Chemistry Demonstrations and Fourth-graders: A Volatile Mixture?

Last week, I attended the regional meeting of the National Science Teachers Association held here in Minneapolis. I enjoyed seeing so many enthusiastic science teachers attending the sessions and wandering around the exhibit hall.

But when did schools start hiring such young teachers? Nearly all of them were quite a bit younger than me. And I’m not that old!   I’m only … well, let’s just say that I’m a seasoned professional.

Instead of feeling old when I left the meeting, however, I felt young and inspired. I particularly enjoyed watching some of the chemistry demonstrations that presenters were teaching to the teachers. As we participated in these hands-on activities, I could sense the energy and excitement rising in the room. It was the same feeling I get when I put on chemistry shows in my children’s classrooms.

I even started thinking back to the first chemistry show I ever witnessed, when I was a fourth-grader at Meeker Elementary School in Ames, Iowa.

Several years ago I wrote up my memories of that chemistry show, and here’s a copy of that brief essay:

The magic of chemistry first reveals itself to me in 1965, during Spring Break of my fourth-grade year, when my family goes on vacation to the big city of Chicago. The highlight of the trip is the visit to the Museum of Science and Industry. As we amble through the museum, we learn about coal mines and submarines. We see a plastic human heart pumping red and blue fluid throughout a life-size model of a human body. We find out about all kinds of machines, from levers and pulleys to the internal combustion engine. And at 2:00 pm, we gather on bleachers in an open area near the lobby to watch a demonstration of “The Wonderful World of Chemistry.”


I’m seated in the front row. Facing us, on a little stage, is a long table covered with glass bottles of various shapes, sizes, and colors. Placed at one end of the table are a banana, a wooden board, and a pink rubber ball. The ball is exactly the same kind as one I use to play “bounce and catch” at home on my front porch.


The noisy crowd of parents and children quiets down as a man in a white coat steps behind the table and faces us. A red rose is pinned to his lapel. A bright blue balloon rises above him, held in his right hand. He’s wearing glasses that have little plastic shields on the side. This man sure has my attention.


He starts the show by pouring two colorless liquids together, turning them first pink and then purple as he says some magic words. As he mixes other liquids and solids, he creates smoke and fog, makes a volcano overflow, and sets off a loud explosion.


Finally, he tells us that it’s time for the grand finale. He still hasn’t touched the banana or ball. I wonder what he’s going to do with them; maybe he’ll give them out as prizes to kids in the audience. I could always use another pink bouncy ball.


He reaches below the table and pulls out a big metal container with a lid on it. He puts on heavy white gloves and uses a long set of tongs to lift the lid off the container. Fog rises from it. Using a metal scoop shaped like the ladle my Mom uses to serve punch at Christmas time, he scoops up some liquid from the container. We can all see that it’s colorless and bubbling. Suddenly he bends over and pours it on the concrete floor right in front of the audience. I can hear it splatter on the floor. I pull back away from it, just like everyone around me. We don’t want to get splashed with this mysterious bubbling liquid. But as soon as it hits the floor, it disappears. It’s gone. None of us got wet, but I did feel a puff of cool air.


The man in the white coat tells us that this liquid is called “liquid nitrogen,” and it’s colder than the coldest Chicago winter. Grabbing the blue balloon, he holds it down on the table and pours a scoop of liquid nitrogen over it. The balloon shrivels up like a huge raisin, making a crinkly sound as it shrinks. The man lets go of it, and it just lies there. But then, right in front of our eyes, it starts to grow, take shape again, and rise into the air.


Next, the man takes the banana. Holding it with his tongs, he lowers it into the liquid nitrogen container for half a minute. When he takes it out of the liquid, he grips it in his gloved hand, and he picks up the board and a nail. Using the “Banana Hammer,” he pounds the nail right into the board. We ooh and ahh and applaud. I guess he won’t be giving out that banana as a prize.


Finally, he reaches for the bouncy ball and drops it in the liquid nitrogen container. After a minute or so, he fishes it out using the metal scooper. Picking it up, he turns around and throws it at the concrete wall behind him. I get ready to grab it when it bounces back toward the audience. But it doesn’t bounce. It shatters into many small pieces. I wonder if he’ll put the ball back together as the grand finale, but it doesn’t work that way, I soon find out.


Before he leaves, however, he has one final demonstration for us. He unpins the red rose from his lab coat lapel, dips it in the liquid nitrogen, and then bangs it on the table. Tiny red pieces of frozen rose petals fly across the table. I’m not sure if I’m supposed to clap or cry. As everyone around me begins to applaud, I hesitantly join in. Even if the rose incident doesn’t sit quite right with me, I decide that chemistry is indeed wonderful, and I’m going to learn more about it when I grow up.

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Published in: on November 9, 2009 at 1:10 pm  Comments (3)  
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3 CommentsLeave a comment

  1. Hooray, hooray, hooray! Five thumbs up! Jane

  2. Not that old, eh? Happy (slightly belated) b-day! I enjoy your essays and commentary – Kirby

  3. I can already tell that’s gonna be super heplful.


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