How Strong Is
That String?

Idaho's Native Peoples
faced a problem.


Cordage was a wonderful material, but if it was being used as a net for catching rabbits in the winter, questions had to be asked. Was the net strong enough to hold a racing 10 pound rabbit? If the cordage in the net was not strong enough, the rabbit would break through. The consequence was no dinner, no warm blanket. Strong cordage was very important.

Other questions might be: Was dogbane or sagebrush the best material for making the cordage for the net? What about milkweed, was it better? Which material performed best in the cold of winter? The material used for the net was most important.

The problem has not changed. A new material is made, but how strong is it? How much load will it carry? How much work can it do? That is where the science of Engineering steps in with Materials Testing.

You can be an engineer and test your cordage for strength.

Follow these directions.

1. You will need a length of cordage. You can decide how long to make it.

Make your own cordage from plant fibers, such as dogbane.
Go to: Plants Index to decide on the best material for your cordage.

Go to: Cordage Production to review how to make cordage.

You can also make cordage from raffia. Raffia is found at most craft stores. You will need to soak the raffia in water.
Go to: Cordage Preparation to review the process of retting.

2. You will also need a spring scale.

3. Test your cordage by tying one end to the hook on the spring scale.

4. On the other end of the cordage tie a heavy weight. If you have scales, one of the weights from the scales will work.

5. The spring scale measures how much weight your cordage will hold.

6. Read the calibrated scale on the side. On a paper write note how much weight your cordage held.

7. Add more weight to the end of your cordage. Write down this new weight on your paper. If the cordage doesn't break, add more weight.

8. Keep adding weight until your cordage fails. That will be how much your cordage will hold, an indication of its strength and how much work it can perform.

9. Just for fun, test a length of cotton string that is about as thick as the cordage you made. How do they compare for strength?