Testing strength and other properties

Polymers are very large molecules (sometimes called macromolecules).Each polymer molecule is a long chain of (mainly carbon) atoms. The polymers differ in their strength and one of the factors that decide the strength of a polymer is the width.

An experiment can be done to show this.

7-8 Polymer strips of different widths but the same length

2 identical stools An iron rod Mass holder hooks and masses

Place two stools approximately 20 cm apart. Place an iron rod over the gap between the stools. The diagram below gives some idea of how the set-

p should look. Fold the ends of the strips and tape them. Make holes in the folded ends to hang the mass

holder hook. Hang the first strip (one with the smallest width) in

the middle of the iron rod. Gradually add 100 g masses at a time to the mass

holder hook until the strip snaps. Add up all the masses and record your result. Repeat with the rest of the strips. Record all your

results.

In order to have a fair test, make sure that the length of all the strips is the same.

The only risk in this experiment is the falling masses when the strips snap.