My mom finds the coolest things for the kids. Earlier this summer, she gave the girls this color changing nail polish made be Del Sol. You can find something similar HERE (amazon affiliate link).
Since blue is the Babes' favorite color and pink is Sweetie Pie's fav, that's what she got them. The blue is supposed to turn green in the sun,and the pink turns purple in the sun. The girls couldn't wait to try it out.
It's hard to tell in photos, but it actually does work. Blue nails are on the left, and green nails are on the right.
Pink nails on top, and purple nails on the bottom.
The girls also have some Del Sol flip flops where the straps turn from clear to pink in the sunlight. The Spencinator has similar ones that go from clear to blue in the sunlight. I think it's pretty cool. If you'd like to check out more of Del Sol's color changing products, you can go to their website HERE. (I'm not a Del Sol affiliate, I just think their products are cool).