 Hi everyone, my name is Jason. I'm a librarian here at San Francisco Public Library. For today's STEM challenge, I'm going to show you how to make sun prints. What makes sun prints a STEM challenge? Well, it has to do with science. And the way the sun's energy, the ultraviolet rays, affect the colors of the sun paper. What happens is some of the sun's energy travels to Earth as light waves. Certain light waves called ultraviolet rays have enough energy to change the chemical compounds of the sun paper. And those chemical compounds are the dyes and the colors in the paper. In this experiment, you'll see that the sun paper shaded by leaves and other objects causes it to have an imprint on the paper. So we're going to get started and here's what we will need. One sheet of sun art paper, one plastic sheet cover. You can use scavenge leaves, sticks or flowers or craft materials, which is what I'm going to be using. Ribbons, lace, yarn, anything like that that you have in a craft kit. You'll also need rocks or books or CD covers. Those are going to weigh down your plastic cover. And I don't have this today, but you will need a tub of water or access to a faucet. So what we're going to do is take our sun paper. We're going to lay that flat in direct sunlight and you're going to make a design on your sun paper. Anything you want, just throw it on. And once that's ready, you're going to take your plastic sheet cover and put it over the sun paper and then weigh it down with your rocks, your books or your CD covers. And you're going to let that sit in the sun between five and 15 minutes or until you can see the colors changing on the paper. Once that's done, just lift everything up and you're going to get kind of an image like this. And I made another one with leaves and other things. So what you're going to do next is you're going to put your sun paper in a tub of water or you can run it under a faucet for 30 seconds to a minute. And when that's done, you're going to see this kind of brighten up. Then you need to dry it so you can hang it on a clothesline with some clothespins or you can lay it on a towel until it dries. And once it's dried, you can lay it in a book and that'll help flatten it out so it's not so crinkly. And then you have a beautiful sun print. You can hang up. That's how you make sun prints.