We show a thermometer; the children are told its use if they are not already familiar with the instrument; we talk about the quicksilver in the tube, about its rising or falling according to the degree of heat or cold; then we inform the class that in
some countries where it is very cold quicksilver freezes; for this reason alcohol, which does not freeze, is colored red and put into the thermometer tube to be used in these Arctic regions.
Another use for alcohol is to keep or preserve substances. This we illustrate by placing a piece of meat into some alcohol. We explain that the water in the meat is that which causes it to decay. Alcohol has the power to take up or absorb water; so when meat is put into this liquid the water from the meat is absorbed by it, and the meat does not become bad. Those who wish to preserve insects a long time, and doctors who desire to keep any portion of a human body after death, put these into alcohol, in which they may be kept for a long time.
Lastly, we let the children smell cologne or other perfumery, and tell them this is made from different oils mixed with alcohol.
At the close of this lesson the class is ready to help us make the following BLACKBOARD OUTLINE.
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FACTS ABOUT ALCOHOL. It melts gums. Burns with a flame. Burns without smoke. Will not freeze. Likes water. Mixes with oils. |
GOOD USES OF ALCOHOL. To melt gums. To make varnishes. To burn in lamps. To make camphene, etc. To put into thermometer tubes. To preserve meats, etc. To make perfumery. In making jewelry. |
USES OF ALCOHOL—concluded.
You see alcohol is very useful for some purposes; but do people ever drink it? Some of the children think not, and we grant that no one is foolish enough to drink raw alcohol, because it is too strong. It would take only a little to make them drunk, and only a few ounces to kill them instantly.
We ask the pupils if they have ever seen a drunken person, and what made that person drunk? We soon obtain an answer,