The first experiment is just a few cups of colored water and paper towels. We started with 6 plastic cups (but later added in a 7th) Two of the cups had blue water, tinted with food coloring, one was red and one was yellow. Then you will need 3 empty plastic cups. It is nice to have clear ones so you can watch the process.
Take the paper towels and fold them up into strips. Then put one end in the colored water and one end into the empty cup. You mill be mixing colors, so use primary colors that blend.
Yellow + Blue = Green
Red + Blue = Purple
Red + Yellow = Orange
The water will begin soaking up the paper towel and into the empty cups mixing the two colors together and making a secondary color. It takes a VERY long time, so tell your kids that this is something you will be watching all day long.
After several hours here is what we saw in our cups.
Later in the day, I had a brilliant idea to connect them all and make orange, too. I just added in one more cup and two more paper towels to connect them all together. I'm not sure why it took me half of the day to think of it, though...
My kids thought this was so cool. It started conversations about absorbing and also primary & secondary colors which is always great!
Here is the next simple idea to show absorption:
Get a paper towel and make some big circles of various colors on the bottom. You want to leave a little space at the bottom.
In a plastic container- I used a small clear plastic storage bin, but you could use a bowl, or whatever you have on hand- put a small amount of water, enough to just reach the bottom of the paper towel. You don't want the water level to reach the colors on your paper towel or it will make a swirly mess of colors. Believe me, we did that first. Place the paper towel into the water- just hang it over the edge.
The water soaks up the paper towel bringing all of the colors with it making a wonderful rainbow. My daughter who loves painting and colors was just so excited about this. She thought it was beautiful!!