Have you ever seen a lava lamp before? Your parents might have one left over from when they were teenagers! If you haven’t seen one before, take a look at the photo below!
As you might already know, oil and water do not like each other! Pour a glass of water and then add a drop of vegetable oil. What happens? The oil sits right on top of the water. You may have already known that oil and water don’t mix, but do you know WHY? Check out the video below for a little insight!
Look at the image below. Which object is denser?
The other reason that oil and water don’t mix is that water is polar and oil is non-polar. Because polar molecules only dissolve in polar solvents and non-polar molecules only dissolve in non-polar solvents, neither the water or the oil will dissolve when mixed together. Instead, the water molecules will stick to each other and the oil molecules will do the same.
Now that you know a little background information on your materials, let’s get started!
YOU WILL NEED:
- Empty plastic bottle
- Food coloring
- Flashlight (optional)
Here’s what to do!
- Fill your plastic bottle with vegetable oil until it is about 3/4 full.
- Pour water to your bottle until it is full, but not overflowing.
- Add about 10 drops of food coloring into the bottle. Take a moment to record your observations. What happened when you added the food coloring? Did it mix in with both liquids?
- You should have noticed that the food coloring changed the color of the water but not the oil. Why do you think that is?
- Next, break an Alka-Seltzer tablet into a few pieces and drop one piece into the mouth of the bottle. What happens? Lava greatness!
- If you want the full effect of the lava lamp, set your bottle on top of a flashlight and turn the lights off.
- As soon as the bubbling subsides, just add another piece of Alka-Seltzer to keep the party going!