Download WHAT IS WEATHER?

Reading Comprehension - Weather
Name: ___________________________________ Date: ________________________
WHAT IS WEATHER?
Everyone talks about weather, good weather and bad
weather, but how many people actually know what weather
is? If you were asked to describe weather, what would you
say?
Weather can be described as the state of the
atmosphere at a certain point in time and place. The
atmosphere is the blanket of air around the planet, and it
influences the weather that we notice. Weather can be hot or cold, wet or dry,
calm or stormy, and clear or cloudy. There are certain things that are involved in
weather, and these are: temperature, humidity, cloudiness, precipitation, wind
and pressure. Humidity is the amount of water that is present in the air in the
form of tiny water droplets. Precipitation is when water falls from the sky, either
as rain, snow, sleet, hail or freezing rain. Air pressure is the weight of the
atmosphere pressing down on the planet. You might not know this, but air
actually has weight! Air is made up of tiny little parts called air molecules, and
even though they are invisible, they still take up space. There are empty spaces
between the air molecules. When air molecules move closer together, air
pressure increases. Cold air weighs more than warm air, and the pressure of
cold air is greater than the pressure of warm air. This is because when air gets
warm the molecules move further apart from each other. All these things
together, temperature, humidity, cloudiness, precipitation, wind and pressure,
make up weather.
Let’s look at the atmosphere again. All the things we know as weather
happen in the bottom layer of the atmosphere called the troposphere. The
troposphere is about 6 to 10 miles thick. This isn’t really that thick when you
consider that the entire atmosphere is about 500 miles thick! Meteorology is the
study of changes in the temperature, wind direction, moisture (how much water
there is), and air pressure in the troposphere. People who study this are called
meteorologists. To predict the weather forecast for one day requires a lot of
work by many people and machines all over the world. Many instruments are
needed when studying weather and making forecasts: a thermometer measures
temperature, a barometer measures air pressure, a rain gauge measures the
amount of precipitation (rain or snow), an anemometer measures wind speed,
and satellites take pictures of clouds from space. Weather forecasts made for 12
and 24 hours are usually pretty good. Weather forecasts made for 2 or 3 days
are still good, but when forecasts are made for longer than about 5 days they
aren’t very accurate.
©2004abcteach.com
Reading Comprehension - Weather
Name: ___________________________________ Date: ________________________
Two basic things are needed to produce all of our weather: sun and water
in the air. These two things working together make wind, clouds, rain,
thunderstorms and hurricanes. The sun doesn’t heat the whole Earth the same
way. The Earth gets warmer when the sun is higher in the sky, or when there
are more hours of sunlight in a day. This is why the equator is warmer than the
poles, and why summer is warmer than winter. You already know that cold air is
heavier than warm air. As the sun heats the air, it rises. Colder heavier air then
moves into the space left by the warmer air, and this is how wind is created.
The air over land is often warmer than the air over the sea. When warm air over
land rises, cold air comes in, and that is why we get cold wind from the sea. Sun
combined with the water in the air produces clouds and precipitation.
Climate describes all the weather that occurs in a certain place over a
period of years. A description of climate includes average weather conditions
and regular changes in weather like the seasons. Climates tell us what a place is
usually like at a certain time of year, or all the time. For example, San Francisco
is said to have a mild climate all the year, while New Orleans has a hot climate.
Seattle has a rainy climate most of the year, and Phoenix has
a dry climate.
Weather is all around us all the time. It can change
from day to day and even from minute to minute, and now
you know what weather really is!
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Show what you know:
How is the weather today? Describe it, using some of the vocabulary words
from the article above.
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©2004abcteach.com
Reading Comprehension - Weather
Name: ___________________________________ Date: ________________________
Questions on Weather
1.
What are the 6 basic things that are included in ‘weather’?
a)
b)
c)
d)
e)
f)
2.
What is air pressure?
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3.
Which has greater air pressure, cold air or warm air? Why?
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4.
What is the troposphere?
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5.
What do meteorologists do?
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6.
What do you use to measure air pressure?
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7.
What does an anemometer measure?
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8.
How is wind created?
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9.
What is climate?
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©2004abcteach.com
Reading Comprehension - Weather
Name: ___________________________________ Date: ________________________
Answers to Weather
1.
a.
b.
c.
d.
e.
f.
temperature
humidity
cloudiness
precipitation
wind
pressure
2.
Air pressure is the weight of the atmosphere pressing down on the planet.
3.
Cold air has the greatest air pressure. The air molecules in warm air move
farther apart and air is therefore less heavy.
4.
The troposphere is where most of the things we know as weather, occur. The
troposphere is the bottom layer of the atmosphere, and is about 6 – 10 miles
thick.
5.
Meteorologists study the changes in temperature, wind direction, moisture and
air pressure in the troposphere.
6.
You use a barometer to measure air pressure.
7.
An anemometer measures wind speed.
8.
When the sun warms air it becomes lighter and rises. Cold air moves in to the
empty space left by warm air, and this creates wind.
9.
Climate describes all the weather that occurs in a certain place over a period of
years.
©2004abcteach.com