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

Tuesday

Heat moves from warm to cool
// A machine that moves heat out
⏱ about 15 min

Tuesday: Heat Moves From Warm to Cool

Rocket holds a cold spoon from the fridge. "Brr!"

Soon his hand feels cold and the spoon feels warmer.

"The cold went into my hand!" he says.

Raven shakes her head. "What do you notice? Which one is warmer?"

Nova glows. "Hint: heat moves. Think about where it goes."

Heat always moves one way

Heat is energy that moves from warm things to cool things.

It always moves from the warmer thing to the cooler thing.

Rocket's warm hand gave heat to the cold spoon.

The spoon got warmer. His hand got cooler.

Heat keeps moving until things match

Heat keeps moving until both things are the same warmth.

Then the moving stops.

A cold drink left out slowly warms up to room warmth.

WHICH WAY DOES HEAT MOVE?
  • Read the question.
  • Tap your answer.
A warm hand holds a cold spoon. Where does heat go?
Heat moves from a warm thing to a what?
When does heat stop moving between two things?

So how does a fridge stay cold?

Warm kitchen heat leaks into the cold fridge.

That would warm the food up.

So the fridge moves that heat back out.

It pushes the heat out the back into the room.

That is why the back feels warm.

Try it
Ask a grown-up for a metal spoon.
Hold it in your hand for one minute.
Does the spoon feel warmer now?
Where did that heat come from?
Safety first
Use a plain spoon at room warmth, not a hot one.
Nothing is eaten during this lesson.
SentenceTrue or false?
Heat moves from warmer things to cooler things.?
Cold moves into your hand from a spoon.?
A fridge moves heat out into the room.?
The back of a fridge is warm because heat leaves there.?
WHY THIS EXERCISEFollowing the heat explains the cool front and the warm back.
FOLLOW THE HEAT
  • Tap a card.
  • Then tap its spot.
1First
2Next
3Then
4Last
HEAT DETECTIVE
  • Read the question.
  • Tap your answer.
A warm cup sits on a cool table. Where does heat go?
Ice sits in a warm room. Where does heat go?
Does a fridge make cold or move heat?
Draw Rocket's hand and the spoon. Draw arrows showing where heat moves.

You followed the heat like a real scientist!

Tomorrow, we look closely at the door seal.

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