Importance of Carbon Dioxide in the Air
We found that animals in breathing give carbon dioxide to the air. Also that it is added to the air in the burning of a candle. In the same way it is given off in the burning of coal, wood, oil, etc. As a result what do you [...]

How work and force are measured. We measure forces in terms of pounds or grams of force. The weight of a body is the measure of the force of gravity upon it. Force, however, may be exerted in many directions. An easy method of measuring a force is by the use of a spring balance. [...]

What is meant by work and force. We have already defined energy as the power to do work, but just what do we mean by doing work? A man who digs a ditch or shovels coal is doing work. Steam which moves a piston, which in turn operates a pump, which lifts water to a [...]

How wheels are used in doing work. Wheels are so commonly used in machines that when most of us think of machines and machinery, we also think of wheels. Like the lever, they may be used to gain force at the expense of distance or speed, or may be used to obtain speed or distance [...]

In engines in which the burning of fuel is the source of energy, there are other losses in addition to that due to friction. Suggest some of the ways in which energy in the form of heat is lost from a steam engine; also the gasoline engine. It has been estimated that in the steam [...]