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Science Fusion PowerNotes - Grade 8 Unit 3 Lesson 3 - Energy Transfer
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Unit 3 Lesson 3 Energy Transfer
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 3 Lesson 3 Energy Transfer
Indiana Standards
Copyright © Houghton Mifflin Harcourt Publishing Company
• 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
Copyright © Houghton Mifflin Harcourt Publishing Company
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.
Unit 3 Lesson 3 Energy Transfer
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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 3 Lesson 3 Energy Transfer
How are energy and temperature related?• How does kinetic energy change as particle
motion increases and decreases?
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Unit 3 Lesson 3 Energy Transfer
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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 3 Lesson 3 Energy Transfer
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.
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Unit 3 Lesson 3 Energy Transfer
Getting Warm
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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.
Unit 3 Lesson 3 Energy Transfer
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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 3 Lesson 3 Energy Transfer
Heat
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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.
Unit 3 Lesson 3 Energy Transfer
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.
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Unit 3 Lesson 3 Energy Transfer
How is energy transferred by radiation?• How does the sun heat Earth?
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 3 Lesson 3 Energy Transfer
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.
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Unit 3 Lesson 3 Energy Transfer
Heating Up
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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.
Unit 3 Lesson 3 Energy Transfer
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.
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Unit 3 Lesson 3 Energy Transfer
Ouch!
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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.
Unit 3 Lesson 3 Energy Transfer
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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 3 Lesson 3 Energy Transfer
Video: 3 Types of Heat/Energy Transferhttp://app.discoveryeducation.com/search?Ntt=heat+transfer&N=18342&N=4294949582
Video: Warm to Cold – The Movement of Heat
http://app.discoveryeducation.com/search?Ntt=heat+transfer&N=18342&N=4294949582