What you’ll learn:
How to make gel window clings using chemistry and physics
Gelatins are powders of proteins that, when boiled in water, can create large networks of intangled proteins, which produces a hard gel. This gel can be colored and cut to create holiday window decorations.
Kids love to mix, mash, cook, and color. This is a great activity year round, but I love using at as one of my go to Thanksgiving activities because it keeps the kids busy, and it also makes cool holiday window decorations.
Personally, I can’t handle having my windows covered in gel clings year round. But there’s something about having colorful art on our windows in the dreary winter mornings that makes me really appreciate these jelly window stickers.
It’s easy, and fairly cheap, to make your own gel window clings. Read on to find the ingredients you will need as well as learn the process, and science, of this kid friendly STEAM activity.
How to make gel window clings and cool holiday window decorations
- Add 1 teaspoon of agar to 1 cup of cold water. You can double, triple, quadruple, etc this recipe if you want. 1 cup of water makes enough for about one child.
- Stir the agar in and bring the water to a boil
- Boil for 3 min
- Pour into a pan, dish, etc and allow to cool
- Use a straw to remove small circles of the agar gel
- Use the droppers to fill each hole with food dye coloring
- Wait for a day for the dye to absorb, then use cookie cutters to create shapes and stick them to the window
1. Add 1 tsp agar to 1 cup of cold water
You can likely stretch your agar further by adding more water. 1 tsp of agar should solidify up to 2 cups of water, however, this will change the firmness of your gel.
2. Stir the agar in and bring to a boil
It is important to stir the agar powder into cold water. If you put agar powder into hot water the proteins will instantly denature and form a big clump with themselves. We want a solution of agar proteins. As we heat these long stringy proteins they weave in and out of each other but don’t create new bonds as an egg frying does. The weaving of these long proteins thickens the water when heated, and lines up into twisted ropes when cooled, creating a 3-dimensional mesh net.
3. Boil for the agar for 3 minutes
You need to heat the gelatin to unravel the proteins. However, if you heat it for too long you will actually weaken or break these proteins, which means your gel won’t gel nearly as well.
4. Pour your gelatin into a pan, or mold and cool.
I use the base of these agar gels for a lot of projects, hands-on optics is one of my favorites (you can even make this gel tasty with Gatorade powder). I prefer to make enough solution to make 1/4 inch thick gel window clings. This gives you a lot to work with in terms of firmness, ability to color, and ease of cutting with cookie cutters.
5. Use a star to remove sections of agar
You only need to do this step if you want to color your holiday window decorations, but adding coor really does spark up your window clings. Once the gel has cooled you can use a straw to remove holes of the gel.
6. Use droppers to fill each hole
Now comes the art part! Kids can use food safe food dyes to mix up their own colors on a paint tin. Then let them use a dropper to place some dye in each hole. Each hole in the gel can have a different color. Over time, these dyes will diffuse throughout, coloring your gel window cling in fun patterns.
7. Wait for the dye to absorb and cut shapes
It takes a few hours for the dye to diffuse into the gel. This is a great activity to learn about osmosis and diffusion. You can also use it as a lesson in color mixing as nearby color wells will diffuse and mix into each other.
Once the dye has been absorbed you can use any shape of cookie cutter to create your gel window cling. Then just gently place it on the window! Now you have some great holiday window decorations!
Just be sure to remove the gel window clings from the glass after a week or so. If you don’t, they will dry there and be difficult to remove…speaking from experience on this one.
Update! Apparently, the Kitchen Scientist did this same project years ago! Check out their version which uses gelatin and glitter!