LESSON 9.10 Why does the wind blow?
LEARNING INTENTION By the end of this lesson you should be able to: • explain how wind affects weather conditions • describe the role wind plays in changing weather • explain how wind patterns influence temperature and rainfall.
Tune in Wind turbines provide clean, reliable, renewable energy.
FIGURE1 Wind turbines generate clean, reliable and renewable energy.
1. Do you think using more wind turbines would be helpful in Australia? 2. List the positives and negatives of wind turbine use.
9.10.1 How wind influences weather The Earth’s atmosphere protects us from extreme heat and cold, creating conditions for life. The air in the lowest layer, called the troposphere , is where weather changes happen (see lesson 9.8). Air has weight. The weight of air above us pushing down on the surface creates pressure. If a barometer is tied to a hot air balloon, pressure readings drop as it rises because there is less air higher up. This is why mountain climbers and athletes find it harder to breathe at high altitudes.
SkillBuilder discussion Communicating 1. What is the current
FIGURE2 A barometer is an instrument that measures atmospheric pressure.
atmospheric pressure reading shown on the barometer?
2. According to the
barometer, what kind of weather can we expect based on the current pressure reading? 3. How does the barometer indicate changes between sunny, cloudy and rainy weather?
TOPIC9 Water in the world 309
Made with FlippingBook interactive PDF creator