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Science Launch G3 / Week 04 / Thursday
4/6
Week 04 · Magnet Inventions

Thursday

Test and improve
// Solving problems with magnets
⏱ about 15 min

Thursday: Test and Improve

Raven and Rocket compare grabbers. Raven's magnet hangs on a short string. Rocket's hangs on a long, floppy one.

"Mine swings around too much," Rocket admits.

"What do you notice about how close each magnet gets to the clips?" Raven asks.

Nova scans both designs. "Remember what you learned about distance," she says.

Use science to improve a design

Engineers use science ideas to make designs better.

Magnet pull is strongest close up. So the magnet should get very close to the clips.

Magnets attract steel but not aluminum. So a magnet grabber can sort steel from foil.

Opposite poles attract and like poles repel. That helps some designs hold shut or push apart.

IMPROVE THE GRABBER
  • Read the question.
  • Tap your answer.
Rocket's magnet stops high above the clips. What change would help most?
A design must keep a box lid shut. Which magnet ends should face each other?
ENGINEERING STEPS IN ORDER
  • ?Draw and build a design.
  • ?List criteria and constraints.
  • ?Change one thing and test again.
  • ?Test it three times.
  • ?Say the problem.
WHY THIS EXERCISEEngineers define, plan, build, test and then improve.
StatementTrue or false?
A first design that fails is part of learning.?
Engineers change many things at once when testing.?
Science ideas can help improve a design.?
WHY THIS EXERCISEChange one thing at a time so you know what helped.

One change at a time

Rocket wants to fix his floppy grabber. He could shorten the string or add tape.

If he changes both at once, he will not know which change helped.

So he shortens the string first. He tests three times. Then he decides.

SMART CHANGES
  • Read the question.
  • Tap your answer.
Rocket shortens the string and his grabber lifts more clips. Why did it help?
Raven changes the string and the magnet at the same time. What is the problem?
Two magnets push apart instead of holding a lid shut. What should you do?
Magnet pull is strongest ____.
Like poles ____.
After a change, how many times should you test it? Type a number.
WHY THIS EXERCISETesting three times shows if the change really helped.
Design ideaWill it help the grabber?
Lower the magnet so it nearly touches the clips?
Hold the magnet high above the cup?
Use a short, steady string?
Swap the magnet for a piece of foil?
WHY THIS EXERCISEA close, steady magnet lifts more clips. Foil cannot attract anything.

Every test taught you something new. Tomorrow we look at real problems magnets help solve.

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