Weird Science: DIY Lava Lamps

We straight up stole this idea from a buddy of ours who had a rad science birthday party recently. It's simple with supercool results. And a good experiment in density, too. You don't need the light, but we liked to try and make it as close to a real lava lamp as we could (although the lights we used float, so it wasn't exactly the same).

Here's what you'll need:
*a tall bottle (a plastic water bottle works great);
*cooking oil (enough to fill up 3/4 of the bottle);
*water;
*food coloring;
*alka-seltzer tablets; and
*small submersible lights (we used these fairy lights -- you could also hold a flashlight under the bottom of the bottle)

Fill up the bottle 3/4 of the way with cooking oil. Fill the remainder with water, but not quite all the way to the top (you'll need some room for bubbling action). Add a few drops of food coloring (if you use gel food coloring, color the water first -- we made that mistake the first time around). Break up the alka seltzer tablet and drop it in a bit at a time. As the alka seltzer releases small bubbles of carbon dioxide, the bubbles rise up and take some of the colored water with them. If you are using a light, go ahead and add it now.

We waited until the bubbles stopped, put the tops back on (make sure to keep the top off until the bubbles are done or you'll get a nice little explosion), and took them into our cardboard box "tree house" we made that afternoon. With all the lights off, they were great lamps to light the market we were running in there.

OH, you might have noticed we are in the process of coming up with a new topic organization scheme -- our "In Home Entertainment" category is getting a little heavy! We'll get it together ASAP.