You will need:
- A rolled up metallic measuring tape
- Scissors
- Tape
Make a piece of jewellery with this experiment.
INSTRUCTIONS
- Roll out a bit of the metallic measuring tape and ask an adult to cut 20 cm from the tape with the scissors.
- The edges are sharp; before you proceed, gently wrap the edges in tapes.
- Now, try rolling the piece of tape backwards so that measurement side may be facing outwards.
- Open it up and try keeping it straight. Snap it on your wrist.
- Now try rolling the tape inwards so that the measurement side may be facing inside.
- Unravel the tape and try keeping it straight now. Is it possible to keep it straight?
RESULT
The metallic measuring tape is manufactured in such a way that when pulled out from the roll, the tape curves inwards. The bottom clear side is slightly broader than the top measurement side. This is done so as to keep the tape from rolling constantly. When the tape is deformed by rolling it downwards, the same technique is used as in the manufacturing process, making the tape bistable. This means that the tape now has 2 stable states. And moving from one stable state (which is the rolled up state) to the other (the straight state) the tape has to be straightened out. These properties are used not only in snap bracelets but also for remote handling nuclear stations.
