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Grow It 3-5 / Week 07 / Friday
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Week 07 · Seeds on the Move

Friday

Think like an engineer
// How seeds travel to new places
⏱ about 15 min

Friday: Think Like an Engineer

Rocket grabs paper and scissors. "I will build the best paper seed ever! Right now!"

Raven holds up a hand. "Wait. What do you notice about how we tested before?"

Rocket thinks. "We planned first."

Nova hovers over the paper. "Engineers ask two things first," she says. "What must it do? What are the limits?"

A design problem

Engineers solve problems by designing things.

Tomorrow your family will design a paper seed that falls as slowly as possible.

A slow fall gives the wind more time to carry a seed.

Today you plan, like a real engineer.

Criteria and constraints

Criteria tell what the design must do to succeed.

Constraints are the limits you must work within.

Limits can be about materials or about time.

Criteria (must do)Constraints (limits)
Falls slowlyUse only paper and one paper clip
Lands without breaking apartBuild it in 15 minutes
Can be dropped again and againDrop it from the same height each time
CRITERIA OR CONSTRAINT?
  • Read the question.
  • Tap your answer.
"The seed must stay in the air a long time." Is that a criterion or a constraint?
"You may only use one sheet of paper." Criterion or constraint?
"You have 15 minutes to build." Criterion or constraint?

Many ideas are better than one

Engineers do not stop at their first idea.

They sketch several designs.

Then they compare which one best meets the criteria and constraints.

Nature has many seed designs too: parachutes, wings, hooks and pods.

Sketch two paper seed designs. Give one wings and one a parachute shape.
What a design must do is called the ____.
The limits on a design are the ____.
THE ENGINEER'S PLAN
  • ?Name the problem.
  • ?Build and test them.
  • ?List the criteria and constraints.
  • ?Sketch several designs.
  • ?Compare results and improve the best one.
WHY THIS EXERCISEEngineers plan, sketch, test, compare and improve.
Which nature seed design falls slowly with a papery wing? Type the tree.
WHY THIS EXERCISEMaple samaras have a wing that slows their fall.
StatementTrue or false?
Engineers should test only their first idea.?
Using only paper is a constraint.?
Falling slowly is one of our criteria.?
A fair test drops each design from a different height.?
WHY THIS EXERCISECompare many ideas, and keep the drop height the same.
Safety first
Sketching is safe for everyone.
Tomorrow, a grown-up does all the cutting with scissors.
Try it
Check your bean plant one more time this week.
Draw it in your plant log next to Monday's notes.

Fantastic planning, engineer! Tomorrow is Grow It Day. Your family builds and tests paper seeds together.

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