3. Contraction on cooling.
4. Malleability, ductility, hardness, brittleness, etc.
Exercises
1. Give an illustration of Hooke's Law from your own experience.
2. What devices make use of it?
3. Do solids evaporate. Give reasons.
4. When iron is welded, is cohesion or adhesion acting?
5. When a tin basin is soldered, is cohesion or adhesion acting?
6. Sometimes a spring is made more elastic by tempering and made soft by annealing. Look up the two terms. How is each accomplished?