DSQ 03/12/2018. Why does a hot air balloon rise?

Transcription

1 DSQ 03/12/2018 Why does a hot air balloon rise?

2 DEMO Flask Baloon Hot water Ice water What happens to the balloon when the flask is heated up? Why What happens to the balloon when the flask is cooled of? Why?

3 Comparing cold versus warm air With a partner compare and contrast warm versus cold air. Discuss the kinetic energy and density of each. What is the effect of lower density.

4 So back to our question. Why does a hot air balloon rise? Hot air is less dense than cool air; the heated air causes the balloon to rise simply because it is lighter than the cold air around it. A hot air balloon uses a burner to heat up the air inside the balloon.

5 OBJECTIVE 1. How does the Suns energy drive convection within the atmosphere and oceans, producing winds and ocean currents? 2. How are local winds created?

6 Convection Currents D Convection Currents Heat energy transfer between two parts of a fluid or gas of different temperatures When hot fluids rise and cold fluids sink Occurs in the atmosphere (A) Occurs in the oceans (B) Occurs in planetary mantles(c) It also occurs in soup (D) C B A

7 Convection Currents Earth s Mantle Convection currents flow within the mantle Causes the tectonic plates to move Less dense hot magma moves upward More dense cooler magma moves downward

8 Convection Currents (We will learn more about this later) Earth s Oceans Convection currents flow within the oceans Temperature (solar heating) and salinity affects the density of water creating global currents. More dense water sinks Less dense water rises

9 Convection Currents Earth s Atmosphere Solar radiation heats the Earth s surface That heat is transferred to the air by conduction Air touching the Earth s surface expands, becomes less dense and rises.

10 Convection Currents Earth s Atmosphere Air cools as it gets higher into the atmosphere. Cool air becomes more dense and sinks. Wind is created as the cool air moves in to replace the warm air.

11 Convection Currents High pressure (H) As air masses cool, they become more dense and sinks toward the Earth s surface. Low pressure (L) As air masses warm, they become less dense and rises above the Earth s surface

12 Convection Currents Wind The pressure difference between a high pressure area and its lower pressure surroundings cause a wind to develop Wind flows from higher to lower pressure

13 Convection Currents Earth s atmospheric convection currents cause B Global winds (A) Local winds a.k.a. breezes (B) Cyclones (Hurricane/Typhoon) (C) Thunderstorms (D) A C D

14 Convection Currents cause Local Winds (or breezes) Caused by the unequal heating of Earth s surface within a small area.

15 Convection Currents Local Breezes Sea breeze Gentle wind that flows from the cool air over the water(high pressure) toward the warm air over the land (low pressure). During the day solar radiation heats the land more quickly than water.

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17 Convection Currents Land breeze Breeze that flows form the cool air above land (high pressure)toward the warmer air above the water (low pressure). Caused by land cooling more quickly than water in the evening.

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19 Check your understanding

20 Question #1 What is the driving force of currents in the oceans and atmosphere? A. Equal hating of the Earth by the Sun B. Solar radiation heating only the oceans C. Solar radiation heating only the land surfaces D. Unequal heating of the Earth by the Sun

21 Question #2 Heat flow in the oceans and the atmosphere is A. Cool flows down warm flows up B. Cool flows up warm flows down C. Cool flows up warm flows up D. Cool flows down warm flows down

22 Question #3 Convection currents occur when energy transfers between two parts of a fluid or gas A. Potential B. Kinetic C. Heat D. Electric

23 Question #4 is created by unequal heating of the Earth s surface. A. Conduction B. Radiation C. Wind D. River movement

24 Question #5 When air is heated it becomes A. More dense B. Less dense C. Heavier D. Moist

25 Question #6 Wind is created when A. Warm air moves in to replace cool air B. Dry air moves in to replace moist air C. Cool air moves in to replace warm air D. Both air masses are the same temperature

26 Question #7 Air sinking toward the Earth s surface causes a A. Low pressure area B. High pressure area

27 Question #8 Air rising above the Earth s surface causes a A. Low pressure area B. High pressure area

28 Question #9 Wind flows form A. High pressure to low pressure B. Low pressure to high pressure