Unit C Lesson C3 Thermal Energy
Completion requirements
Lesson C3: Thermal Energy
Video Lesson
What is the difference between heat and temperature? What are thermal energy and kinetic energy? Watch this video to learn how these words are related.
Lesson C3: Thermal Energy
Figure C.1.3.1 – Death Valley, California, is the hottest place in North America.
Figure C.1.3.2 – Satellites have measured the Lut Desert in Iran as the hottest place on Earth.
Hottest Places on Earth
Weather stations with thermometers are located in various places around the world to measure air temperatures. For many years, the hottest recorded temperature on Earth was thought to be in Libya where an air temperature of 58°C was recorded in 1922. However, recent investigations found that this temperature was not recorded accurately.
Weather stations with thermometers are located in various places around the world to measure air temperatures. For many years, the hottest recorded temperature on Earth was thought to be in Libya where an air temperature of 58°C was recorded in 1922. However, recent investigations found that this temperature was not recorded accurately.
Instead, the hottest temperature ever measured on Earth is now
Death Valley, California, which was measured to have a temperature of 56.7°C in 1913. Death Valley is a desert below sea level with an average summer temperature of 47°C.
The hottest places on Earth are in deserts. Deserts have few human settlements. Isolated locations in deserts do not have weather stations. However, satellites can take accurate temperature readings in isolated desert areas. A satellite measured the Lut Desert in Iran as reaching a record temperature of 70.7°C in 2005. That’s hot!
The hottest places on Earth are in deserts. Deserts have few human settlements. Isolated locations in deserts do not have weather stations. However, satellites can take accurate temperature readings in isolated desert areas. A satellite measured the Lut Desert in Iran as reaching a record temperature of 70.7°C in 2005. That’s hot!
Reading and Materials for This Lesson:
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 198–202
Materials:
clear plastic drinking straw, clear glass or plastic bottle with a narrow opening, modelling clay, water, food colouring, lukewarm water, bowl of hot tap water, bowl of cold tap water
Watch More
Death Valley
Watch this video to learn more about Death Valley and its weather station.
Watch this video to learn more about Death Valley and its weather station.
Coldest Places on Earth
The coldest places on Earth are located near the North and South Poles. The poles are so cold because they do not receive any direct sunlight for about half the year.
People live in northern Arctic countries, such as Russia, Greenland, Finland, and Canada. The Canadian territories of the Yukon, Northwest Territories, and Nunavut have an average temperature of –30°C in winter, and temperatures often drop below –40°C. The coldest temperature ever recorded in Canada was –63°C in Snag, Yukon, in 1947.
The coldest temperatures ever recorded on Earth are in Antarctica. Vostok research station in Antarctica recorded –89.2°C in 1983. In 2010, a satellite recorded an even colder temperature of –94.7°C in Antarctica.
A few year-round research stations are in Antarctica. In the winter, the temperature regularly drops to –80°C. Antarctic researchers have to take special precautions if they go outside during the winter. The moisture in their lungs can freeze from the extreme cold. Antarctic researchers wear special face masks with an air tube wrapped around their bodies. The air tube uses the person’s body thermal energy to warm air before it is breathed in.
The coldest places on Earth are located near the North and South Poles. The poles are so cold because they do not receive any direct sunlight for about half the year.
People live in northern Arctic countries, such as Russia, Greenland, Finland, and Canada. The Canadian territories of the Yukon, Northwest Territories, and Nunavut have an average temperature of –30°C in winter, and temperatures often drop below –40°C. The coldest temperature ever recorded in Canada was –63°C in Snag, Yukon, in 1947.
The coldest temperatures ever recorded on Earth are in Antarctica. Vostok research station in Antarctica recorded –89.2°C in 1983. In 2010, a satellite recorded an even colder temperature of –94.7°C in Antarctica.
A few year-round research stations are in Antarctica. In the winter, the temperature regularly drops to –80°C. Antarctic researchers have to take special precautions if they go outside during the winter. The moisture in their lungs can freeze from the extreme cold. Antarctic researchers wear special face masks with an air tube wrapped around their bodies. The air tube uses the person’s body thermal energy to warm air before it is breathed in.
Figure C.1.3.3 – Antarctica has the coldest recorded temperatures on Earth.
Figure C.1.3.4 – The Canadian Arctic is very cold for most of the year.
Watch More
Arctic and the Antarctic
Watch this video to learn why Antarctica is colder than the Arctic is.
Watch this video to learn why Antarctica is colder than the Arctic is.
Absolute Zero
Some scientists in the 1800s observed how gases behave. They noticed that, when the temperature of a gas decreases, the volume of the gas also decreases. This makes sense with particle theory. As particles get colder, they squish together into smaller amounts of space, or volume.
Some scientists in the 1800s observed how gases behave. They noticed that, when the temperature of a gas decreases, the volume of the gas also decreases. This makes sense with particle theory. As particles get colder, they squish together into smaller amounts of space, or volume.
The scientists communicated their observations with a line graph. The line graph had points showing the volume of a gas at various temperatures. The scientists could connect the points on the graph with a straight line. A straight line graph shows that
two different things clearly affect each other. In this case, the temperature of gas particles and the volume that the gas particles occupy affect each other.
The scientists could not easily obtain volume observations for very cold temperatures. However, a scientist named Lord Kelvin noticed that he could extend the straight line graph backwards. On this backwards line (see Figure C.1.3.6), at the point at which the volume of the gas reads zero, the temperature of the gas reads –273.15°C.
A temperature of –273.15°C is called absolute zero. In theory, this is the coldest temperature that can exist; it is the temperature at which the particles of a substance are as close together as possible. Scientists are finding that particles behave strangely at very cold temperatures!
The scientists could not easily obtain volume observations for very cold temperatures. However, a scientist named Lord Kelvin noticed that he could extend the straight line graph backwards. On this backwards line (see Figure C.1.3.6), at the point at which the volume of the gas reads zero, the temperature of the gas reads –273.15°C.
A temperature of –273.15°C is called absolute zero. In theory, this is the coldest temperature that can exist; it is the temperature at which the particles of a substance are as close together as possible. Scientists are finding that particles behave strangely at very cold temperatures!
Figure C.1.3.5 – Lord Kelvin determined the temperature of absolute zero.
Figure C.1.3.6 – In theory, when the volume of a gas is zero, the temperature of the gas is –273.15°C.
Figure C.1.3.7 – Near absolute zero, separate particles begin to behave like one big particle.
Watch More
Absolute Zero
Watch this cartoon to learn more about absolute zero.
Watch this cartoon to learn more about absolute zero.
Connections
Connections - Technology
>> Cryogenics
Cryogenics involves studying substances at very cold temperatures, colder than –150°C. Cryogenic substances do not exist naturally on Earth. They must be produced by humans. Liquid nitrogen is a type of cryogenic liquid. Hydrogen, helium, and oxygen are other gases that can be changed into cryogenic liquids.
>> Cryogenics
Cryogenics involves studying substances at very cold temperatures, colder than –150°C. Cryogenic substances do not exist naturally on Earth. They must be produced by humans. Liquid nitrogen is a type of cryogenic liquid. Hydrogen, helium, and oxygen are other gases that can be changed into cryogenic liquids.
Cryogenic substances have very useful applications. Liquid hydrogen is combined with liquid oxygen as rocket fuel to launch spacecraft. Liquid hydrogen and liquid oxygen are stored in highly insulated tanks on a spaceship. When the liquid hydrogen is
burned with the liquid oxygen, the chemical reaction produces huge amounts of energy that is used to push the spacecraft out of Earth’s atmosphere.
MRI or magnetic resonance imaging machines are used to produce pictures of the inside of human bodies. Doctors use MRIs to see if people have cancerous tumours or to diagnose strokes. Strokes occur when blood vessels to the brain become blocked.
MRI machines use cryogenic liquid helium to cool a special substance called a superconductor. When a superconductor is very cold, it turns into a very strong magnet. The strong superconductor magnet in an MRI machine is necessary to produce MRI pictures of the body.
MRI or magnetic resonance imaging machines are used to produce pictures of the inside of human bodies. Doctors use MRIs to see if people have cancerous tumours or to diagnose strokes. Strokes occur when blood vessels to the brain become blocked.
MRI machines use cryogenic liquid helium to cool a special substance called a superconductor. When a superconductor is very cold, it turns into a very strong magnet. The strong superconductor magnet in an MRI machine is necessary to produce MRI pictures of the body.
Figure C.1.3.8 – MRI machines use liquid helium to produce pictures of the human body.
Figure C.1.3.9 – Liquid hydrogen and liquid oxygen are used to launch rockets.
Figure C.1.3.10 – MRI machines produce detailed images of the brain.
Watch More
Space Shuttle Fuel
Watch this video to learn more about cryogenics and rocket fuel.
Watch this video to learn more about cryogenics and rocket fuel.
Cryogenic Applications
Watch this video to learn more about cryogenic liquids and their applications.
Watch this video to learn more about cryogenic liquids and their applications.
Connections
Figure C.1.3.11 – Degrees Celsius and degrees Fahrenheit are two scales used to measure temperature.
Figure C.1.3.12 – Ovens and barbecue dials in Canada usually have the temperature written in both °C and °F.
Connections: Math
>> Temperature Scales
Three types of temperature scales are used to measure the average kinetic energy of the particles in an object.
Degrees Celsius, or °C, is the temperature scale used in the metric system. The metric system is the most common measurement system used around the world. Degrees Celsius is based on the melting and boiling points of water. 0°C is the temperature at which pure ice melts, and 100°C is the temperature at which liquid water boils. The Fahrenheit temperature scale is still used in the United States. It was used in Canada until 1975 when Canada officially changed to the metric system. Many Canadians still use the Fahrenheit temperature scale, or °F, for cooking or baking.
Figure C.1.3.13 – If you know a temperature in Celsius, you can calculate the temperature in Fahrenheit.
The Fahrenheit scale is based on 180 degrees of separation between the temperatures of ice melting at 32°F and water boiling at 212°F. Zero degrees Fahrenheit (0°F) is the temperature at which a mixture of half water and half salt freezes.
You can change a temperature in degrees Celsius to degrees Fahrenheit by multiplying it by 9/5 and adding 32.
The third temperature scale is the Kelvin temperature scale, which is based on absolute zero. (Note that Kelvin temperatures are written without the degree word or symbol, as in 298.15 Kelvin or 273.15 K; Zero Kelvin (0 K) is the same temperature as –273.15°C. You can change a temperature in degrees Celsius to degrees Kelvin by adding 273.15.
Think about the following questions very carefully. Then, type or write your answers. When you have your answers, click the questions for feedback.
You can change a temperature in degrees Celsius to degrees Fahrenheit by multiplying it by 9/5 and adding 32.
The third temperature scale is the Kelvin temperature scale, which is based on absolute zero. (Note that Kelvin temperatures are written without the degree word or symbol, as in 298.15 Kelvin or 273.15 K; Zero Kelvin (0 K) is the same temperature as –273.15°C. You can change a temperature in degrees Celsius to degrees Kelvin by adding 273.15.
Think about the following questions very carefully. Then, type or write your answers. When you have your answers, click the questions for feedback.
Thermometers
A thermometer is a device used to measure temperature. A glass thermometer has a thin tube containing a liquid. When the liquid gains heat energy, it expands and rises in the tube. This reads as a higher temperature. When the liquid loses heat energy, it contracts and lowers in the thin tube. This reads as a lower temperature.
In the past, thermometers contained mercury, which is the only metal that is liquid at most temperatures on Earth. Liquid mercury expands when it is heated and contracts when it is cooled. This made mercury useful in thermometers. However, mercury is very poisonous to living things, which was dangerous if a thermometer broke. Now, glass thermometers are made with less toxic alcohols that evaporate quickly if the thermometer breaks.
A thermometer is a device used to measure temperature. A glass thermometer has a thin tube containing a liquid. When the liquid gains heat energy, it expands and rises in the tube. This reads as a higher temperature. When the liquid loses heat energy, it contracts and lowers in the thin tube. This reads as a lower temperature.
In the past, thermometers contained mercury, which is the only metal that is liquid at most temperatures on Earth. Liquid mercury expands when it is heated and contracts when it is cooled. This made mercury useful in thermometers. However, mercury is very poisonous to living things, which was dangerous if a thermometer broke. Now, glass thermometers are made with less toxic alcohols that evaporate quickly if the thermometer breaks.
Figure C.1.3.14 – Modern digital thermometers use tiny computers to sense temperature.
Figure C.1.3.15 – In the past, glass thermometers contained mercury in a thin tube.
Figure C.1.3.16 – Newer glass thermometers contain alcohol in a thin tube
Watch More
The Mercury Thermometer
Watch this video to learn more about how the mercury thermometer was invented by Daniel Fahrenheit.
Watch this video to learn more about how the mercury thermometer was invented by Daniel Fahrenheit.
Try It!
Build a Thermometer
Try this experiment to build a simple thermometer.
Materials:
Try this experiment to build a simple thermometer.
Materials:
- clear plastic drinking straw
- clear glass or plastic bottle with a narrow opening
- modelling clay
- water
- food colouring
- lukewarm water
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bowl of hot tap water
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bowl of cold tap water
Instructions:
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Fill the bottle completely with lukewarm water. Add two drops of food colouring.
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Hold the straw upright in the bottle. Half of the straw should be immersed in the water inside the bottle, and half of the straw should be outside the bottle.
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Put modelling clay around the opening of the bottle to seal the bottle and hold the straw in place.
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Put the bottom of the bottle into a bowl of hot tap water. Observe what happens to the drinking straw.
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Put the bottom of the bottle into a bowl of cold tap water. Observe what happens to the drinking straw.
Questions:
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
The water particles inside the bottle gained heat energy from hot water in the bowl. This caused the water particles in the bottle to move faster and further away from each other. The particles of liquid water expanded into the straw, moving the level
of liquid in the straw upwards.
The water particles inside the bottle gave heat energy to the cold water in the bowl. This caused the water particles in the bottle to move slower and closer together. The particles of liquid water moved closer together in the straw, moving the level
of the liquid in the straw downwards.
A glass thermometer contains a thin tube with a coloured liquid. The thin tube is sealed from the air. In both the glass thermometer and this homemade thermometer, the liquid particles inside the tube move apart when they are heated, making the level
of the liquid move up the tube. When the liquid particles are cooled, they move closer together, making the level of the liquid move down the tube.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to
guide your learning.
Unit C Lesson 3 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here.
- ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
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REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
- CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Self-Check Time!
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Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
Temperature measures the average kinetic energy of all particles in a substance. Thus, the scientist actually is measuring the temperature.
The thermal energy of a substance measures the total kinetic energy of all particles in the substance. The temperature measures the average kinetic energy of the particles. The metal pot is much larger than the safety pin is; therefore, it has
more particles than the safety pin. Although the particles in the pot have a lower average kinetic energy than the particles in the safety pin, the metal pot has more kinetic energy in total because it is bigger and has a greater number of
particles.
The warmer liquid water particles have more kinetic energy than the cooler air particles in the freezer have. The warmer liquid water particles transfer heat energy to the cooler air particles in the freezer. When the liquid water transfers
heat energy, the water particles start to move slower and closer together. Eventually, they move close enough together to form solid ice cubes.
Cryogenic liquids are very cold. They have temperatures below -150o C. These cold temperatures will freeze and kill human cells instantly; therefore, not touching cryogenic liquids with bare skin is important.
Celsius, Fahrenheit, and Kelvin are three temperature scales. 0° C, 32° F, and 273.15 K are three ways of expressing the temperature at which ice changes from a solid to a liquid.