see you there, I was practicing for Macbeth. Let me put away my witch hat . . .
Ok! So today I'm here to help you make a "witch's cauldron" using the properties of density! I know, I know. It's summer! Who wants to learn about stupid density? Just follow along, I promise you'll get some pretty cool results!
Materials Needed:
- A clear glass
- 1/4 cup of vegetable oil
- salt
- water
- food coloring
Step 1: Fill about 1/2 to 3/4 of your glass full with water. Then add a few drops of food coloring, a little bit goes a long way. I like to use green for that cauldron look!
Step 2: Pour the vegetable oil into the glass. The oil will float on top because it's less dense than water!
Step 3: Now pour some salt on top of the oil and watch your cauldron bubble! You can add more salt at will as the bubbles start to stop.
This is what your cauldron should look like. I tried to take a picture of mine, but sadly my camera phone has not the skill to do so.
What's happening?
Salt is more dense than water. When you pour in the salt, it sinks to the bottom and takes a bubble of oil down with it. Then at the bottom, the salt dissolves into the water, and the oil floats back up because the salt isn't weighing it down anymore.
There you have it! You've made your witch's cauldron. Now, what do you think will happen if you change the temperature of the water? What if you use sand instead of salt? And sugar? Make your predictions and see what happens!
Hope you have fun!
-Xoxkitkat
Author's Note: Sources: http://www.sciencebob.com/experiments/lavacup.php
http://pbskids.org/zoom/activities/sci/cauldronbubbles.html
