Reading 1

Unit 10- Reading 1

Page 146

Sun, wind and water

NATURE HELPS HUMANS

For all of human history, humans have depended on the powers of nature to help them survive. The sun warmed them and was a source of light. Rain filled lakes and rivers where they could obtain water to drink and catch fish to eat.

Sun and rain combined to help plants grow. The plants became food for the humans to consume. The plants were also food for the animals that humans hunted. Wind blew the seeds of trees and grasses to new fields. Wind filled the sails of small boats, so humans could travel on rivers or across oceans.

NATURE BRINGS DIFFICULTIES

However, sometimes nature did not help humans. In some years, the rain did not come. The hot sun baked the earth. Plants dried up because they had no source ot water. Hot winds blew the soil away, so future plants could not grow. This left humans without food to eat, and they starved.

In some years, too much rain fell. Homes were washed away when gentle rivers grew into potential killers. Often people drowned. Farm animals drowned. Towns disappeared in the flood waters. Similarly, the ocean was often a source of death.

Without any indication of danger, a giant ocean wave might suddenly sink boats. Likewise, a wave might approach land, where it washed away houses and drowned people. Powerful cyclones and hurricanes sometimes brought strong ocean winds over land. Sometimes they destroyed buildings, uprooted trees, and killed humans. The powers of nature have always affected human life.

HUMANS USE MACHINES

Then, about 200 years ago, humans learned how to create machines to help them do work. These machines needed fuel to work. Humans burned wood and coal to run the machines. They built steam engines to move ships and trains. They built automobiles and airplanes that were powered by gasoline engines. They learned how to produce electricity to light their homes.

They built washing machines and telephones and refrigerators and computers. All of these machines consumed fuels obtained from the Earth.

CHANGES IN CLIMATE

As the world population grew, so did the number of machines, and so did the use of fuels to power the machines. Recent scientific data indicate that the Earth is warming. The sun has melted ice near the North Pole and the South Pole.

The level of the oceans is rising. Cyclones and floods are happening more often. The concept of climate change worries humans.

Many scientists blame humans for this change in the Earth’s climate. They believe that humans have not used the fuels that we derived from nature in a good way. They believe we should instead use natural powers to produce energy.

They suggest that using sun, wind and water to produce energy will help preserve the Earth. The sun, wind, and water are considered renewable energy sources because they will always be there.

Ancient humans depended on the powers of nature to help them survive. Now modern humans want to use these powers to help them survive in today’s machine-based world.