The method of making sun prints, or cyanotypes, was an early technique for creating photographic images or blueprints. Amateur botanist Anna Atkins used it to produce the first entirely photographic book, "Photographs of British Algae," published in 1843. But now you and your kids can use it to create cool artwork.
This craft requires special sun art paper that has been infused with a water-soluble chemical that reacts to sunlight. You can find it online or at art or photography stores. You will also need a shallow container of water, a clear sheet of plastic or glass, some random objects and the rays of the sun. The result will be white and blue art akin to a negative image.
You and your little ones can gather materials such as leaves, flowers, sticks, feathers or anything else with an intriguing silhouette. You can also use stencils or shapes you've cut out. Items that aren't flat will leave less distinct edges, but there is nothing wrong with experimenting. Before you go into the sun, arrange your items on the special paper and place a sheet of plastic or glass over them to keep everything from blowing away. Then take it all outside and leave it in the light. The paper should come with an acrylic sheet, but you can use picture frame inserts and the like if you don't want to be stuck doing one piece at a time. You can also pin the paper to cardboard to keep it in place.
After just a few minutes, remove the objects and place the paper in water for about a minute to wash away the chemicals. The area that was shaded by your objects will remain light and the exposed area will turn blue. You can add a little lemon juice to the water to turn the exposed areas a darker blue. Once the paper is dry, you can put it in a large book for a while to smooth it out. And then you can frame your art, hang it on the fridge or use it to create cards, stationery or other crafts.
There's also sun sensitive fabric that you can use to create clothing or fabric crafts. The sun printing method is similar, although you expose it for longer and rinse the fabric until the water runs clear.
If you do not have any sun paper, you can do something similar with construction paper, although it takes longer. Using a glue stick, affix stencils, leaves or other flat things to a piece of construction paper and tape or hang it in a window with the glued items facing outward. The exposed construction paper will fade after a few days. Peel off the items to reveal the darker silhouette left by your pasted shapes.