Subject: The Sciences—Steam • Group: Science • Class II • Time: 25 minutes
By Dorothy Chalmers
The Parents’ Review, 1909, p. 795
I. To demonstrate to the children the properties of steam.
II. To show by practical experiment the principle on which all steam engines are made.
III. To help the children to realize the simplicity of this principle and the wonderful results obtained from it.
Step I.—Remind the children of their last lesson by a few questions on the Fahrenheit and Centigrade Thermometers.
Step II.—Find out what they know about steam, and show by boiling water in a glass flask that true steam is invisible. What we see coming out of the flask is steam condensed by the cold atmosphere into watery vapour. By applying heat to the condensed steam change it again into true invisible steam. To prove that the steam is really there hold a spoon in the space and it will become moist.
Step III.—Ask the children what are some of the uses of steam (to work machinery); and explain by a diagram on the board how we utilize steam to work engines. Also demonstrate by a crank shaft with two rods.
Diagram—The Sciences, page 92.
Step IV.—Ask the children to recapitulate the lesson, and suggest the tremendous differences made to the world by the invention of the steam engine.