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Everyday Machines / Week 08 / Wednesday
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Week 08 · The Refrigerator

Wednesday

Look closely at the seal and the walls
// A machine that moves heat out
⏱ about 15 min

Wednesday: Look Closely at the Seal and the Walls

Rocket opens the fridge door just a crack.

"The wall is so thick!" he says. "Thicker than my hand."

Raven points at the rubber strip. "What do you notice about the seal?"

Nova shows a cutaway. "Hint: what fills the gap when the door shuts?"

Insulation

Insulation is material that keeps heat from passing through.

It traps tiny pockets of air.

Heat has a hard time getting past those pockets.

Homes use insulation in their walls to keep heat out or in.

The seal

The seal is the soft strip around the door.

It presses against the fridge when the door shuts.

A tight seal closes the gap, so warm air stays out.

The seals should be airtight.

  • A fridge
  • Your eyes and one careful finger
  • A grown-up to help
Safety first
A grown-up stands with you at the fridge.
Open the door only a little, and only for a moment.
Do not pull or pick at the seal.
Never touch the back of the fridge or its coils.
Nothing is eaten during this lesson.
  1. Open the fridge door a little.
  2. Look at how thick the door is.
  3. Look at how thick the side wall is.
  4. Touch the seal softly. Is it soft or hard?
  5. Close the door and watch the seal squish.
SEAL AND WALLS
  • Read the question.
  • Tap your answer.
What does insulation do?
What does the seal do when the door shuts?
What does insulation trap?
Try it
Hold a thin sheet of paper up to a lamp.
Now hold a thick book up to the lamp.
Which one lets light through?
Thick walls block heat the same way.
SentenceTrue or false?
Insulation keeps heat from passing through.?
A tight seal lets warm air in.?
Fridge walls are thin like paper.?
Insulation traps tiny pockets of air.?
WHY THIS EXERCISEInsulation and a seal keep the kitchen heat out.
THICK OR THIN?
  • Read the question.
  • Tap your answer.
Which wall keeps heat out better?
The seal has a gap. What gets in?
What did Rocket compare the wall to?
Draw a fridge wall cutaway. Show the thick wall and the seal.

You looked closely at the walls and the seal!

Tomorrow, we test the seal and read a thermometer.

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