I Taught My Kid Simple Machines Last Weekend And Didn’t Even Mess It Up That Bad
It was 7:45 PM Friday, I was still in my wrinkled work sweatpants, there was half a bowl of soggy Cheerios on the counter, and my 10-year-old slumps into the kitchen holding a crumpled neon pink flyer that says “3rd Grade Science Project: The Six Simple Machines, due Monday.” I stared at it for a full 10 seconds and realized I couldn’t name more than two. Lever, and… wheel? Something? I didn’t want to admit I’d completely flushed this unit from my brain after 8th grade, so I just nodded and said “Sure, we can knock that out this weekend, no problem.” Which is the kind of lie parents tell that always comes back to bite you, but this time it actually ended up being kind of fun. Messy, but fun.
We started Saturday morning over burnt toast, and I’ll admit I had to Google the full list first. No shame in that. Turns out there really are just six, that’s it, all machines everywhere are just combinations of these six. We decided not to just copy boring textbook diagrams, we’d find examples in our actual house and neighborhood, which was the kid’s idea, honestly. That’s when it got interesting.
First up was the lever. I immediately yelled “see-saw!” which is correct, but boring. We were still standing in the kitchen, and the kid couldn’t open the strawberry jam I’d just bought because the factory had cranked the lid on way too tight. He grabbed a butter knife, jammed it under the edge of the lid, pushed down with his thumb, and pop! Lid came off, got jam all over my wrist. Wait a second, I said. That’s a lever. It pivots on the edge of the jar, amplifies the little force from your thumb, pops the lid right off. I didn’t even think about that before. We still have a pinkish splotch on the linen tablecloth from when I knocked the whole jar over mid-explanation. No use crying over it, I’ve already accepted that all my nice cloths have permanent stains at this point.
Next was wheel and axle. Duh, bikes, toy cars, skateboards. But then I realized the doorknob on the pantry door? That’s a wheel and axle too. The big round knob is the wheel, the little rod that turns the latch is the axle. Turn the big one easy, it moves the small one to pop the latch open. The kid immediately tested this by turning the knob and sneaking a chocolate chip cookie out of the jar I hide behind the flour. I let it slide, science first, right?
We went for a walk after that to get out of the house (jam crumbs everywhere), and that’s when we talked about inclined planes. It’s just a ramp, duh. The curb cut on the corner by the bus stop is an inclined plane. The slide at the park is an inclined plane. The kid remembered when we re-did the front garden two weeks ago, and we had to haul gravel from the pickup truck. We propped an old 2×4 between the truck bed and the ground, rolled the wheelbarrow up it instead of lifting the whole heavy thing. “That’s an inclined plane, right?!” he yelled, right as he was running up the slide. I almost tripped over a stray dog toy on the way to catch him when he slipped on the wet plastic. Got a scratch on my shin that’s still there. “Cool,” I said. “You got it.”
Wedge was the one I always mixed up with lever for some reason. It’s just two inclined planes put together, right? It cuts or splits or holds stuff in place. I grabbed an apple from my bag, cut it with a pocket knife, and said the blade is a wedge. Pointy at the end, spreads the apple apart when you push it. Then we saw a rubber doorstop holding the park bathroom door open, that’s a wedge too! It doesn’t have to cut, it can just hold stuff where you want it. When we got home, I hung his new T-Rex poster on his wall with a nail, and I pointed out the pointy end of the nail is a wedge. It splits the drywall apart so you can hammer it in. The hole’s crooked, so the poster tilts like 15 degrees to the left, and I haven’t gotten around to re-hanging it. He doesn’t care, so I don’t either.
Pulley was the one I messed up the explanation for at first. I said it’s for lifting big things with rope, like construction cranes. Then I looked up at his bedroom window blind, the one with the pull cord. That’s a pulley! The little wheel at the top that the cord runs over lets you pull down to lift the blind up, which is way easier than reaching all the way to the top to pull it up yourself. And speaking of messing up, that blind’s cord broke three weeks ago when I pulled too hard trying to get it unstuck. I spent an hour watching YouTube videos trying to restring it, gave up, and now we prop the bottom of the blind up with his giant stuffed rabbit when the morning sun is too bright. Perfect functional pulley demonstration, honestly. It works, sort of.
Last was the screw, which blew my mind a little. I always thought a screw was just the metal thing you drill into the wall. But turns out it’s just an inclined plane wrapped around a center stick. And what’s the most common screw we use every day? A jar lid! That’s right, the spiral ridges on the inside of a jar lid are just the inclined plane wrapped around. Twist it on, it pulls the lid down tight, no slipping. That’s so cool, I never thought of a jar lid as a machine before. The kid also pointed out the base of a light bulb is a screw, which is right. And the adjustable height on his step stool that he uses to brush his teeth, that has a big screw to hold it at the right height. Neat.
After that, we glued all our little notes and doodles to his poster board, he labeled each one. He forgot to color the screw drawing, so he got a B+ instead of an A. He didn’t care, I didn’t care. What I thought was gonna be another stressful weekend homework chore turned out to be kind of a nice day. It’s weird, right? You walk past all these things every single day, never think twice about them, and suddenly you realize every doorknob, every jar lid, every doorstop is one of these six basic little machines, all working together to make your life easier.
I haven’t thought about simple machines since I was sitting in 8th grade science, copying definitions off the chalkboard. I never got any examples that mattered then, not like prying open a jam jar or propping open a door with a rubber stop. It’s not fancy, it’s not some big life lesson. The stain’s still on the tablecloth, the poster’s still tilting on the fridge, the blind’s still propped up with a stuffed rabbit. That’s just how it goes. Some science lessons stick better when they’re a little messy anyway.
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