Module 5
PlanningGuide

Lab 2.3

Lesson 2.1
Lesson 2.2
Lesson 2.3
Lesson 2.4
Lab 2.1
Lab 2.2
Lab 2.3
Lab 2.4
Project 5

Physics Lab 2.3 Elasticity

Overview
The purpose of this laboratory class is to illustrate the relationship between the extension of a spiral spring and the force acting on the spring. We also increase the force on the spring to exceed the elastic limit.

Experiment 2.3.1 Spiral Spring

Equipment
Steel wire
Dowel
Soda can
Small spring
Needle
Drinking straw
A number of articles with similar weight. (e.g. coins, marbles, lead weights etc.)

Procedure

1. Make a small coiled spring by winding wire around a dowel.
2. Attach one end of the spring to a suitable support.
3. Arrange the spring in such a way that a pointer indicates the position of the lower end of the spring.
4. Construct a balance pan and attach this to the end of the spring.
5. Mark the position of the pointer and label this "0"
6. Place a weight (marble, coin) on the pan and mark the position of the pointer.
7. Place an additional weight on the pan and mark the new position of the pointer.
8. Remove the weights from the pan and check that the pointer returns to "0".
9. If the pointer does not return to its initial position, the elastic limit of the spring has been exceeded.
10. If the elastic limit has been exceeded, go to step 11 below - otherwise repeat the procedure starting at 6 above.
11. Place an additional weight on the pan and mark the new position of the pointer.
12. Repeat this 3 or 4 times.
13. Measure and record the distances between "0" and the marks for each additional weight.
14. Plot the distance from "0" versus the cumulative weight on the pan.

Results – Experiment 2.2

Extension of a Spiral Spring

Questions

1. Does the shape of the plot of distance versus added weight indicate that Hooke’s law is valid for the spring?
2. Was the extension of the spring proportional to the added weight after the elastic limit was exceeded?
   
   Answers