Experiments with magnets and conductors
Densities of materials
The lb/gal column is used for comparison to a gallon of milk, which weights about 8.4 lb (it's mostly water). If that milk were changed to aluminum, it would weigh about 22.5 lb. If it were changed to gold, it would weigh about 161 lb (19 gallons of water)! Did you notice that copper is heavier than iron? A cubic foot of iron is 491 lb. A cubic foot of copper is 559 lb. Silver is even heavier than copper, at 655 lb for a cubic foot. Gold is really heavy at 1206 lb for a cubic foot. When you see a movie of thieves carrying bars of gold, you know they are faking it!