Inside: Let’s play with ice marbles and find out what surface makes ice melt faster. It’s a great way to learn some science while having a lot of fun.
Ice cubes, especially colored ice cubes, have always been one of those things that all my kids love playing and learning with any time of the year. So when I came across sphere-shaped ice cube molds, I knew it was going to be a hit, and I was right.
“Ice play” is so easy to set up and keeps kids entertained for hours. It’s also very educational. Obviously, it’s great for learning the states of matter (liquid to frozen and back to liquid), but we also came up with a couple of delightful extension activities that I want to share with you today.
And don’t worry if you don’t have mold because it’s easy to make ice marbles with balloons. Just fill the balloons with water and place them in the freezer (or outside if it’s below freezing where you live). Once the water is frozen, just cut the balloon off with scissors, and voila! You have frozen marbles.
Frozen Marbles Experiment
What makes ice melt faster?
The idea for this experiment came to my eleven-year-old in a flash of very scientific inspiration. Watching the ice melt, he mumbled, “I wonder if the ice will melt differently in different rooms?”
I thought it was an excellent question, and we immediately put it to the test. My kids predicted that ice would melt faster upstairs than downstairs because heat rises: a logical hypothesis. But when we placed the ice in different rooms all over the house, we discovered that the ice in the kitchen melts way faster than in any other room. No surprise there: virtually anytime we are home, something is cooking on the stove or baking in the oven. And turned out that the ice in the office upstairs took the longest to melt. Heat does rise, but that room has five windows, so it’s the coldest and draftiest room in the house all winter long.
What surface makes ice melt faster?
The next natural question was whether the surface under the ice would impact the speed of melting. Let me show you how we set up this experiment.
What you need
Mold (or balloons)
Water
Food coloring (optional)
Our printable (optional)
Things from around the house that you can use as a surface for marbles (i.e., aluminum foil, parchment paper, plastic lid, small mirror, paper, something made of metal, etc.)
What to do
Make frozen marbles with your mold or balloons. Coloring is optional. We just can’t pass up the chance to look at beautiful bright colors.
Place frozen marbles on different surfaces. In our experiment, we used metal, wax paper, aluminum foil, and a mirror. We cut the wax paper and aluminum foil to exactly the same size as our metal coin.
We had to leave our small mirror as it was, but even so, I explained to my kids that in a lab setting, scientists try to keep all variables except one identical. This way, any changes in the results can be attributed to the change in that one variable or not anything else.
Talk about your predictions. Would the surface under the frozen marbles have an impact on how fast or slow it melts? Which marble will melt first? Last? Here you can introduce words like energy transfer and conduction if you want. You can read more about it below in the Science Behind the Experiment. Here is a printable for you if you wish to record your predictions and observations.
Keep an eye on them and a timer. Which one is the first to melt?
After 1/2 hour:
After 1 hour:
After 2+ hours:
When the experiment is over, you end up with a pretty piece of art. Or a big mess. It depends on how you look at it 🙂
The Science Behind the Experiment
All things are made of particles, including ice. All of the ice particles are closely compact. That’s why ice keeps a fixed shape: ice particles do not have enough energy to move.
When we take frozen marbles out of the freezer (or from the back porch), ice particles begin to gather heat energy from the air. The higher the temperature in the room, the more heat energy.
With each passing minute, particles in the frozen marbles move more freely and spread out. As ice changes from solid to liquid, it takes the shape of its surroundings – the surface of the table. It’s important to mention that even though the physical form of water changed, its molecules stayed the same. Water is H2O, whether it’s frozen or liquid.
However, it turns out that the temperature of the air is not the only thing that affects the rate of melting. The surface under the frozen marbles plays a role too. In our experiment, the marble on top of the metal coin melted first (even though it didn’t start melting right away), and the mirror was second.
Did you notice how it took the metal coin sample some time to show any reaction at all? At the half-hour mark, the ball that was on top of the metal was barely dripping, but it was the first one to melt completely. It turns out that energy goes both ways. Ice gathers heat energy from the air, at the same time as the energy is transferred to the ice cubes by conduction from the surfaces under them.
Metal is a better conductor of heat than other materials. You can see it in a simple touch experiment. Just pick a coin with your fingers at room temperature. Does it feel cool? That’s because your body is hotter than the room temperature. When you touch a coin, the heat from your body is transferred to the coin (in other words, the energy conducts away from your fingers into the metal). The result of this conduction is that it lowers the temperature of your fingers and that accounts for that sensation of coolness you feel when touching coins.
Parchment paper is a poor conductor of heat, which is why we use it in baking. Seasoned bakers tell us that parchment paper helps regulate the temperature and spread energy evenly over the entire surface (remember this next time you bake cookies!).
If you want to understand more about the science of heat transfer, read What is Conduction? from University Today.
Overall, activities like this teach kids many factors they might need to take into account when making predictions. Most of all, though, it taught my kids that to know anything for certain, you have to test it: something real scientists know all too well!
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