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Columns

Sent in by:
The ZOOMers

Can you stand on paper cups without crushing them?

## Materials Needed

• small paper drinking cups
• 2 cardboard squares 24" X 24" each
• small scoop
• sand

## Instructions

1. Check with a grown-up before you start this.
2. This activity should be done outside.
3. This is like Paper Cup Walk, but instead, we'll treat the cups like columns.
4. In Paper Cup Walk, we placed cups face down on a piece of cardboard. Then we put the other piece of cardboard on top and checked to see if it would support our weight.
5. This time, carefully cut the bottoms out of the cups. Do you think they will hold you up like this?
6. What if you fill them with sand? To do that, place the cup on the cardboard, and carefully pour the sand into the hole in the bottom with the scoop.
7. When you think you have enough columns, place the other cardboard square on top of the cups.
8. With a friend to spot you, carefully stand on the platform.
9. Did it hold you? If it did, try it with fewer cups. See how many cups you need to support you.

Here's why the paper cups supported you when they were filled with sand. There are two things going on. If you hold the sand in your hand, it spreads out. But, the sides of the cup prevent the sand from spreading out. To spread out, the sand would have to stretch the paper in the cup. But since the paper is strong, it's able to stop that. The paper is strong when you pull on it. This is called tension. It isn't strong when you push on it. It just folds in on itself.

The sand prevents the sides of the paper cup from folding in when you push down on it. The cups are like the columns of a building and the cardboard is like the roof of a building. When you stand on the cardboard, you put a heavy load onto the columns, pressing down on them. This is called compression. The columns are very strong when they're compressed and they hold you up.

Try using other materials to fill the cups, like pebbles or Styrofoam peanuts, and see how it works. When you're done, send your results to ZOOM!

Savannah, age 9 of Hackensack, NJ wrote:
It was very cool. I got to use only 7 cups to hold my wieght.

Kd, age 13 of Bracebridge, ON wrote:
It held me up with 2 cups and I weigh 105 pounds!! That's AWESOME!

Anny, age 14 of PA wrote:
When this experiment was done in my biology class, my 200-something pound teacher stood on 3 cups and didn't crush the paper cups.

Audry, age 13 of Albany, NY wrote:
It held me up with 10 cups. I way 110 pounds. Thats amazing!!!

Amanda, age 12 of Aliquippa, PA wrote:
I tried this and it held me up with 9 cups! And I'm 88 pounds! Thats so cool!

not yet implemented