Mar. 23, 2009

Alex and the Warm Toast

by Guest Blogger

My five-year old son Alexander and I have tried to get into the habit of doing one science experiment each weekend. But last weekend, faced with plenty of time on our hands and a couple of Spring days that were sunny but really cold, we decided to stay inside and do four experiments. Like science itself, they took a bunch of different forms.

The first experiment came from the book One Minute Mysteries: 65 Short Mysteries You Solve With Science. I read a riddle to Alex that essentially asked if you had to build the solar system using a collection of different-sized sports balls, which ball would you select to represent Jupiter? (Spoiler alert: the answer follows.)

Alex knew right off the bat that given Jupiter’s size relative to the other planets in the solar system, the ball would have to be bigger than a tennis ball. He ummed and aahed for a little while, then suggested a soccer ball. Then he withdrew that answer and instead went for a basketball. The book agreed.

After that, we did two really quick experiments – both from Pop Bottle Science: 79 Amazing Experiments And Science Projects -- still sticking with a solar theme.

In the first, we put a marble in a bottle and swirled it around, to demonstrate centrifugal force, one of the reasons why the Earth does not fly into the Sun. Then we tossed away the marble, filled the bottle with water, and positioned the bottle so that sunlight was shining through it, onto a blank sheet of white paper. The objective? To make a rainbow.

According to Pop Bottle Science, when sunlight hits water, the light bends and then separates into different colors. So we gave it a try. At first, we just had squiggly gray and white shadows on the piece of paper. But after a little bit of maneuvering, a tiny but utterly vibrant rainbow appeared on the paper, with each of the colors clearly visible.

Experiment Four came from the pages of The Magic School Bus In The Arctic. Alex loves The Magic School Bus series, which centers on a zany school teacher and a school bus that can transport kids into almost any situation.

Since the book was about staying warm in the Arctic, the purpose of the experiment was to figure out which material best keeps things warm. According to the instructions, we had to pick a number of different materials, and then wrap a slice of toast in each of them. After three minutes, we had to unwrap the toast, and see which slice had retained the most heat. For the materials, Alex picked cotton, plastic wrap, foil and paper. So we laid out a cotton napkin, and a sheet each of paper, foil and plastic wrap on our table. Then we cooked the toast, wrapped some in each of the materials and set the timer for three minutes.

While we were waiting, I asked Alex which material he thought would keep things warm. He said cotton. I thought it was more likely to be foil.

But when we unwrapped the toast, the results were surprising. The piece of toast that had been wrapped in paper was definitely the coldest. Then came the piece of toast that had been wrapped in plastic wrap. But the piece that had been wrapped in cotton and the piece that had been wrapped in foil felt the same.

Perhaps we had used a particularly efficient weave of cotton? Or our wrapping technique had not been consistent? It seemed so unlikely that cotton would have performed so well – even The Magic School Bus book advises folks not to go outside “dressed in a pillowcase.”

We will probably repeat the experiment in the future, to see if we get the same results. In any event, Alex was pleased that both the cotton and the foil got to share the limelight. “Do you know what?” he said, smiling. “The foil and the cotton both won!”

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