41. Why do leaves have different colors in the autumn
June 28, 2013
Why do leaves have different colors in the autumn?
When you look at a group of trees in the summertime, you see only one color: green. Of course, there are various shades of green, but it's as if it were all painted by one brush. Yet in autumn, these same leaves take on a whole variety of co...
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42. What gives flowers their scent and color
June 28, 2013
What gives flowers their scent and color?
Curiously enough, we often look at a plant and admire its "flowers" when we are actually not looking at the flowers at all! If we think of a flower as something brightly colored which grows on a plant, we may be quite mistaken.
For ...
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43. How do trees grow
June 28, 2013
How do trees grow?
Like all living things, trees need nourishment in order to be able to grow. Where does the tree obtain this?
From the soil, the tree obtains water and minerals. From the air, it takes in carbon dioxide. And the green of the leaves of trees harnesses the e...
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44. What is a seed
June 28, 2013
What is a seed?
One of the ways in which a plant produces another plant of its own kind is the seed. Just as birds lay eggs to reproduce their kind, the plant grows a seed that makes another plant.
The flower or blossom of a plant must be fertilized or the seed it produces...
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45. What is osmosis
June 28, 2013
What is osmosis?
How do plants take water from the soil into their roots? How do animals absorb digested food from the intestines into the blood vessels? After all, no holes can be seen in the roots of a plant or in the walls of animal intestines. The process by which this is done is called...
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46. What is chlorophyll
June 28, 2013
What is chlorophyll?
If you had to pick the one chief thing that sets plants apart from animals, what would it be? The answer is that plants are green. Of course, there are some exceptions, but this is really the one basic law of plants-their greenness.
Now, this greenness...
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47. What is cellulose
June 28, 2013
What is cellulose?
The softer parts of the bodies of plants are made up mostly of cellulose. It is the cellulose which enables a plant to bend and have flexibility.
Nearly all green, plants manufacture cellulose for their own use. It is made up of the same chemical elements...
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48. What are fats
June 28, 2013
What are fats?
Animals and plants have fats in their bodies which may be either solid or liquid. Most, but not all, animal fats are solid. Liquid fats are usually called oils, or more exactly, fat oils. But not all oils are fats.
All fats, solid or liquid, have this in common: They...
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49. What is chalk
June 28, 2013
What is chalk?
Practically no one can grow up in the world today without coming into contact with chalk at some time in his life. In millions of classrooms around the world, children step up to blackboards to write things with chalk. And, of course, what could teacher do without chalk to hel...
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50. What is rubber
June 28, 2013
What is rubber?
Rubber is as old as nature itself. Fossils have been found of rubber producing plants that go back almost 3,000,000 years! Crude rubber balls have been found in the ruins of Incan and Mayan civilizations in Central and South America that are at least 900 years old.
In...
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