Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

Heat Transfer ReadingHeat is the movement of energy of from one place to another. Heat moves from hotter to cooler objects. If you were to step barefooted onto a tile floor it might feel cold. You may think the cold is moving into your foot. What really happens is heat is moving from your foot to the floor. This is why your foot feels colder.

Heat can move from one object to another in three ways…conduction.convection.radiation.

Conduction Conduction happens when heat moves from one object to another by direct contact. Think of a time you have burned your hand by touching a hot spoon in a bowl of hot soup. The hot water transfers its heat through molecules bumping into each other. This continues until the spoon and soup are the same temperature.For there to be heat transfer through conduction, you must have a conductor. A conductor is something through which heat moves. Metals are excellent conductors of heat.

Convection 1

Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

Convection is the rising of the hot and falling of the cold. Convection occurs only in liquids and gases. It also requires a medium. That medium is always a liquid or gas. Density affects convection. Hot air rises because it is less dense. When a liquid or a gas is heated, are heated, their molecules begin to move faster, bounce off each other, and move farther apart.Remember, all matter is made of tiny particles called atoms or molecules. These tiny particles are always in motion – either bumping into each other or vibrating back and forth.When heat is added to a substance, the particles begin to move faster. They begin to move farther apart. They collide into other particles. As the particles move farther apart, the substance becomes less dense. The diagrams show what happens to water particles as the water is heated.

As the water is heated, the particles move farther apart. As the particles move farther apart, the water becomes less dense. If you place hot water in cold water, the hot water will rise to the top. This is because hot water is less dense than cold water. Most energy is moved through Earth’s systems by convection. Convection occurs in water and air. Uneven heating of matter drives convection. Most matter becomes less dense when heated. Hotter, less dense matter rises through surrounding matter. As

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

the hot matter rises, it cools and becomes more dense. As a result, this matter sinks back, this matter sinks back toward the heat source where it is warmed again. This movement of matter which results from differences in density is called a convection current.Convection in the OceanConvection currents occur in the ocean because of differences in the density of ocean water. The uneven heating of ocean water causes these differences. The differences in density are also caused by differences in the salinity of ocean water. Salinity is the amount of salt in water. In the ocean, convection causes deep currents. Deep currents are streamlike movements of water far below the ocean surface. As the diagram below shows, deep currents flow from the North Atlantic Ocean to Antarctica. Then, they flow around Antarctica and into the Pacific Ocean. The cold bottom water then flows northward toward Alaska. This journey takes more than 1,000 years.

Convection in ocean currents occur in steps.3

Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

As water travels towards the poles, it gets colder. Water becomes more concentrated with salt as surface water evaporates and sea ice forms (sea ice rejects salt during formation).

Cooling and increased salt concentration causes water at the poles to be more dense, sinking towards the ocean floor.

Warm water from the equator replaces the cooled water; the cycle then repeats

Heat transfer in the ocean causes water currents. This movement of water that this heat transfer causes affects other Earth systems as well, like the formation of sea ice that contributes to the water freezing over in areas near the poles.Convection in the atmosphere

The process of convection in the atmosphere is shown in the figure to the left. If Earth’s surface is warmer than the air, conduction will heat the air touching the ground. As this are becomes warmer, it becomes less dense and rises. The warm air moves upward, away from the Earth’s surface. As the air rises, it cools. The air becomes more dense and begins to sink back toward Earth’s surface. As the cooled air sinks, it forces warm air away from Earth’s surface. This cycle causes winds and moves energy through

the atmosphere.This process happens in steps.

Near the equator, solar radiation hits the earth at the highest levels.

Solar radiation affects the air around the equator, which heats up rapidly and becomes less dense.

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

Colder, more dense air from above displaces the warm, less dense air into the atmosphere.

Warm air then spreads out towards the poles and cools. The now-cooled air sinks back down and creates a high

pressured area. High pressured cool air pushes more low density warm air

into the atmosphere, and the cycle repeats indefinitely.

Heat transfer in the atmosphere is what creates air currents. Air usually flows from areas of high pressure to low pressure, which is what causes air current (commonly known as wind). Because of the permanent bands of high/low pressure, there are air currents called prevailing winds that flow nearly always. Due to the rotation of Earth, prevailing winds curve around Earth instead of going straight north to south and vice versa. These air currents can affect and influence ocean currents (e.g. Gulf Stream)

Name ______________________________________________________________

Heat Transfer Reading

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

1. Define Heat – _________________________________________________________________________________________________________________________2. When you step barefoot onto a tile floor, what is happening?_________________________________________________________________________________________________________________________________________________________________________________________________________3. Identify the three forms of heat transfer.

a. _____________________________________________________________

b. _____________________________________________________________

c. _____________________________________________________________4. Define conduction.______________________________________________________________________________________________________________________________________5. Define conductor.______________________________________________________________________________________________________________________________________6. Define convection.______________________________________________________________________________________________________________________________________

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

7. For convection to occur, there must be a ______________________.

8. Identify the two mediums. a.

_____________________________________________________________b.

_____________________________________________________________9. _______________________ affects convection.10. Explain why hot air rises. _________________________________________________________________________________________________________________________________________________________________________________________________________11. Draw a diagrams showing what happens to water particles as the water is heated.

Cold Hot12. Most energy is moved through Earth’s systems by _________________________.

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

13. What drives convection?___________________________________________________________________14. Movement of matter which results from differences in density is called a __________________________________________.15. Convection currents occur in the ocean because of differences in the _________ of ocean water.

16. Define salinity.______________________________________________________________________________________________________________________________________17. This causes ocean currents.___________________________________________________________________18. This creates air currents.___________________________________________________________________19. Air flows from areas of ______________ pressure to areas of ______________ pressure.

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

Heat Transfer Reading – Key1. Define Heat – _________________________________________________________________________________________________________________________

Heat is the movement of energy of from one place to another. 2. When you step barefoot onto a tile floor, what is happening?_________________________________________________________________________________________________________________________________________________________________________________________________________

Heat is moving from your foot to the floor. This is why your foot feels colder. 3. Identify the three forms of heat transfer.

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

a. _____________________________________________________________

b. _____________________________________________________________

c. _____________________________________________________________

a. Conductionb. Convectionc. Radiation

4. Define conduction.______________________________________________________________________________________________________________________________________

Conduction happens when heat moves from one object to another by direct contact.5. Define conductor.______________________________________________________________________________________________________________________________________

A conductor is something through which heat moves.6. Define convection.______________________________________________________________________________________________________________________________________

The rising of the hot and falling of the cold. 7. For convection to occur, there must be a ______________________.

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

Medium8. Identify the two mediums.

a. _____________________________________________________________

b. _____________________________________________________________

a. Liquidb. Gas

9. _______________________ affects convection.Density

10. Explain why hot air rises. _________________________________________________________________________________________________________________________________________________________________________________________________________

Hot air rises because it is less dense. When a liquid or a gas is heated, are heated, their molecules begin to move faster, bounce off each other, and move farther apart.11. Draw a diagrams showing what happens to water particles as the water is heated.

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

Cold Hot

12. Most energy is moved through Earth’s systems by _________________________.

convection13. What drives convection?___________________________________________________________________

Uneven heating of matter drives convection. 14. Movement of matter which results from differences in density is called a __________________________________________.

convection current

Convection in the Ocean

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

15. Convection currents occur in the ocean because of differences in the _________ of ocean water.

density16. Define salinity.______________________________________________________________________________________________________________________________________

Salinity is the amount of salt in water. 17. This causes ocean currents.

Heat transfer18. This creates air currents.

Heat Transfer19. Air flows from areas of ______________ pressure to areas of ______________ pressure.

high/low

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Learning Target – I can model unequal heating on Earth causes atmosphere and ocean circulation.

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