Changing Steel: One paperclip at a time, by Aimee Goodall - for CoCoMAD 2020

Steel is in all of our everyday life, but did you know that the same piece of steel can act in two very different ways? We shall be using paper clips to investigate different methods of cooling steel and see how this changes the way it acts.

Equipment

• 3 paperclips (NO plastic coatings)

• Gas hob

• Non-magnetic pliers

• Bowl/cup of water (NOT plastic or paper)

• Ceramic Plate (NOT plastic or paper)

Safety

Note: There is hot metal and naked flames involved. Metal can remain hot longer than expected! Take care when handling

This should be carried out with care and attention

• Hot metal must only be handled with non magnetic pliers

• Metal stays hotter longer than expected, leave it longer than expected to cool

• Use a stable surface for bowl/cup and plate

• Bowl/cup and plate should not be made of plastic or paper

• Plate must be ceramic

• Gloves, safety glasses, long sleeves, shoes must be worn

• Hair must be tied back

• HEAT TREATMENT MUST BE CARRIED OUT BY ADULT

Method

Paper Clip 1

1. Straighten out the paper clip

2. Bend backwards and forwards till it breaks (be careful not to hurt yourself on the snapped end)

Questions: How easy is it to bend does it get more difficult to bend the long you do it?

Paper Clip 2

1. Straighten out the paper clip and hold using pliers

2. Place over gas hob for 10 seconds (it should glow orange)

3. Place on plate to cool (remembering to turn off hob)

4. Leave at least 2 minutes to cool down (get an adult to make sure it is cool to the touch)

5. Bend the paper clip backwards and forwards (be careful not to hurt yourself on the snapped end)

Questions: How easy is it to bend? Is it easier to bend than paperclip 1 was? How long does it take to break compared to paper clip 1?

Paper Clip 3

1. Straighten out the paper clip and hold using pliers

2. Place over gas hob for 10 seconds (it should glow orange)

3. Carefully place into cold water, you should hear a hiss (remembering to turn off hob)

4. It should have cooled after being in the water (get an adult to make sure it is cool and safe to the touch)

5. Bend the paper clip backwards and forwards (be careful not to hurt yourself on the snapped end)

Questions: How easy is it to bend? Is it more difficult to bend than paperclip 1 was? How long does it take to break compared to paper clip 1?

My Results

Paper Clip 1 – Not heated
More difficult to bend the more I bent it.

Didn’t take too long to bend.

Paper Clip 2 – Heated and cooled slowly
Easier to bend than paper 1

Easy to bend the material but take a long time to break.

Paper Clip 3 – Heated and cooled in water
Stiffer than paper 1 and more difficult to bend

Breaks quicker than paper clip 1 and 2