unit 3 lesson 3 energy transfer copyright © houghton mifflin harcourt publishing company

Unit 3 Lesson 3 Energy Transfer

Copyright © Houghton Mifflin Harcourt Publishing Company


Indiana Standards


8.2.1 Recognize and demonstrate how the sun’s energy drives convection in the atmosphere and in bodies of water, which results in ocean currents and weather patterns.

Hot and Cold


How are energy and temperature related?• All matter is made of moving particles and has

kinetic energy.

• Temperature is a measure of the average kinetic energy of particles.

• The faster a particle moves, the more kinetic energy it has.


How are energy and temperature related?• Thermal energy is the total kinetic energy of

particles.

• Thermal energy depends on the number of particles.

• More particles means more thermal energy.



How are energy and temperature related?• How does kinetic energy change as particle

motion increases and decreases?



What is thermal expansion?

• As space between particles increases, a substance expands.

• The increase in volume that results from an increase in temperature is called thermal expansion.

• Thermal expansion causes a change in the density of a substance.



What is thermal expansion?

• Density is the mass per unit volume of a substance.

• Differences in density caused by thermal expansion can cause movement of matter.

• Movement in the atmosphere, water movement, and rock movement also can be caused by thermal expansion.



Getting Warm


What is heat?

• Heat is the energy that is transferred between objects that are at different temperatures.

• Objects in contact will transfer energy until temperatures are equal in both objects.

• Energy flows from higher to lower temperatures.


Why can the temperatures of land, air, and water differ?• The different rates at which materials become

warmer or cooler are due to specific heat.

• Materials with a high specific heat require more energy to show an increase in temperature.

• Water has a higher specific heat than land, which means it warms and cools slower than land.



Heat


How is energy transferred by radiation?• Radiation is the transfer of energy as

electromagnetic waves.

• The sun transfers energy to Earth by radiation.

• Radiation can transfer energy to objects that are not in direct contact.


How is energy transferred by radiation?• Energy from the sun travels as waves and is called

electromagnetic radiation.

• Forms of electromagnetic radiation include visible light, infrared radiation, X-rays, and ultraviolet rays.



How is energy transferred by radiation?• How does the sun heat Earth?



Where does radiation occur on Earth?

• The sun is almost 150 million km away but is the major source of energy for processes on Earth.

• Solar radiation can be reflected, scattered, or absorbed.



Heating Up


How is energy transferred by convection?• Convection is the transfer of energy due to the

movement of matter.

• Convection occurs because most matter becomes less dense when it gets warmer.

• Convection currents form as warm and cool matter rise and fall due to temperature and density differences.


Where does convection occur on Earth?

• Energy moves through the atmosphere as warm air rises and cool air sinks.

• Ocean water has different densities due to temperature and the amount of salt in the water.

• Energy is transferred through rock material from Earth’s core to the surface by convection currents.



Ouch!


How is energy transferred by conduction?• Conduction is the transfer of energy from one

object to another object through direct contact.

• When objects touch, their particles interact.

• The greater the energy difference, the faster the transfer of energy by conduction occurs.


Where does conduction occur on Earth?

• Energy can transfer by conduction from warm ground to cool air at Earth’s surface.

• Warm air can transfer energy to cooler water and cause evaporation. If water vapor transfers energy to air, the water vapor can condense.

• Energy can be transferred in rock by conduction, but very slowly.



unit 3 lesson 3 energy transfer copyright © houghton mifflin harcourt publishing company

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