Knowledge Power

Mushroom

Mushrooms often seem to appear as if by magic in a meadow after a rainy summer day.

The most familiar kinds look like little umbrellas.  Others may resemble bells, funnels, or pieces of coral.

Mushrooms belong to a group of plants called fungi.  There have neither flowers nor seeds.  New plants start from tiny cells called spores.

The spores are carried by the wind to new places in which to grow.  When a spore lands in a grassy meadow, it grows into a web of white threads.  The mushroom spawn lies inactive in the ground.  Then on a warm, damp day the mushrooms pop up for their brief appearance.

Growing at the top of tiny stalks, they come through the ground looking like small buttons.

They grow quickly into full-size mushrooms.  Their job is to scatter the spores which grow on the many thin ridges, called gills, underneath the mushroom.

Photo courtesy:  altopower

Mountain

Probably  you have noticed that it is usually much cooler in the mountains than in nearby lowland places.

This is because the higher  up you go, the less air there is above you.  The air becomes colder because it cannot absorb as much heat as it is able to hold at sea level.

Perhaps the next thing you discovered is that the climate may be quite different on one side of the mountain from what it is on the other side.

Mountains may block the wind or force it to rise so that it can move over the mountain tops.

As the air rises, it also grows colder, and cool air cannot hold as much moisture as warm air.  The moisture may be squeezed out in the form of rain or snow.

The wind becomes a dry wind by the time it reaches the other side, with the result that lower country inland may be a dry desert.

Mountains help store water.  During the winter months they collect water in the form of snow, which melts in the spring and drains off in rivers and streams.  They carry water to places that might otherwise get little or no moisture.

Photo courtesy:  wallpaperpimper

Light-year

Space is so vast that astronomers don’t use miles to measure how far stars are away from us.  The numbers of miles would be so large that you would have a difficult time using them.

Instead, astronomers use what they call “light-years” to measure great distances.  A light-year is the number of miles that light can travel in a year’s time.  Light travel very fast—about 186,000 miles every second!

If we multiply this speed by the seconds in a year, we find that it adds up to roughly 6,000,000,000,000 (six million million) miles.

Most stars are so far away that the light they give off takes several years to reach the earth.  For example, the nearest visible star beyond our sun.  Alpha Centauri, is a little over 4 light-years away, about 26 trillion miles.

When you look at this star, the light has been speeding toward you for more than four years.  The farthest stars may be billions of light-years away.

Photo courtesy:  antwrp

Silver Tarnished

Silver is a shiny, white metal.  But unless polished on occasion, objects made of silver may soon lose their brightness and become coated with a dull film.

When silver turns dark, we say it is tarnished.  Silver tarnishes for almost the same reason that iron gets rusty.  In fact, the word “tarnish” is used for rust formed on copper and other metals other than iron.

Tarnish is a form of corrosion caused by a chemical change when oxygen in the air combines or joins with the silver metal.  It forms a dark-colored film called silver oxide.  The tarnish helps protect the silver against further corrosion.

Soap and water will not remove it.  To make silver look shiny again, we have to use silver polish to remove the tarnish.  The silver polish changes the dark tarnish back to two separate elements, silver and oxygen—another chemical change.

Eggs and some other foods contain chemicals that can also cause silver to tarnish quickly.

Photo courtesy:  annecarolinedrake

Pagoda

A pagoda (pronounced puh GOH da) is a tall, tower like building found in many Asian countries.  Pagodas usually are used for temples and shrines.  They are made up of several tiers or stories, and are often richly decorated.

It is the Chinese and Japanese pagodas that most people know best.

The typical Chinese pagoda has eight sides and many stories.  Each story is shadowed by wide, tiled caves that turn up at the corners.  Small bells are often hung from the corners.  These will tinkle when the wind blows.

The different stories of a pagoda are symbolic and represent a journey from earth to heaven.  A tall spire is on the top of most pagodas.  Pagodas are often used as memorial buildings in China.  These unusual structures were first built in ancient India.

The idea of pagodas spread into China, Japan and other parts of Asia along with the religious called Buddhism.

Photo courtesy:  artlex

Bamboo

We usually think of grass as a small plant.  Some grass grows less than one-inch high.  Wheat grass may stand five-feet tall and corn frequently grows more than 10 feet tall.

Bamboo is a grass, too.  But unlike corn, wheat, oats, and other grass, bamboo grass may grow as tall as trees.  Some kinds of bamboo may grow rarely blooms.  Some have flowers just once every 30 years.  The plants usually die after they bloom.

New bamboo plants quickly grow from the seeds, which look like rice kernels.  The young bamboo plants may grow a foot or more a day.

In some countries, bamboo has many important uses.  A family may live in a bamboo house, sit on bamboo food in bamboo containers, eat tender bamboo sprouts as vegetables and keep chickens and other farm animals in bamboo pens.

Fishing poles, farts, buckets, bottles, paper and even tools are made from bamboo.

Photo courtesy:  straw

Evergreen

Many trees do not take a winter rest but continue to have green leaves all year round.  We call these trees “evergreen.”

On of the great dangers a tree faces in the winter is that of losing precious water.

Trees absorb water through their roots absorb little or no water.  And so, if the tree kept losing water through its leaves, the tree would dry out and it would die.

Many trees with broad leaves which lose more water, such as elms and maples, drop their leaves in winter.

Many evergreens, such as pines and firs, have tough, needle-shaped leaves that slow the loss of water.  They can withstand frost and drying winds.

Keeping their leave enables evergreens to manufacture food all year long, and to keep their green color.

This is one reason why the forests of the far north are mostly evergreens.

But evergreens do not keep the same leaves all their lives.  They shed old leaves a few at a time throughout the year.

Photo courtesy:  myopera