Taking Out Heat
When you put warm food in the
refrigerator,
it cools down after a few
minutes.
But the air inside the
refrigerator doesn’t feel
warmer. So, where does the heat
go ?
The heat doesn’t disappear. The
refrigerator removes it from the
food and releases it into the
room outside.
Inside a refrigerator, a special liquid (called a refrigerant) is used. This liquid can easily
change between liquid and gas.
Here’s how it works:
1.Inside the refrigerator: The cool liquid flows through thin tubes. It evaporates, turning into
a gas. As it does, it absorbs heat from the air and food, making them cooler.
2.Outside the refrigerator: The warm gas is pumped through coils on the back or bottom. Here, it
condenses back into a liquid, releasing the heat into the room.
3.The liquid then cools down and is pumped back inside to repeat the cycle.
This constant cycle of evaporation and condensation carries heat out of the refrigerator and
👍 It shows Newton’s third law of Motion (Every action has an equal and opposite
reaction)
Flatten the paper bag. Tape the straw along the
length of one side.
Decorate the bag to look like a rocket.
A Push in Two
Directions
Blowing up a balloon takes a lot of
huffing and puffing. But if you let the
balloon go, it zooms around wildly like
a rocket. What makes the balloon “fly”
like this?
Thread the string through the straw.
Then stretch the string between two chairs. Tie
the end so that the string is tight. Slide the straw
to one end of the string.
Place the balloon in the bag.
Blow up the balloon and hold the end so that no air
escapes. The air inside is pushing on all sides of
the balloon at once. So it doesn't move. Now your
rocket is read to fly.