Lava Lamp Science Project
My students and I just did a really neat "lava lamp" experiment! It taught them about many different aspects of science and was a big hit with the kids. Plus, it only required a few simple, easy to find, supplies. If you want to do this project with your child or classroom, you might even have everything you need already.
Alka Seltzer Tablets
A Jar or Glass
Doing the Experiment
First, we poured water into each jar until it was about 1/4 full. The students chose their colors and added a few drops of food coloring into the water, then swirled it around until it was more evenly distributed through the water. Then it was time to add the oil, pouring it until each jar was about 3/4 full.
Lastly, we broke the Alka Seltzer tablets into 4-6 pieces and dropped the pieces into the oil and water mixture. The students really enjoyed experimenting with how the effect changed depending on how many pieces they dropped in. Watch out if you drop in a whole tablet, though! It fizzes up and if you're doing this in a small jar or glass it might even fizz over the edge!
Although the effect might look similar, this experiment uses different processes than an actual lava lamp to achieve its lava-like bubbles. (The day before this experiment we learned all about how real lava lamp works so we could examine the differences.) The students made observations about what they saw and heard as they worked and made hypotheses about what was actually happening.
How it Works
Oil and water don't mix, so the layer of oil simply floats on top of the water. Since the food coloring is water soluble, it dyes the water, but not the oil. The Alka Seltzer reacts with the water, creating bubbles of carbon dioxide. As the carbon dioxide floats to the top of the liquid, it carries blobs of colored water along for the ride. But when the bubbles pop at the top, the blobs of colored water fall back down to the bottom.
Expanding on the Experiment
In addition to the main experiment, we also tested some variations. Most of our jars had room temperature water and we wanted to find out if the temperature of the water would affect the results. We put ice water in one jar and hot water in another. We discovered that the cold water made it hard for the bubbles to get through the oil and they mostly got trapped in the bottom most layer of water. Hot water, on the other hand, resulted in larger bubbles in the oil.
This experiment was an absolute blast! I highly encourage you to give it a try because it is sure to wow your kids!