Object Lessons on the Human Body eBook

This eBook from the Gutenberg Project consists of approximately 99 pages of information about Object Lessons on the Human Body.

Object Lessons on the Human Body eBook

This eBook from the Gutenberg Project consists of approximately 99 pages of information about Object Lessons on the Human Body.

Now let us put upon the blackboard something which will help us remember what we have learned about

ALCOHOL. 
DISCOVERED BY DESCRIPTION.  MADE FROM
Paracelsus.  Water-like; with a Fruits, Grains, or
pleasant odor; a Vegetables. 
CALLED hot, biting taste;
“The water of life.” and will burn with a
flame.

* * * * *

USES OF ALCOHOL.

We put some sugar into water; the children see that it melts; then some glue or shellac is placed in the same liquid; they see that this is not melted, but that, when alcohol is used instead of water, the glue or shellac is dissolved.  From this experiment they learn that alcohol is used in making varnishes.

Some water is poured into one saucer, and alcohol into another; a lighted match is applied to each; the class notices that the alcohol takes fire and burns, while the water does not.

Next, we fill a lamp with alcohol, and put a wick into it; when the wick becomes wet with the fluid it burns steadily and without smoke, as may be seen by holding a clean white saucer over the flame.  This shows why jewellers and others, who wish to use a lamp to make things very hot, prefer alcohol to kerosene, which, as the children know, smokes lamp-chimneys, or anything else, so easily.

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.

FACTS ABOUT ALCOHOL.  GOOD USES OF ALCOHOL. 
It melts gums.  To melt gums. 
Burns with a flame.  To make varnishes. 
Burns without smoke.  To burn in lamps. 
Will not freeze.  To make camphene, etc
Likes water.  To put into thermometer
Mixes with oils. tubes. 
                                To preserve meats, etc
                                To make perfumery. 
                                In making jewelry.

Copyrights
Project Gutenberg
Object Lessons on the Human Body from Project Gutenberg. Public domain.