The Parents' Review
A Monthly Magazine of Home-Training and Culture
"Education is an atmosphere, a discipline, a life."
"Two Simple Experiments in Botany for Children"
by C. Agnes Rooper
Various types of botany have been described from time to time in the Parent's Review, all having more or less for their object the importance of cultivating observation in the study of that branch as well as of all other branches of natural science. In this paper I propose to describe two simple experiments which prove visibly certain facts which otherwise are not demonstrated.
Plants are composed of a number of tiny structures to which the name of cells has been given. These cells are wonderful little laboratories where are elaborated starch, sugar, and carbonaceous, or popularly speaking, fatty substances of all kinds. These fatty substances are found in the cells composing the outer covering of fruits, and still more often in the cells of seeds where they are kept by the plant as a reserve store of food for its offspring. But it is not only to the plant that these fatty substances are of use, they are also of great service to man.
For instance, it is to them we owe the colza oil which lights our lamps, the opium which deadens our pains, the walnut oil and the oil of almonds which gives a relish to our food. To prove the presence of this oil in almonds is the object of my first experiment.
1. Take a piece of peeled pear or apple, cut it into the shape of a candle end, then carve the almond into the form of a cylinder pointed at both ends and stick it into the pretence candle end so as to represent its wick, put a light to it and it will burn for a brief space of time with a clear white flame. A termination may be made to the experiment by the operator swallowing the impromptu candle and the flaming wick.
Besides these fatty oils there are also found, in various parts of numerous plants, essences of oil called essential oils. They may readily be distinguished from the fatty oils by a simple process.
A fatty oil, if dropped on some paper, immediately makes a stain which spreads rapidly and cannot be removed, whilst a stain made by an essential oil quickly disappears by reason of its volatile nature.
From these essential oils most of our perfumes are manufactured. The petals of the rose, the violet, the heliotrope, the mignonette, and other sweet-scented flowers are impregnated with these oils. The plants of the family of the Labiates are many of them distinguished by their strong odour more ore less agreeable, such are the sage, the mint, the thyme, the rose-mary, etc., and the cause of it is the presence of essential oils in the hairs which cover their respective stalks and leaves. Each one of these hairs, instead of terminating in a point like those of a nettle, end in a little ball which is easily seen through a magnifying glass and is the bag which contains the oil.
Many fruits possess these essential oils, for instance the orange, where the presence of a volatile inflammable liquid may be proved by my second experiment.
2. Take a lighted candle, press any portion of an orange between the fingers a little distance from the flame, when a few tiny drops will be seen squirting out which will catch fire with an explosive noise and produce in the flame a kind of miniature fireworks.
Proofread May 2011, LNL
|Top||Copyright © 2002-2021 AmblesideOnline. All rights reserved. Use of these resources subject to the terms of our License Agreement.||Home|