Rocket holds up a drawing of a wagon wheel.
"I drew the inside, like Nova shows us!" Rocket says.
Raven looks closely. "What do you notice? Where is the axle?"
Nova glows. "Would you like a hint? The wheel turns around something."
Rocket adds a rod through the middle. "There!"
A cutaway shows the inside of a thing.
Engineers draw cutaways to explain how parts work.
Today you draw a cutaway of a wheel and axle.
You push the wagon.
The wheels roll along the floor.
The axles turn with the wheels.
Rolling makes less friction, so the wagon moves easily.
| Sentence | True or false? |
|---|---|
| The axle goes through the middle of the wheel. | ? |
| A wheel slides instead of rolling. | ? |
| A doorknob is a wheel and axle. | ? |
| A machine makes work harder. | ? |
Next week we zoom in on a zipper.
Tiny teeth and a slider do a big job.
Find an old coat or bag with a zipper.
You explained a machine like an engineer. Wonderful!
Tomorrow is Machine Day with your family.