It was a rainy day and I was looking for something fun to do with the kiddos. Then I stumbled across a video on YouTube that sparked my interest. It was a video on how to make a homemade lava lamp. It looked pretty easy and only took a few materials. All you need is Canola Oil (or Vegetable oil), a 2 liter empty bottle, a funnel, water, food coloring and Alka-Seltzer tablets. The only thing I didn’t have on hand was the Alka-Seltzer, but I was able to pick it up at Target for around $4.
First thing you do is to add about 1 cup of water to your 2 liter bottle using the funnel. Next add your canola oil (using funnel again) about to the top of the bottle (I didn’t have enough to fill to the top, but it still worked fine). After a few minutes the oil will separate and settle above the water. Now add about 8 drops of food coloring into the bottle. Those will settle to the bottom as well.
Now comes the fun part. Break up the Alka-Seltzer into chunks and drop them one by one into the bottle. The chunks will fall down to the bottom of the mixture and mix with the purple water. The chemical reaction will take places and colored bubbles will begin to float up into the oil.
Now you can just sit back and enjoy the show. Keep dropping more and more chunks of Alka-Seltzer and you keep getting the same fun results. You can even put your bottle cap back on and keep this to do another day.
This activity is also a good chance to teach your kids about science. Here’s the science behind the homemade lava lamp: The oil stays above the water because the oil is lighter than the water or, more specifically, less dense than water. The oil and water do not mix because of something called “intermolecular polarity.” When you added the tablet piece, it sank to the bottom and started dissolving and creating a gas. As the gas bubbles rose, they took some of the colored water with them. When the blob of water reached the top, the gas escaped and down went the water.