DIY lava lamp

I love to do fun little projects with my kids, and while Caleb is gone to camp, Jansen and I can choose some activities to do together.

Today's activity is based on science. Let's make a lava lamp!

The science behind a lava lamp is simple. We didn't use heat to elicit movement, we used salt. 

Because oil is less dense than water, the two will not mix and the oil will sit on top...no matter how many times you try to shake the bottle (as Jansen found out).

Once the salt, which is heavier, is poured in, it falls to the bottom of the bottle, carrying the oil with it. Eventually the salt will dissolve in the water, leaving just the oil to float back to the top. This creates the movement of the "lava" without needing heat. 

If you want to make your own, here's how you can do it:

You will need water, oil, food coloring, glitter (optional but fun), salt, and a clear bottle.

Fill the bottle about 2/3 full with water, then the remaining 1/3 with oil. Don't fill it all the way to the top to leave a bit of air for the mixing. 

Add your glitter and about 10 drops of your choice of food coloring. Jansen chose green. He loves all shades of green.

Close the cap tightly and invert the bottle a few times to mix the coloring into the water. Allow some time for the glitter oil to separate back on the top. 

Then pour in salt little by little and watch the "lava" move!

Jansen was totally into it. Simple, fun, free, and educational.

Here's a quick video of the lava lamp in motion...