Rocket draws a lock with a row of pins inside.
"Now the key!" Rocket says, drawing bumps under the pins.
Raven looks closely. "What do you notice? Each bump has a pin."
Nova glows. "Would you like a hint? Make every pin stop at the same line."
Rocket fixes two pins. "Now it can turn!"
A cutaway shows the inside of a thing.
Today you draw the inside of a lock.
Show the pins, the springs and the key.
You slide the key in.
Each bump pushes one pin up.
The right key puts every pin in the right spot.
The lock turns. Click!
| Sentence | True or false? |
|---|---|
| The key's bumps push the pins up. | ? |
| Any key with bumps opens any lock. | ? |
| Springs push the pins back down. | ? |
| A lock is a machine with a job. | ? |
Next week we turn on a faucet.
A twist becomes a push that stops the water.
Watch a faucet handle turn before next Monday.
You explained a machine like an engineer. Wonderful!
Tomorrow is Machine Day with your family.