Sunday, 30 August 2015

Conduction: The magic balloon!

This is a really simple experiment and one that I've done loads of times before, I've just never blogged it.

 
 
Last week I showed the kids at Science Crazy Club how heat energy works and how it can be useful.

To demonstrate conduction I used a couple of experiments and this is one of them,

All you will need for this experiment is

  • 2 balloons
  • A candle
  • Some water
  • Goggles!

Now, I will fully explain the science of what is happening as I take you step by step through this very simple and easy experiment...

STEP ONE

Put your goggles on and light your candle.

 
 

STEP TWO

Blow up your first balloon and tie up the end.

STEP THREE

Place the balloon over the lit candle.

 

See how close it can get.  What happens?

It pops!

This is because the heat from the candle travels through the air and creates a tiny hole which makes the balloon pop!

STEP FOUR

Take a second balloon, fill it with 100ml of water.

STEP FIVE

Blow it up, with the water inside.  Tie it shut.

STEP SIX

Hover it over the candle like the previous balloon, do make sure that the flame is directed at the water filled part of the balloon.  How close can you get.  What happens?

  
The balloon gets warm but it doesn't pop!

Why?

CONVECTION

It's all about the water.  The water conducts heat, so as the heat rises to the balloon the water sucks, conducts, the heat away from the rubber of the balloon stopping it from bursting!



 

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