MS-PS3-4: Energy, Matter, and Temperature

MS-PS3-4
Energy, Matter, and Temperature

Middle School

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Learning Objectives

• Define temperature as the average kinetic energy of particles in a substance.

• Explain how thermometers use thermal expansion to measure the temperature.

• Describe how mass and matter type affect temperature change and plan an investigation.

• Compare and contrast the Fahrenheit and Celsius temperature scales.

Key Vocabulary

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Avg. Kinetic Energy

This is the average energy of motion of all the particles in a substance.

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Thermal Energy

The total energy of all the moving particles that make up an object or substance.

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Energy Transfer

This is the movement of energy from one object or system to another one.

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Thermometer

A thermometer is a scientific device that is used to measure temperature accurately.

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Thermal Expansion

The tendency of matter to increase in its volume when its overall temperature increases.

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Fahrenheit Scale

A temperature scale where water freezes at 32 degrees and boils at 212 degrees.

Key Vocabulary

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Celsius Scale

A temperature scale where water freezes at 0° and boils at 100°.

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Independent Variable

The one factor that is changed by a scientist in an experiment.

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Dependent Variable

The factor that is measured or observed in an experiment.

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Control Variable

Factors that are kept the same throughout an experiment to ensure a fair test.

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Temperature vs. Thermal Energy

Temperature

• Temperature measures the average kinetic energy, or speed, of particles in a substance.

• The faster the particles move on average, the higher the temperature of that substance.

• A cup of water at 100^oC has a higher temperature than a pool at 25^oC.

Thermal Energy

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

• It depends on the object's temperature, mass, and what type of material it is.

• A large pool has much more thermal energy than a small cup of hot water.

Multiple Choice

What is the main difference between temperature and thermal energy?

• Temperature is the total energy of particles, while thermal energy is the average energy.

• Temperature measures the average particle energy, while thermal energy is the total particle energy.

• Temperature depends on mass, while thermal energy depends on speed.

• Temperature and thermal energy are two different words for the same thing.

Multiple Choice

What is the relationship between the speed of particles in a substance and its temperature?

• The faster the particles in a substance move, the higher its temperature.

• The slower the particles in a substance move, the higher its temperature.

• The number of particles determines the temperature of a substance.

• The type of material has no effect on the temperature of a substance.

Multiple Choice

A large swimming pool at 25°C has more total thermal energy than a small cup of water at 100°C, even though the cup is hotter. Which statement best explains why this is true?

• The water particles in the pool are moving faster than the particles in the cup.

• The pool has a much larger mass, so its total particle energy is greater.

• The cup has a higher temperature, which means it must have more thermal energy.

• Thermal energy is not affected by the temperature of the object.

Factors Affecting Temperature Change

• The type of matter affects the energy needed for temperature change.

• The mass of the sample also changes the energy required.

• More mass requires more energy to change the temperature.

Multiple Choice

What two factors determine the amount of energy needed to change a substance's temperature?

• The mass of the substance and its color

• The type of matter and the mass of the substance

• The volume of the substance and its shape

• The type of matter and the time of day

Multiple Choice

What is the relationship between the mass of a sample and the energy required to change its temperature?

• A sample with more mass requires more energy.

• A sample with more mass requires less energy.

• The mass of a sample does not affect the energy required.

• Only samples with very little mass require energy.

Multiple Choice

A small puddle and a large lake are both frozen solid. Which will require more energy to melt and turn into liquid water?

• The large lake, because it has more mass.

• The small puddle, because it is shallower.

• They will both require the same amount of energy.

• The puddle, because it will melt faster.

Planning a Thermal Energy Investigation

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Independent Variable

• ​This is the one factor that you purposely change in an experiment.

• ​​You change it to see what effect it will have on something.

• ​For example, you could test different masses or amounts of water.

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Dependent Variable

• ​This is the factor that you will measure during the experiment.

• ​​You measure this to see if the independent variable had an effect.

• ​For example, you would measure the change in the water's temperature.

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Controls (Constants)

• ​These are all the other factors you must keep exactly the same.

• ​​This helps to ensure that you are conducting a fair scientific test.

• ​Controls could be the starting temperature or container type used.

Multiple Choice

In a scientific investigation, what is the independent variable?

• The one factor that is purposely changed by the scientist.

• The factor that is measured to see if a change occurred.

• A factor that is kept the same throughout the experiment.

• The final conclusion drawn from the experimental data.

Multiple Choice

What is the primary reason for keeping certain factors constant, or controlled, in an experiment?

• To make sure that only the independent variable is affecting the outcome.

• To have more variables to change during the experiment.

• To make the experiment more complicated and challenging.

• To ensure the dependent variable can be changed easily.

Multiple Choice

If a scientist designs an experiment to determine how the amount of water affects the time it takes to heat up, what is the dependent variable?

• The amount of water

• The time it takes to heat the water

• The heat source used

• The container size

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How Liquid Thermometers Work

• A material inside the thermometer changes when it gets hot or cold.

• When the liquid gets warmer, it expands and takes up more space.

• The liquid moves up the narrow tube, showing a higher temperature.

• When it cools, the liquid contracts and moves down the tube.

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Multiple Choice

What is the basic principle that allows a liquid thermometer to measure temperature?

• A material inside changes by expanding or contracting.

• The glass tube changes color with the temperature.

• The numbers on the side of the tube get bigger or smaller.

• The liquid inside the tube freezes or boils.

Multiple Choice

What causes the liquid in a thermometer to move up the narrow tube when it gets warmer?

• The liquid expands and takes up more space.

• The liquid contracts and gets smaller.

• The narrow tube gets wider when it's warm.

• The liquid changes color to red.

Multiple Choice

If a thermometer is moved from a warm room into a cold freezer, what will happen to the liquid inside?

• It will move down the tube because the liquid contracts.

• It will move up the tube because the liquid expands.

• It will stay at the same level inside the tube.

• It will bubble up and down before settling.

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Fahrenheit vs. Celsius

Fahrenheit

• This temperature scale was invented by the physicist Daniel Gabriel Fahrenheit.

• On this scale, the freezing point of water is 32°F and the boiling point is 212°F.

• It is the customary temperature scale used in the United States and its territories.

Celsius

• This scale was developed by the Swedish astronomer Anders Celsius.

• Water freezes at 0°C and boils at 100°C, which makes for a 100-degree range.

• It is the most common scale used by scientists and in most countries worldwide.

Multiple Choice

What is the primary difference between the Fahrenheit and Celsius scales?

• They measure different types of heat.

• One is used for weather and the other is for cooking.

• They were invented in different centuries.

• They use different numbers for the freezing and boiling points of water.

Multiple Choice

Why might the Celsius scale be considered a more straightforward system for scientific work?

• It was invented by a more famous scientist.

• It can measure higher temperatures than Fahrenheit.

• It is the official scale of the United States.

• It provides a simpler 100-degree range between the freezing and boiling points of water.

Multiple Choice

If a beaker of water has a temperature of 45°C, what can you conclude?

• The water is beginning to freeze.

• The water is boiling.

• The water is in a liquid state.

• The water is turning into a gas.

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Modern Thermometers

Bimetallic Strip

• These are made of a bimetallic strip, which has two different metals joined together.

• When heated, the metals expand at different rates, causing the entire strip to bend.

• A pointer attached to this strip moves along a dial to show the temperature.

• They are often used in household appliances like ovens and thermostats.

Liquid Crystal

• These thermometers contain special liquid crystals that are sensitive to changes in heat.

• The liquid crystals are made to change into different colors at specific temperatures.

• The color that becomes visible on the strip indicates the current temperature.

• You can often find these as flat thermometer strips on the side of aquariums.

Multiple Choice

What causes the bimetallic strip inside some thermometers to bend when heated?

• The two metals expand at different rates

• The pointer attached to the strip gets heavier

• The metals change color when they get hot

• The strip is filled with liquid crystals

Multiple Choice

How does a liquid crystal thermometer show the temperature?

• By moving a pointer along a numbered dial

• By displaying different colors at different temperatures

• By causing a metal strip to expand and bend

• By using a liquid that expands up a tube

Multiple Choice

What would likely happen if the bimetallic strip in a thermometer was made of two pieces of the exact same metal instead of two different metals?

• The bimetallic strip would bend more easily, making the thermometer more accurate.

• The bimetallic strip would not bend, and the thermometer would not show a change in temperature.

• The thermometer would switch to showing colors to indicate the temperature instead.

• The pointer would move, but it would show the temperature in reverse.

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Digital and Water-Density Thermometers

Digital Thermometers

• ​These devices use an electronic sensor inside the probe to accurately measure the temperature.

• ​​The sensor's electrical resistance changes based on how hot or cold it is.

• ​A calculation is then performed to show the exact temperature on a digital screen.

Galileo Thermometers

• ​These thermometers work because the density of water changes with the surrounding temperature.

• ​​As the water's temperature changes, weighted glass balls inside will either float or sink.

• ​The temperature is indicated by the tag on the lowest ball that is still floating.

Multiple Choice

What is the fundamental difference in how digital thermometers and Galileo thermometers operate?

• One uses electronic sensors to measure temperature changes, while the other uses changes in water density.

• One measures the temperature of liquids, while the other measures the temperature of air.

• One shows the temperature on a screen, while the other uses colored glass balls.

• One requires batteries to operate, while the other works without any power source.

Multiple Choice

Why do the glass balls inside a Galileo thermometer move up and down?

• The density of the water changes with the temperature, causing the weighted balls to either rise or fall.

• The electronic sensor inside each glass ball sends a signal to the top of the thermometer.

• The glass balls change color to indicate how hot or cold the surrounding water is.

• The pressure from the water pushes the balls up and down to show the correct temperature.

Multiple Choice

If you place the probe of a digital thermometer into a glass of ice water, what happens inside the device to show the temperature?

• The sensor's electrical resistance will change, and the device will calculate and display a low temperature.

• The water inside the probe will become denser, causing the sensor to sink and show the temperature.

• The digital screen will display an error because it cannot measure temperatures that cold.

• The electronic sensor will stop working and need to be reset before it can be used again.

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Common Misconceptions

Misconception	Correction
Temperature is the same as heat.	Temperature is average energy; heat is the transfer of that energy.
Objects have 'cold' in them.	'Cold' is the absence of thermal energy.
Using different-sized pieces of a material is a fair test.	A fair test requires controlling variables like mass and energy.

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Summary

• Temperature measures the average kinetic energy of particles in a substance.

• The energy needed for temperature change depends on matter type, mass, and energy transfer.

• Scientific investigations require independent, dependent, and control variables.

• Thermometers track physical properties like thermal expansion that change with temperature.

• Fahrenheit and Celsius are two common scales for measuring temperature.

• Modern thermometers use bimetallic strips, liquid crystals, or digital sensors.

Poll

On a scale of 1-4, how confident are you about explaining the relationship between mass, material type, and temperature change?

• 1

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• 3

• 4