ZIMSEC O Level Combined Science Notes: Experiment: To compare the shear and tensile strength of sponge rubber and soft wood
Aim: To compare the shear and tensile strength of sponge rubber and a softwood
Materials: wooden ice-cream sticks/match sticks, pieces of sponge rubber, force meter
Method
- Twist the piece of ice cream sticks(poplar wood)
- Twist the pieces of foam/sponge rubber
- Attach the rubber on one end to the wall using bulldog clips and pull it using a force meter until it breaks
- Attach to the wall and pull the other end of the wood with the same force
Observation and results
- The wood snaps when it is twisted (subjected to shear force)
- The sponge rubber remains intact when it is twisted (subjected to shear force)
- The sponge rubber breaks in the middle when enough tensile/pulling force is applied
- Wood does not break when the same tensile force is applied
- It is very difficult to break wood by pulling and it
Conclusion
- Wood is strong in tension and weak in shear
- Sponge rubber is strong in shear and weak in tension
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