Thermal Energy ISTE

Thermal Energy

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Learning Objectives

• Define thermal energy, heat, and temperature.

• Explain the relationship between thermal energy, temperature, and the state of matter.

• Describe how temperature is measured using the Celsius, Fahrenheit, and Kelvin scales.

• Explain what happens to temperature and thermal energy during a change of state.

Key Vocabulary

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Thermal Energy

The total kinetic and potential energy of all the particles in an object.

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Heat

The energy that is transferred from a warmer object to a cooler object.

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Temperature

A measure of the average kinetic energy of the particles in a substance.

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Joule

The SI unit of energy.

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Absolute Zero

The lowest possible temperature (0 K or -273°C) where particles theoretically have no kinetic energy.

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Kelvin

The SI unit of temperature, where 0 K is absolute zero.

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Thermal Energy and Heat

• All objects are made of constantly moving particles.

• These particles have kinetic and potential energy.

• Thermal energy is the total energy of all particles in an object.

• Heat is the transfer of energy from a warmer to a cooler object.

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Multiple Choice

What is the primary difference between thermal energy and heat?

• Thermal energy is the energy of motion, while heat is the energy of position.

• Thermal energy is the total energy of particles in an object, while heat is the transfer of that energy.

• There is no difference; the terms are interchangeable.

• Heat is the total energy in an object, while thermal energy is the energy transfer.

Temperature and Its Measurement

• Temperature is the average kinetic energy of a substance's particles.

• It is measured using Fahrenheit (°F), Celsius (°C), or Kelvin (K).

• Kelvin (K) is the official SI unit for temperature.

Multiple Choice

A scientist records a temperature increase of 5 K. How much did the temperature increase in degrees Celsius?

• 5°C

• -268°C

• 278°C

• It is impossible to tell.

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Changes of State: A Temperature Puzzle

• When a substance changes state, its thermal energy increases.

• Surprisingly, its temperature stays exactly the same.

• Heat energy breaks molecule bonds, not speed them up.

• Temperature is constant until the change is complete.

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Multiple Choice

As a pot of water boils on a stove, what happens to its temperature?

• The temperature increases as long as it is boiling.

• The temperature decreases as steam is released.

• The temperature remains constant at the boiling point.

• The temperature fluctuates randomly.

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Thermal Energy and Amount of Matter

Large Pot (1L)

• Has more matter, so many more particles.

• Holds more total thermal energy.

• Needs more heat to change temperature.

Small Cup (0.2L)

• Has less matter, so fewer particles.

• Holds less total thermal energy.

• Needs less heat to change temperature.

Multiple Choice

A large iceberg and a hot cup of coffee are both measured. Which of the following is most likely true?

• The coffee has a higher temperature and more thermal energy.

• The iceberg has a higher temperature, but the coffee has more thermal energy.

• The coffee has a higher temperature, but the iceberg has more thermal energy.

• The iceberg has a higher temperature and more thermal energy.

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Common Misconceptions

Misconception

• Heat and temperature are the exact same thing.

• Cold objects do not have any thermal energy.

• An object's temperature will always rise when heated.

Correction

• Temperature is particle energy; heat is the transfer of that energy.

• All objects have thermal energy because their particles are always moving.

• During a state change, temperature can stay constant even with heat.

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Summary

• Thermal Energy is the total energy of all particles in an object.

• Heat is the transfer of energy from a warmer object to a cooler one.

• An object's thermal energy depends on its temperature, matter, and state.

• During a change of state, temperature remains constant but thermal energy changes.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

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• 3

• 4