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Curling Metal: Doing Fun Science at Home during School Closures (Activity #21)

Follow along with a Science Buddies parent who is using family STEM activities to keep her kids learning at home during the COVID-19 school shutdown. New posts every Monday, Wednesday, and Friday. Today's adventure... exploring how heat expands aluminum foil.

Example of aluminum foil and paper strip being held over a flame and curling

Sensory Play as a Young Version of Materials Science

When my kids were little, they loved the sensory table at their preschools. From shaping playdough to building sandcastles and finger painting — the messier it was, the happier they were. In early education, sensory play is an activity that invites kids to investigate the world through their five senses. I have a slightly different take on it — I think much of sensory play is also an early introduction to materials science. Many of the traditional sensory play activities are also intuitive investigations of how materials behave. Through this kind of play, children come to understand that different materials have different properties. For example, through play, they learn that adding water to sand has a different effect than adding water to paper, that ice melts as it warms, and that playdough is stretchy.

There's no reason kids have to lose the fun of investigating materials as they get older! We can do similar types of activities, keeping the focus on playful fun and observing with all your senses, while also adding in science explanations about the cool behaviors of the materials we observe. Here are a few materials science activities to continue that sensory-kid-fun across a variety of ages:

  • How to Make Slime: this goopy, messy activity is fun for a variety of ages, from preschoolers to teens. Just vary the level of detail on the science explanation to match the age group.
  • Oobleck: A Recipe for a Mesmerizing Mixture: this preschool classic is actually a sophisticated material that has properties of both a fluid and a solid — even adults find it fascinating!
  • Curl Metals With Heat!: under the right conditions, you can use simple aluminum foil and a candle to investigate the thermal expansion of metals. This activity is good for upper elementary school through teens.
  • Candy Waterfalls: Can Candy Flow Like Water?: there's no sweeter way of learning about granular flow than to investigate which sizes and shapes of candy can move like water. Kids of all ages may enjoy the candy aspect, but the science in this activity is for kids in upper elementary school and higher.
  • Explore Glow-in-the-Dark Water!: every age will ooh and ahh over the fluorescing property of tonic water, but the explanation of why is best understood by middle schoolers and up.

My Pick of the Day: Curling Metal with Heat

A while back, I talked about having my children go through the list of activities and pick their favorites. The Curl Metals With Heat! activity was one that my son put on his list. I suspect it was the title that first intrigued him, and then watching the video clinched it:

How To Curl Metals With Heat

Since my son had the day off from online instruction, I thought this was the perfect day to try it. My second-grade daughter was keen to join in, too — probably because the activity involves a flame. This isn't the first fire-related activity we've done during quarantine. We tried the Candle See-Saw early on, and it was a huge hit. When we did that activity, I talked about my four rules for doing fire-related activities safely. I was thrilled to see that some of those safety rules stuck with my daughter; as we gathered supplies, she volunteered to get a glass of water "just in case we set something on fire."

Note: If you are doing a fire-science activity with your kids for the first time, I encourage you to first go back and read the ground rules our family uses to experiment safely.)

Once we had our supplies, the kids started measuring and cutting the paper and aluminum foil strips. This was easy for my seventh-grader, but my second-grader needed a bit of help with the measuring.

Three images showing student mesauring and cutting foil and paper strips for curling metal activity

Next came pasting the strips together to make different sets of two-sided strips.

Three photos showing student gluing aluminum foil and paper strips for curling metal activity

With one aluminum-aluminum strip and two aluminum-paper strips in hand, I let my son light the candle. We were careful to make sure the candle was on a nice thick wooden cutting board (I didn't want to risk melting the vinyl tablecloth we've been using for these science activities) and that the glass of water was nearby.

Before letting them try the experiment, I asked each kid to make a hypothesis about what would happen to the three different strips when held near the heat of the candle flame. With their hypotheses locked in, we started our experiments by holding the aluminum-aluminum strip over the flame. Nothing happened. This was not what my second-grader expected, and she immediately began to fret that the experiment wasn't working. I encouraged her to hang in there and see what happened with the other two strips before she made her conclusions.

My son eagerly jumped into the next set of experiments, and both kids were pleased and amazed to see the aluminum-paper strips curl either up (when the aluminum side is facing the flame) or down (when the paper side is facing the flame). Seeing this once was not enough! They continued to cut off the ends of the strips that had been curled and try again on a new section. A couple of times we got the paper to smoke a bit — and I'll confess that one time there were even a few glowing embers which were quickly extinguished by dunking the strip in the glass of water.

Example of aluminum foil and paper strip being held over a flame and curling

When I asked them why the curling they were observing was happening, my second-grader had no clue — but my seventh-grader got pretty close to the right answer. He knew it had something to do with materials expanding due to heat, and it only took a few leading questions for him to understand that we were seeing the aluminum foil expand more and more quickly than the paper.

This explanation did not hold my second-grader's attention, and she wandered off to play shortly after. Meanwhile, my son and I continued to explore and even went off-script a bit to see what would happen if we doubled up the aluminum-paper strips in different configurations. I won't reveal what we discovered — you'll have to try it yourself to see!

Overall this was a really cool, quick activity that I enjoyed doing as much as the kids did. The activity itself took less than 20 minutes, although the extra explorations my son and I did tacked on another 10-15 minutes. For my second-grader, the focus really was on observing what happened; the explanation was a bit above her level of understanding. In contrast, my seventh-grader found both the doing and the explanation fascinating.

If your kids try this curling metal activity or any of the other materials science activities , we'd love to see. Post a picture of what they make on social media and tag us. You can find us on Twitter, Facebook, and Instagram.

If this blog post was useful to you, please share it with other parents. Follow the links below to see what other science adventures we've been having at home.

View All Posts in this Series

A science activity log is available as a Word document or as a Google doc for online convenience. (Just choose "File/Make a copy" to save it to your Google Drive.)

About the Author

Sandra, Science Buddies' Vice President of STEM education, holds a PhD in Genetics from Stanford University and has spent the last twelve years working on science education and STEM outreach. Right now, she's stuck working from her home in the Pacific Northwest with her husband, second grader, middle schooler, and two oddly noisy gerbils. She hypothesizes her sanity will hold as long as she gets a daily dose of sunshine.

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