- Flask or empty water bottle (a clear plastic bottle works well)
- Vegetable oil, cooking oil, or baby oil
- Fill the flask most of the way with your choice of oil.
- Fill the rest of the flask with water. The oil floats and the water sinks to the bottom of the jar under the oil and looks like little, clear blobs.
- Add a few drops of food coloring; your choice of color. The food coloring is water-based, so it will also sink and color the water that is now at the bottom of the flask.
- Break an Alka-seltzer tablet into a few small pieces, and drop them in the flask one at a time.
- Watch your lava lamp erupt into activity! As the chemical reaction slows down, simply add more Alka-seltzer.
A lava lamp works because of two different scientific principles: density, and polarity.
Concept 1: Density
Density is the measurement of how compact a substance is - how much of it fits in a certain amount of space.
(The scientific equation is density = mass/volume.)
If you measure an equal volume of oil and water, you'll find that the water is heavier than the same amount of oil. This is because water molecules are packed more tightly; a cup of water actually has more mass than a cup of oil.
Because water is more dense than oil, it will sink to the bottom when the two are put in the same container. Density is affected by temperature—the hotter a liquid is, the less dense it will be.
- Boiling (or Florence) Flask; or any clear glassware
- Baby oil
- Mix about 1tsp of white paint with about 100 ml of water
- Add a generous amount of glitter to the mixture
- Pour the white, glittered water into the boiling flask (or any clear glassware). This should fill your glassware about 1/5th full
- Fill the rest of the glassware with baby oil. The clear baby oil is less dense than the water mixture and will stay on top
- Break an alka-seltzer tablet into a few small pieces
- Drop the alka-selzer pieces in the flask one at a time.
- Watch as the snowstorm appears!
- As the reaction slows down, simply add more alka-seltzer.
Just like in the lava lamp project our homemade snowstorm was created when we used alka-seltzer to react with the water to produce carbon dioxide gas bubbles. These stick to the water droplets. The water / gas combo is less dense than the oil, so they rise to the top of the flask. At the top, the gas bubbles pop and escape into the air, allowing the dense water to sink back to the bottom again. Refer to the science lesson from the lava lamp project above or print this free lesson.