Melting ice with salt and then adding liquid watercolors is a simple kids' science experiment that we've done before. But sometimes you have to try something more than once to really get it right. Last time our melting ice science experiment was so much of a salt and watercolor free-for-all that we couldn't see what was happening to the ice under all the salt.
This time we got it right. And it truly is a beautiful and fun learning experience.
Melting Ice Science Experiment with Salt and Liquid Watercolors
MATERIALS
- Bowls or dishes (for making the ice)
- A large tray with sides
- Salt
- Liquid watercolors
or food coloring
- Droppers
or a spoon
INSTRUCTIONS
For fun, and for experiment's sake, I filled many different sizes of bowls with water and left them to freeze overnight. I recommend this!! Not necessarily the many part, but if you do this, try for 2-3 different sizes. And keep at least one of them shallow. The tupperware container you can barely see in the back of the photo above was great for this.
The next morning I loosened the ice from the bowls with a little warm water and set them in a big plastic finger paint tray with a lip (from Discount School Supply). I remembered how much the ice melted last time —it's the point, right?! —and didn't want a salty, painty mess all over my table. A baking tray with sides would work. I set our tray over an old towel for extra protection.
Maia's friend Stella was over for the morning and the three girls were very excited about the melting ice science experiment! I gave them each a bowl of table salt (the cheap Morton's salt) and they sprinkled it over the tops of the ice domes.
Two notes:
- Rock salt, or another coarse salt, would be good to try as well, but we didn't have any. (I did have some sea salt in the kitchen, but felt it was too expensive to use like this.)
- Also, I purposely gave them each a modest amount to sprinkle since I didn't want a repeat of the salt dumping excuse for a science experiment we had last time.
They got excited when they first noticed the little ravines down the side of the ice where the salt was melting it!
Once we could tell that the salt was melting the ice, I got out the liquid watercolors. I squeezed a little bit of a few different colors (yellow, pink, purple, turquoise) into jelly jars and added a dropper
to each.
Note: You can also use food coloring for this project. The color selection may be more limited, but it works just as well.
The girls squeezed the watercolors onto the ice.
Daphne had just as much fun with it as the older kids did, but it took her a few tries before she figured out the droppers (when to squeeze and when to release).
The color is beautiful on its own, but the real reason for adding the liquid watercolors is to highlight the ravines, crevasses, and tunnels that are forming in the ice as the salt melts it.
We talked about how the salt melts the ice, both before and during the science experiment. Since it was a hot summer day, we agreed that the ice would melt anyway. But then we talked about how salt makes ice melt differently. That it will melt ice at much cooler temperatures, and so wherever the salt touched the ice it would melt faster than the rest of the ice.
The swirls of liquid watercolors in melted ice water were beautiful, too!
In fact, we had A LOT of melted ice water. The girls took turns with a turkey baster to suction the water out.
You don't have to take the water out, but I thought it would be easier to see all the exciting tunnel action if the ice wasn't swimming in a lake. Also, our handy dandy plastic tray was cracked along the lip and I didn't want the water to reach that level. Plus the kids thought that using the turkey baster was as fun as the rest of the project.
Even Daphne had to take her turns with it!
Look! A colored ice suncatcher!
We took a few of our ice pieces out on the porch to look at them in the sunlight. The watercolors really helped to highlight where the ice was melting! We oohed and ahed for a while. They were beautiful.
From the bottom of the shallower ice pieces, you could see a whole bunch of tiny bubbles of color where the mixed salt and watercolors were pooled as they slowly ate away and melted the ice. We thought that was SO cool!!
After our break to admire the ice in the sunlight, we brought them back in and turned each over. We wanted to see what it would be like if we melted tunnels and ravines through both sides of the ice. So we added more salt (yes, there was some salt dumping action this time—mostly on Daphne's part), let it melt awhile, and then added liquid watercolors.
Note: Some of the salt (especially where it was dumped) had hardened into a solid mass. We chipped those away before adding the liquid watercolors, because we really wanted to be able to see the ice tunnels.
Just for variety's sake, we brought out different colors of the liquid watercolors: red, blue, and gold (the metallic gold paint was pretty amazing!).
I LOVED seeing how into this science experiment the girls were!
And the results were beautiful and interesting! You can see that the salt ate away at both sides of this ice piece so that there are holes through the middle.
We took all the ice outside and admired them in the front yard as they continued to melt.
This melting ice science experiment is one worth doing (and repeating). I hope you try it! And if you've tried it before, I hope you give it another go!
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