Pencaitland Primary Blog

We have been seeing how much a solid can be pulled or stretched before it breaks. We suspended a bottle from a broomstick using different materials and added water, a little at a time, until the material snapped. We learned that gravity pulls downwards on the bottle, creating a pulling force called tension, causing the material to stretch and eventually snap.  How quickly this happens depends on how thick the material is and what it is made of. We found that wool isn’t very strong but dental floss, which is very thin, was surprisingly strong.

Next we used clothes pegs to test the stretchiness of materials such as clingfilm, newspaper and paper towels.  We found that some materials are more elastic than others  - they stretch further before they break.

Joe - My arm got sore holding the brush, but I liked seeing the wool snap.

Rory - I’ve learned that some materials are stretchier then others.

Eilidh S - It was exciting waiting for the wool to snap.

Catherine - I liked stretching the clingfilm over the peg. The clingfilm didn’t snap.

Stewart - I liked adding the water to the bottle.  I’ve learned wool isn’t as strong as dental floss.

Henry - I liked seeing how the experiment worked out.  I learned about the force of gravity.

Declan  - I liked doing the peg experiment.  I found paper doesn’t stretch very far!!!

Corrie - I saw the wool got thinner just before it snapped.

Arran - I liked it when the bottle fell.  I saw that heavy things will snap the material more easily.