Rocket lets a marble roll down a book. Zip! It is gone.
"Too fast to watch!" Rocket says. "Let's slow it down."
Raven writes in her notebook. "What does slow mean? Let us pick a time."
Nova blinks. "Would you like a hint? Success needs a number."
Engineers split a problem into criteria and constraints.
| Criteria (what success means) | Constraints (the limits) |
|---|---|
| The marble takes 5 seconds or more | Use paper, tape and one big piece of cardboard |
| The marble rolls all the way by itself | No pushing the marble after you let go |
| The marble ends in a cup at the bottom | Start the marble at the top of the cardboard |
Criteria tell you when you are done.
Without them, you could build forever.
Our run is done when the marble takes 5 seconds or more.
It must also roll by itself and land in the cup.
| Rule | Allowed? |
|---|---|
| Use paper chutes and tape. | ? |
| Push the marble halfway down. | ? |
| Use one big piece of cardboard. | ? |
| Start the marble in the middle. | ? |
You defined the problem like a pro!
Tomorrow, we learn what moves the marble.