S3.7.5 For the adult
Stretching and springs
If I hang twice as many stones on a rubber band, does it stretch twice as far?
What this chapter teaches
The stretch of a spring is the new length minus the original length. A spring stretches by equal amounts for equal loads until it is overstretched, but a rubber band bends away from a straight line.
Three questions to ask
There is no one right wording. Listen for the idea.
- How do you work out the stretch of a band?
- What would the graph of a spring look like, and why?
- Why is it better to measure than to guess the pattern for a rubber band?
After the chapter, the learner can
- Measure how far a rubber band stretches as you hang more stones
- Plot the results and describe the pattern
What they copy into their notebook
Stretch is new length minus original length. A spring stretches by equal amounts for equal loads, so its graph is straight. A rubber band bends. Measure and plot to see the pattern.