Lesson 2: Air Temperature and Pressure

Getting Started

Where do you think the weather cycle begins? It starts with the Sun and air. Today's activities explore how heat from the Sun affects the Earth's atmosphere and causes the weather we experience.

NOTE: You will fill in your weather journal for today during Activity 3.

Stuff You Need

  • Eyewitness Weather by Brian Cosgrove (revised edition)
  • 3 empty plastic bottles (juice, milk, soda) with their caps
  • glue or glue stick
  • hair dryer* (Activity 1 - optional)
  • marker
  • scissors

* - denotes an optional material that may or may not be needed

Ideas to Think About

  • What happens to air that is warmed or cooled?
  • How do convection cells work?
  • How do we measure air pressure?

Things to Know

  • Air pressure is a measurement of the weight of the air in the atmosphere pushing down on the Earth's surface.
  • A convection cell is the cycle of rising, sinking, and moving air due to temperature and air pressure.
  • A barometer is one of the oldest weather prediction tools; it measures air pressure.


  • Know that the Earth's atmosphere exerts a pressure that decreases with distance above Earth's surface and that at any point it exerts this pressure equally in all directions. (S)
  • Discuss and determine how the following are interrelated: temperature, convection currents, air pressure. (S)
  • Design and conduct investigations to demonstrate an understanding of scientific inquiry. (S)
  • Collect data to provide evidence for how the motions and complex interactions of air masses result in changes in weather conditions. (S)

Introducing the Lesson

Explain to your child that today she will find out how the Sun drives changes in temperature and air pressure and how these affect the weather. Weather affects the lives of every person on Earth. Note that your child will fill in the temperature, air pressure, and precipitation columns in her weather journal during Activity 3.
Reading and Questions
Materials: Eyewitness Weather by Brian Cosgrove (revised edition)
Read pages 6-7 and 16-17 of the book Eyewitness Weather by Brian Cosgrove. Then watch the video and read the short webpage at the following web links. The video explains four reasons why Earth has weather. The webpage explains how the Earth's spinning and revolution around the Sun affect weather. Then answer the questions.
Web Link
Web Link

  1. Name four reasons why the Earth has weather.
    Earth's weather is caused by the heat of the Sun, the atmosphere, water, and Earth's shape and patterns of movement as it orbits the Sun.
  2. In which layer of the atmosphere does our weather happen?
    Earth's weather happens in the lowest layer of the atmosphere, the troposphere.
  3. How does Earth's movement affect the weather?
    Answers can vary, but should include one or more of the following: seasons, day and night, wind currents, the Coriolis Effect.