Lately, we have been up to our ears in ocean animal books and projects and notebook pages. Apparently, it is a science subject that is going to stick around for a while. But that doesn’t mean that we can’t get sidetracked every now and then. Honestly, it’s one of the beauties of homeschooling. Your child suddenly shows interest in something, you go with it, and the learning happens! Not a bad formula in my book.
A while back, the kids and I participated in a “Brain Break” at one of our local churches. It is hard to explain a “Brain Break” in just a few sentences, but basically the church uses it as an outreach to the schools in the area. When there is no school because of a holiday or teacher in-service day, the church provides a full day of care for the students whose parents can’t afford to take off work for that day. They feed the kids breakfast and lunch, do crafts, games, activities, science experiments, and more. It is an amazing opportunity to serve others and to share God’s love with the kids. I got to serve in a room where we taught the kids how to make their own snow globes before doing a fun melting ice experiment with them. The experiment was a simple concept, but it held a definite wow factor for the kids. My boys had a chance to try the experiment at “Brain Break” too, and they talked excitedly about it all the way home. I decided we would replicate it at home. I thought of a few modifications that would make it even more fun, and that night I secretly filled up four balloons with water and put them in the freezer. The next day we popped those sparkling balls of ice out of their rubber casings and using salt and some food coloring, we conducted our science experiment and did a little art, too!
Want to get in on the fun? You will need: a balloon, water, a large bowl, salt, and food coloring or liquid watercolors. That’s it!
Fill your balloon with water, tie it off and put it in the freezer. (Tip: put your water-filled balloon in a bowl in the freezer so that it does not get lopsided or ridged from your freezer shelves.) Let it freeze in there overnight in preparation for the experiment. SCIENCE TIME: How does the water change from a liquid into a solid when it is put into freezing temperatures? You might already know that water is made up of molecules moving freely around, filling the space it occupies. Those molecules have three atoms each – two hydrogen atoms and one oxygen atom. When you put water into a place that is 32 degrees Fahrenheit or lower, the molecules stop moving so quickly. The cold slows them down. Eventually they slow down to an almost standstill. The oxygen atoms establish an organized pattern like crystals (remember those?), but the hydrogen atoms are rebels and go wherever they please. This is why water expands, or get bigger, as it freezes. If you put a bottle of water in the freezer with the cap screwed on tightly, it could explode from the water expanding as it freezes.
The next morning, put your frozen water balloon in a large bowl. (I have several colorful plastic bowls from the dollar store that we use for various occasions, and they worked perfectly for this experiment.) Use a scissor blade or knife to slit open the balloon and remove the rubber from your ball of ice.
Just doing this will produce some “This is so cool!” responses or whatever the kids are saying nowadays. Before we went any further in our experiment, I challenged the kids to hypothesize why there were these beautiful, sea-anemone-like structures inside our balls of ice. Gabi guessed that it was the flow of the water as I filled the balloons. David thought that maybe the water started turning to ice at the bottom and then moved out to the sides as it froze. SCIENCE TIME: Those were great hypotheses, but here’s the real reason for those crystalline structures inside the ice. It may have seemed that I filled my balloon completely with water, but as I tied it shut, there was some air trapped inside the balloon. If you look carefully at the first photo (the red one), you can see that the structure is actually made of hundreds of tiny bubbles strung together. Those bubbles are the air trying to escape while the water froze.
Now comes the fun part. Ask your kids to list some ways to melt or get rid of ice. The kids at “Brain Break” certainly had some interesting answers to that question! Inevitably, especially if you live in an area where snow and ice abound, someone will mention salt because they have seen it sprinkled on sidewalks and spread on streets during freezing winter weather. Salt is what is used in this particular experiment to melt ice. So scatter (don’t dump!) some salt over the top of the ball of ice. The next part is hard – waiting for a few minutes while the salt starts to do its thing. It’s a good time to discuss – SCIENCE TIME: How does salt melt ice? Here’s a quick video to explain it:
Or, if you want the Cliffs notes version, salt lowers the melting point of water. Its atoms of sodium and chlorine disrupt the hydrogen and oxygen atoms of the ice and cause it to slowly break apart.
You may not be able to see the melting of the ice initially. That is where your food coloring comes in. We used food coloring because that’s what I had on hand, but if you can get liquid watercolors, I would recommend that. Unless you like having rainbow-stained hands, then, by all means, copy us and use the food colors. Choose a color and carefully squeeze a few drops over the top of your ball of ice.
The salt actually sinks into the ice as it pushes aside the water molecules. When the color is added, it drips down into these little pockets left by the salt. This is clearly the art part! Wait a little while and then add a few drops of a different color. Try adding a little more salt. You will notice that after each time you add salt, the surface of your ball of ice will become more dimpled like a golf ball. It would take salt alone a very long time to melt this ball of ice. It works more on the surface, which is why it is used on icy roads and walkways.
Other factors are at work in melting the ice. Consider the temperature of the room you are in. Is the sun shining through the window and perhaps directly on the ice? Have you touched the ice at all with the warmth of your hand? Now leave your ice alone for a while. We went out to the library and the park before returning to see how our balls of ice were faring.
You can see that our ice now resembled alien brains, as Mikey pointed out. The tiny pock marks left by the salt had widened into larger pits like the finger holds on a bowling ball. The water trickled down the sides in a snaky fashion as it twisted and turned around all the salt holes. We added more color, which pooled up in the salt holes and streamed down the squiggly paths left by the melting ice. We again left it alone for a while and came back to see new designs and patterns etched into the ice. Each time we checked the ice, we were given a new art piece to admire and enjoy. The kids left out their ice all night, and in the morning they came out to see their bowls filled with dark, cold salt water.
It was such an enjoyable and educational experience that we want to do it again. What if we use something else beside a balloon to contain the water? What will happen if there are substances in the water before it freezes? What will the melting process look like if we use a hair dryer instead of salt? There are a great many more possibilities, and my little scientists are eager to explore this new world of solids and liquids with more experiments.