All About Weather

Lesson Plan - Get It!

Audio:

The atmosphere determines what type of weather you will see in your part of the world on any given day.

The weather forecast is a prediction about what will happen each day in terms of precipitation and temperature.

• So, what exactly is weather?

Weather is the short-term temperature, precipitation, and other conditions in an area. It is important to note that weather occurs on a daily basis.

There are a couple of weather variables that you might have heard on the morning news. Wind speed and direction, precipitation, temperature, cloud cover, barometric pressure, and humidity are a few of the more common weather factors.

• Do you know what any of these terms mean?

Wind occurs when air moves along the earth's surface. Wind can be a light breeze or a powerful gust.

We can measure both the speed and direction of wind on the surface of the earth. A wind vane, or weather vane, moves based on the direction of wind in the area.

We record and report wind direction based on where it is coming from. For example, if wind is moving from north to south, we would say it is a northern wind.

Wind speed can be measured by a special tool called an anemometer. This instrument can measure wind speed in different units based on how quickly it is moving.

The wind catches the cups of the anemometer to calculate how quickly the air is moving.

Another important weather factor is precipitation.

Precipitation is the type of water that falls from the clouds, like rain, snow, and hail. It can range from a light drizzle that feels like a mist to a dangerous hailstorm producing hail the size of tennis balls!

Scientists measure the amount of precipitation so that we are able to track our fresh water supply for drinking. It also helps us notice changes in weather patterns over the years.

Another form of precipitation is snow, frozen droplets of water that fall during cold temperatures. If snow melts before it reaches the ground, it is called sleet.

Since snow is more solid, it can't be measured like rain. Scientists use rulers to determine how much snow has fallen in an area.

Hail is solid pieces of ice that fall and stay solid all the way to the ground. Hailstones can damage cars, crops, and other property.

The type of precipitation often depends on the air temperature. Temperature is based on the amount of heat in the air, and is measured using a thermometer. It can be measured in either Fahrenheit or Celsius units.

The amount of cloud cover, or clouds in the atmosphere, can impact the air temperature by blocking direct sunlight in an area.

The amount of cloud cover is reported as part of the weather forecast as cloudy or partly cloudy. Clouds can form quickly, so the cloud cover forecast may change throughout the day.

All weather occurs in the atmosphere of the earth, which pushes down on the earth's surface with great force. Atmospheric pressure is highest in places that have low elevation because there is more air pushing down than at the top of a mountain range.

When air pressure changes quickly, it can mean that severe weather is coming. Air pressure, or barometric pressure, is measured with a tool called the barometer, which measures pressure in a few different units.

Finally, weather forecasts generally include a report on humidity.

• What does an area with high humidity feel like?

Typically, the air feels very thick, and at times, even sticky.

Humidity is based on the amount of water vapor in the air, and can increase after a storm or rainfall. The air holds water vapor as it moves through the water cycle.

When the air has more water vapor, the relative humidity value is higher. Relative humidity communicates how much water the air can hold in comparison to how much water it is already holding. This value is measured using a hygrometer.

A hygrometer uses two thermometers, one with a wet end and one with a dry end, to measure the difference in temperature.

All of these tools are used to collect valuable information on the weather conditions in an area. With this information, individuals are able to make decisions about clothing and activity choices based on the weather forecasts.

Weather occurs in the atmosphere, and is felt on the surface of the earth. Weather is reported as the wind speed and direction, temperature, cloud cover, pressure, and humidity. Each of these factors provides a specific type of information about the conditions outside.

Summarize what you have learned about weather patterns and measurement tools in a graphic organizer or diagram. Then, share it with someone.

• Which of these weather measurement tools would be most useful for you to have on hand? Why?

Continue on to the Got It? section to quiz yourself on weather tools.