номер 4, страница 87 - гдз по английскому языку 8 класс (spotlight) учебник Ваулина, Дули

Science.

Across the curriculum. Five.

Exercise four. Page eighty-seven.

One.

Tornadoes.

Anytime, any place.

Tornadoes are one of nature's most violent storms and they happen in various parts of the world. They can form at any time of the year, although many occur in the spring.

Round and round.

A tornado is a spinning, whirling wind. When it meets with cold air, it takes the shape of a long funnel or tube, reaching down from a large cloud.

It is formed when warm air near the Earth's surface rises and meets with cold air. When the weather conditions are right, this warm air starts to twist as it rises, getting faster and stronger. It is a bit like watching water disappear down the plug hole in your bathtub.

If this huge twisting rope of air hits the ground, it may cause great damage. Tornadoes can reach speeds of more than two hundred and fifty miles per hour, ripping roofs from houses, uprooting trees, and tossing heavy objects like cars in the air.

Measuring strength.

In nineteen seventy-one, a meteorologist named Theodore Fujita developed a scale to show how strong tornadoes are.

His scale goes from F zero to F five. It doesn't calculate strength based on wind speeds, but the damage a tornado causes to homes and other buildings.

Two.

Hail.

Different sizes.

Hailstones are lumps of ice. They can be as small as peas or as big as cricket balls. In Kansas, USA, a hailstone fell that was forty-four point five centimeters across.

Getting ready to drop.

Hail is formed when raindrops start to fall. Before they reach the ground, they are blown up into the clouds again by strong winds. There, they freeze into balls of ice and the wind in the clouds bounces them up and down.

As the frozen raindrops rise and fall like this, they get even more thickly covered in ice from the water inside the clouds. Eventually, they get so heavy that they fall to the ground as hail.

Easy to hear.

When big hailstones fall, they make quite a noise, hitting roofs and pavements. Cars and buildings are damaged, and plants and crops are destroyed. Driving during a hail storm is also very dangerous, as the roads become slippery.