Build a Bridge That Holds a Can of Beans

There's a stack of flattened diaper boxes in my garage right now. Every week it gets taller. Every week I look at it and think about the Saturday, a few years from now, when Munchkin is old enough for the best rainy-day hour I know how to give a kid.

Two chairs. A pile of cardboard. A can of beans. One rule.

I'm a guy who builds things. Furniture, businesses, whatever's in front of me. And the thing I've learned building with my hands is the thing I want to pass on more than any skill: a problem you solve yourself is worth ten problems somebody solves for you. This activity is that lesson in a box. Literally.

The Setup

You need almost nothing. Two chairs, a foot apart, seats facing each other. Cardboard, and not nice cardboard: shipping boxes, cereal boxes, the diaper box. A roll of tape, any kind. Scissors. And one can of something from the pantry. Beans, corn, soup, doesn't matter. It needs to be heavy enough that a single flat piece of cardboard sags under it.

Put the can on the counter where she can see it. Point at the gap between the chairs. Say this: "Build something out of cardboard that goes from that chair to that chair and holds this can. I'll cut. You design."

Then stop talking.

The One Rule for You

You cut, she designs. That's it. That's the whole rule, and it's harder than it sounds.

She's going to lay one flat piece across the gap. It's going to sag. She's going to put the can on it anyway. It's going to fall. And every part of you is going to want to say "fold the edges" or "make a triangle" or "here, watch."

Don't. Let it fall. Let her stand there and look at the can on the floor and figure out what happened. The first collapse is where the actual learning is. If you skip it, you've built a bridge, but she hasn't.

What you can do is ask questions. "What happened?" "Where did it bend?" "What would make it stiffer?" You're not giving her the answer. You're pointing her at the problem. That's the difference between a dad who fixes and a dad who teaches, and kids can feel it.

What Usually Happens

Round one, flat piece, collapse. Round two, she doubles it up. Better, still sags. Round three she starts folding. Somewhere in here a kid figures out, on her own, that a folded edge or a rolled tube is stronger than a flat sheet. She won't know the word for it. She'll just know it works.

When it finally holds the can, don't celebrate yet. Get a second can. Put it on. If it holds, third can. Now she's not building a bridge, she's testing one, and that's a whole different kind of proud.

If it collapses under the second can, even better. Now she's got a bridge that works and a problem with it. "It held one. Why not two?" That's an engineer's question and she's asking it at six.

By Age

Four and five. She'll need more help than the rule allows. Bend the rule a little: you can fold, she tells you where. Keep the can light. One can is the whole win. Ten minutes might be the whole session, and that's fine.

Six and seven. This is the sweet spot. She can hold the problem in her head, she can use the scissors on the easy cuts, and she'll actually get mad at the can when it falls. Mad is good. Mad means she cares about the outcome.

Eight and up. Give her the scissors and step back further. Add rules: the bridge has to be at least this tall so a toy car can go under it. It can only use three pieces of tape. Whatever makes her think harder. Big kids will go an hour on this, easy.

Toddlers can't do this one, but they can do the version where you stack and they knock it down. I put that one in Activities for Dads and Toddlers.

What Goes Wrong

You take over. You'll see it happening. Her bridge is bad and your hands are already reaching. Sit on them if you have to. The moment you start building, she starts watching, and watching isn't the activity.

She quits after the first collapse. Some kids will. Don't push. Say "that one fell. Want to try one more way or are we done?" If she's done, she's done, and you try again in a month. The pressure to finish is yours, not hers.

The cardboard's too flimsy. Cereal boxes alone won't hold a can no matter how you fold them. Make sure there's at least one real shipping box in the pile so a solution is actually possible.

Nobody cleans up. Tape and cardboard scraps everywhere. Make cleanup the last step of the build, not a separate chore. "Bridge builders clean the site." She'll buy it.

Why This One

I could give you a hundred ways to kill an hour with a kid. This one's different because she walks away with something. Not the bridge. The bridge goes in the recycling by Tuesday. She walks away knowing that when a thing she made fell apart, she was the one who figured out how to make it stand.

That's the whole thing I want my kids to have. Not the answer. The habit of finding it.

If you want this card on your phone for the next rainy Saturday, it's in the activity generator. And if you're looking for more like it, I put together lists for sons and daughters, though honestly the bridge works on all of them.

Let's get it.

-- Gene, The Dad Post