I found this glow in the dark chalk kit at Michael's (craft store). I really wish I knew how to take good pictures in the dark, because these photo's totally don't do the experiance justice. It was SO fun for Elle! Super easy, just mix a couple things together, pour into plastic mold and it hardens in about 30 minutes.
I will say that it didn't hold together very well, but maybe I put in too much water... but Elle didn't care, she enjoyed how it all fell appart and she could basically finger paint with it.
We had to play with it under Elle's "tent" (a whole other story I will have to post) on the porch for the effect since there are so many lights here that it never gets dark outside.
The stuff glows for about 4 hours (according to the box, we didn't stay up to 2am to find out...) It was pretty funny though how we all glowed. You really learn how much you touch when whatever you touch then glows. Great lesson on germs for kids! =)