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Flashcards in Vocabulary Deck (34):

the force that air puts on an area

Air pressure


The tropical zone is the region that lies just above and below the equator, which is hit by the direct rays of the Sun. It is characterized by heavy rainfall and dense vegetation. The animals commonly seen here are animals like howler monkeys, elephants and tigers; snakes like boa constrictors; and birds like macaws, cockatoos, and toucans.



Celsius is a scale on which temperature is measured. On the Celsius scale, water is frozen at 0 degree and boils at 100 degrees



Cumulus clouds are white and puffy. They are made up of water droplets. They look like balls of cotton wool in the sky. Cumulus clouds are flat at the bottom and rounded at the top. These clouds can grow upward and develop into thunderstorm clouds.



You can predict the weather by looking at the clouds in the sky. Some clouds are formed high in the sky and look like feathers. They are called cirrus clouds. Cirrus clouds are white and made up of ice crystals. If you see these clouds in the sky you should expect a change in the weather.

Cirrus cloud


How does a doctor check if you have fever? He uses a thermometer to find how hot your body is. A different kind of thermometer is used to find how hot or cold a day is. A thermometer is a tool used to measure temperature.



A hurricane usually starts as a low pressure system over warm tropical oceans. As the intensity increases, it develops into a tropical disturbance. As the storm develops sustained winds up to 38 mph, it is classified as a tropical depression. Winds rotate in a counter-clockwise direction in the Northern hemisphere.

Tropical depression


Ocean currents are large scale movements of water in the oceans. Ocean currents can be warm or cold. The Gulf Stream cycles warm water from the Gulf of Mexico along the east coast of America, and further to northern Europe. This current keeps the United Kingdom in a moderate climate.

Ocean current


Sometimes you can see tiny dew drops on blades of grass and leaves. How is dew formed? When air is warm it can hold more water vapor. At night air cools down. When the temperature drops below a certain point some vapor changes to water. We see this water as dew. The temperature at which dew is formed is called the dew point.

Dew point


Hurricanes are storms that begin over the oceans. They bring heavy rain and strong winds. These winds can have speeds over 100 miles per hour! Hurricanes often destroy houses and pull out trees.



Deserts are located at the mid latitudes. They have extremely hot climates and less rainfall. The Sonoran desert is a rocky desert with Saguaro cacti and animals like snakes and lizards. The Sahara desert is a sandy desert having less or no vegetation. The camel is a hardy animal adapted to long periods of no water.



A typhoon is a severe tropical storm that originates in the Pacific Ocean, west of the International Dateline.



On a rainy day, wet clothes take longer to dry. Why does this happen? This is because air has a lot of water vapor in it. It cannot take water from the clothes as easily as on a sunny day. The amount of water vapor in the air is called humidity.



How does your teacher pick the best day for a field trip? She listens to the weather forecast. A forecast tells you what kind of weather you will have. Forecasts are made by studying things like temperature and wind direction.



Earth is surrounded by a blanket of air. This is called the atmosphere. Earth’s atmosphere is made of gases that help plants and animals to live and grow.



Sometimes, water droplets in clouds freeze. The frozen drops move up into the cloud, carried by strong winds. More ice begins to form on them. When they become too heavy, they fall as hail. Some hailstones can be as large as baseballs.



Sometimes hot and cold air meet in the atmosphere. The hot air rises above the cold air very quickly. Dark clouds form. Lightning flashes across the skies. These are followed by loud booms of thunder and rain. This is a thunderstorm.



Where does rain come from? Clouds are formed by tiny drops of water in air. When these drops get bigger and heavier, they fall to Earth. That’s where rain comes from.



Water vapor in air cools to form clouds. In clouds, small water drops come together to form bigger drops. When the drops become heavy, they fall to the ground as rain, snow, sleet, or hail. This is called precipitation.



Droughts are prolonged periods of little or no rain. Lack of rain can affect us in many ways.



You are enjoying a sunny afternoon at the beach. Suddenly, you see thunderclouds forming in the sky. How did this happen? The clouds formed when a mass of cool air runs into a mass of warm air. The area where these air masses meet is called a front. The weather can change very quickly at fronts.



Air masses form over large areas that have similar weather. A front is the boundary along which two air masses meet or collide. Different types of fronts bring different characteristic weather conditions. Recording and studying weather patterns makes it possible for meteorologists to forecast the weather.



When water is placed in a freezer, it becomes ice. As water cools, the molecules lose their energy. Their movement slows down and they finally freeze in place. The temperature at which water changes from a liquid to a solid state is its freezing point.

Freezing point


When a mass of cold air meets a mass of warm air, the cold air pushes the warm air up at great speeds. Sometimes this creates a twisting column of air, called a tornado. Tornadoes travel very fast. They can destroy anything in their path. Tornadoes are also called twisters.



Sometimes cumulus clouds move upward with rising air. As they rise, they become dark and big. They are now called cumulonimbus clouds. They are also called thunderclouds. These clouds can cause sudden and heavy rains.

Cumulonimbus cloud


Sometimes, when it rains, you see big flashes of light in the sky. Lightning superheats the air. Superheating the air causes a loud noise called thunder.



Is it raining outside? Or is it bright and sunny? The weather is what gives you an idea of how things are outside. It is a way to describe the outdoors at a given time and place.



Tornadoes are funnel-shaped clouds of air that stretch to the ground. Air spins very fast inside tornadoes. They can pick up things as they move along their path. Some tornadoes form over water. These are called waterspouts.



How does a weather man know when it’s going to rain? He measures the air pressure using a barometer. When the barometer shows low air pressure, the weather man knows that bad weather is on its way.



The Earth’s surface absorbs sunlight and heats up. Earth releases this heat in the form of infrared radiation. Gases in the Earth’s atmosphere, known as greenhouse gases, trap this infrared heat energy. The trapped heat makes life possible on Earth. Human activities lead to an increase in the emission of greenhouse gases. As a result, more heat gets trapped resulting in the Earth’s climate gradually getting warmer.

Global warming


Temperature is a physical property that measures the heat in an object compared with a standard. In substances with a higher temperature, molecules have greater average kinetic energy. As temperature decreases, the average kinetic energy of the molecules also decreases.



The atmosphere is made up of layers of gases. These layers of gases push down on Earth. This push is called barometric pressure.

Barometric pressure


Thunderstorms can make a funnel-shaped column of clouds. This column stretches down from the sky but does not reach the ground. When funnel clouds touch the ground, they are called tornadoes

Funnel cloud


Climate is a description of the average weather conditions in a region over a long period of time. A desert has hot and dry conditions, while a rainforest is warm and wet.