3.3 Answers

LC p.215 2. Explain why the Sun is the most important influence on Earth’s climate. The Sun is the most important influence on Earth’s climate because the Sun’s solar energy is responsible for the temperature on our planet.

LC p.215 3. Use figure 3.9 to explain why it is warmer in the northern hemisphere in summer than during the other 3 seasons. In the northern hemisphere in summer, Earth is tilted toward the Sun. The angle allows for solar energy to strike the region more directly, causing warmer temperatures than in the other three seasons.

LC p.217 Explain why the atmosphere is a heat sink. The atmosphere is a heat sink because it traps and stores heat and allows it to even out the distribution of heat over the day.

LC p.217 2. Use figure 3.11 to explain how the warming and cooling of air generates wind. Wind blows, heating the air. Warm air will expand and rise. As it rises, it causes wind to form. The wind rises but cools as it reaches higher latitudes. The air cools down and then sinks. Cool air is attracted to heat, so it moves as wind to warm areas, staring the heat transfer cycle again.

LC p.217 3. Explain why Earth receives more direct energy at lower latitudes than at higher latitudes. Earth receives more direct solar energy at low latitudes than at higher latitudes because of the way the Earth is tilted

3.3 More Answers

LC p.219 2. Predict what would happen if the concentration of greenhouse gases in the atmosphere increased. Predictions may vary. For example: If the concentration of greenhouse gases in the atmosphere increased, the Earth would become very hot. Vast deserts would form, and plant and animal life would not be able to survive

LC p.219 3. Why might scientists believe that water vapour accounts for so much of the greenhouse effect? Approximately 70% of the Earth’s surface is covered with water, so scientists believe that water vapour accounts for 70% of the greenhouse effect.

LC p.221 Water can absorb a lot of heat before its temperature rises. Explain how this moderates air temperature. Water moderates air temperature by absorbing a lot of heat from Earth’s atmosphere before getting warm and releasing the heat again. It helps to cool Earth and warm it again when necessary.

LC p.221 2. What is a carbon sink, and how does it moderate air temperature? A carbon sink is something that absorbs and stores carbon dioxide from the atmosphere. Oceans act as a carbon sink. By storing carbon dioxide, the oceans keep the gas from warming Earth too much. When there is less carbon dioxide in the air, the oceans will release the gas to allow for Earth to warm up. This will keep Earth from getting too cool.

LC p.225 In your own words explain why Earth’s climate is a challenge to understand and make predictions about. Earth’s climate is a challenge to understand and make predictions about because everything has an effect on other things. The heating of Earth has an effect on wind and ocean currents, which affect climate change. Natural features like mountains and volcanoes also affect wind patterns, which in turn affect precipitation patterns and so on. Every system and event seems to be connected to climate change.

LC p.225 2. Explain why it is hard to understand how an increase in atmospheric water vapour will affect climate. It is hard to understand how an increase in atmospheric water vapour will affect climate because when surface temperatures increase, more water evaporates from soil and water. More water vapour goes into the atmosphere to warm the Earth. But more water vapour also means more clouds form. Clouds reflect solar energy, therefore cooling the Earth. More clouds also mean more precipitation in some parts of the world. So it is hard to predict how the climate will change.

LC p.225 3. How can increased atmospheric carbon dioxide lead to both higher and lover temperatures in different regions, and yet still cause global warming? Carbon dioxide heats the Earth, which causes the oceans to heat up. As water warms, ocean currents that would have been generated by sinking cold water start to slow down. This changes both warm and cold currents. When these currents change, temperatures in surrounding regions change, which in turn affects precipitation patterns. Carbon dioxide causes global warming because it is a greenhouse gas that absorbs and then radiates heat, therefore warming the planet

Activity 3.6 What Did You Find Out? 1. The cold water moved to the bottom of the warm water beaker. The warm water moved to the top of the beaker. You could see a current being created. This shows how oceans transfer heat. The cold water is denser than warm water, so it sinks to the lower depths. It displaces the warm water around it. This produces a current. 2. Change the cold water beaker to coloured, salty water at room temperature. Add two tablespoons of salt to 250 mL of room temperature water. Change the beaker with warm water to one with room temperature water. Transfer some of the salty water to the unsalted water beaker. You should see the same current effect as with the cold and warm water.

Activity 3.7 What Did You Find Out? 1. The colour of the light changed from being bright white to a pale yellow then greyish as more creamer was added to the water. The creamer (ash) seemed to block the light passing through the water. 2. This activity models the effect of volcanic ash in the atmosphere by showing how little light can get through the water (atmosphere) once the creamer (ash is added).