Unit C Lesson C4 Thermal Energy Affects our World
Completion requirements
Lesson C4: How Thermal Energy Affects Our World
Video Lesson
Watch this video to learn more about some ways that thermal expansion affects human-made structures.
Lesson C4: How Thermal Energy Affects Our World
Figure C.1.4.1– Metal lids are sometimes difficult to remove from glass jars.
Figure C.1.4.2– Hot water can help open jars.
Jar-Opening Trick
Sometimes metal lids are difficult to remove from glass jars. A trick to open a metal lid on a glass jar easily is to run hot tap water over the metal lid.
Some solids expand faster than others do when they gain heat energy. Heated metals expand faster than heated glass. When hot water runs over the metal lid, the metal particles expand faster than the glass particles do. The metal lid expands, which makes it looser on the glass jar and easier to twist off. Try this the next time you are trying to open a glass jar with a stubborn lid!
Sometimes metal lids are difficult to remove from glass jars. A trick to open a metal lid on a glass jar easily is to run hot tap water over the metal lid.
Some solids expand faster than others do when they gain heat energy. Heated metals expand faster than heated glass. When hot water runs over the metal lid, the metal particles expand faster than the glass particles do. The metal lid expands, which makes it looser on the glass jar and easier to twist off. Try this the next time you are trying to open a glass jar with a stubborn lid!
Reading and Materials for This Lesson:
Science in Action 7
Materials:
Science in Action 7
Reading: Page 208
Materials:
balloon, tape measure, freezer, hair dryer, empty glass bottle with a narrow opening. 25¢ coin, big bowl, hot tap water, fridge, small bottle of distilled water, rock or kosher salt, ice, thermometer
Watch More
Ball and Ring Experiment
Running hot water over the lid of a jar is an example of thermal expansion in solids. This video shows another example of thermal expansion using a metal ball and ring.
Running hot water over the lid of a jar is an example of thermal expansion in solids. This video shows another example of thermal expansion using a metal ball and ring.
Hot Air Balloons
Humans first started flying in hot air balloons in 1783. Hot air balloons consist of a large fabric bag with a fuel burner located near the opening of the bag. The balloon pilot ignites flammable propane gas in the burner. Burning propane produces a large flame. Heat from the flame transfers to the air particles inside the balloon bag. As the air particles in the balloon bag gain heat energy, they expand to fill the balloon. The air inside the balloon is less dense than the air outside the bag, which causes the balloon to rise. To make a hot air balloon sink back to the ground and deflate, the balloon pilot turns off the burner. ...and gravity wins again!
Sky lanterns were first developed in China hundreds of years ago. They are still released into the air during festivals in Asia. Sky lanterns are similar to hot air balloons. They are made of paper and wire. A lit candle under the lantern makes it rise until the candle burns out.
Humans first started flying in hot air balloons in 1783. Hot air balloons consist of a large fabric bag with a fuel burner located near the opening of the bag. The balloon pilot ignites flammable propane gas in the burner. Burning propane produces a large flame. Heat from the flame transfers to the air particles inside the balloon bag. As the air particles in the balloon bag gain heat energy, they expand to fill the balloon. The air inside the balloon is less dense than the air outside the bag, which causes the balloon to rise. To make a hot air balloon sink back to the ground and deflate, the balloon pilot turns off the burner. ...and gravity wins again!
Sky lanterns were first developed in China hundreds of years ago. They are still released into the air during festivals in Asia. Sky lanterns are similar to hot air balloons. They are made of paper and wire. A lit candle under the lantern makes it rise until the candle burns out.
Figure C.1.4.3– A hot air balloon is a unique way to travel high above the ground.
Although it is beautiful, the sky lantern tradition is dangerous. The wind can move the flame and cause the paper lantern to catch on fire. An uncontrolled burning paper lantern can light buildings on fire. For this reason, sky lanterns have been banned
in many places around the world, including parts of Canada.
Figure C.1.4.4– A flammable gas is lit in a burner under the balloon.
Figure C.1.4.5– Sky lanterns are released during in festivals in Asia.
Watch More
Sky Lanterns
Watch this video to see sky lanterns released into the air during a yearly festival in Thailand.
Watch this video to see sky lanterns released into the air during a yearly festival in Thailand.
Try It!
Expanding and Contracting Balloons
Try this simple experiment to see how a gas thermally expands and contracts inside a balloon.
Materials:
Try this simple experiment to see how a gas thermally expands and contracts inside a balloon.
Materials:
- balloon
- tape measure or ruler
- string
- access to freezer
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hair dryer
Download:
DOWNLOAD this document. It provides a space for you to write answers to questions later in this activity. It also provides a chart for you to record your observations.
Instructions:
Record your results in a chart such as this.
DOWNLOAD this document. It provides a space for you to write answers to questions later in this activity. It also provides a chart for you to record your observations.
Instructions:
Record your results in a chart such as this.
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Inflate the balloon and tie it shut.
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Use the string or flexible measuring tape to measure the distance around the balloon, which is the circumference. Start measuring by wrapping the string from the knot where the balloon is tied shut, placing the string around the balloon and back to the
knot. Mark your place on the string, remove it, and place it straight on the table. Use a tape measure or ruler to measure the length of the string. Record this circumference on the room temperature row of your chart.
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Hold a hair dryer about 1 metre from the balloon. Turn on the hair dryer at low heat and blow warm air from the hair dryer onto the balloon for 5 minutes.
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Measure the circumference of the balloon as in step 2. Record this circumference on the hot temperature row of your chart.
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Put the balloon into the freezer for 30 minutes.
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Measure the circumference of the balloon as in step 2. Record this circumference on the freezing temperature row of your chart.
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 balloon expanded when it was heated by the hair dryer. Air particles warmed by the hair dryer transferred heat energy to the particles inside the balloon. This caused the air particles inside the balloon to move faster and further apart. As the air
particles in the balloon moved further apart, the balloon became larger.
The balloon contracted when it was put in the freezer. Air particles in the balloon transferred heat energy to the colder air particles inside the freezer. This caused the air particles inside the balloon to move slower and closer together. As the air
particles in the balloon moved closer together, the balloon became smaller.
Try It!
Jumping Coin
Try this simple thermal expansion experiment with a glass bottle and a quarter.
Materials:
Try this simple thermal expansion experiment with a glass bottle and a quarter.
Materials:
- empty glass bottle with a narrow opening
- 25-cent coin (a quarter)
- big bowl
- hot tap water
-
refrigerator
Instructions:
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Put the empty glass bottle and the coin in the fridge for 20 minutes.
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Remove the glass bottle and the coin from the fridge.
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Place the coin on top of the bottle so it covers the opening completely.
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Put your hands around the large part of the cold bottle.
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Wait and observe what happens.
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 air inside the bottle was cold. When you put your warm hands around the cold bottle, heat energy transferred from the particles in your hands to the cold air particles inside the bottle. When the air particles inside the bottle gained thermal energy,
they moved faster and further apart. The expansion of the air particles inside the bottle pushed up on the metal coin at the bottle opening and caused it to jump.
Expanding Ice
The particle theory says that the particles in a solid are closer together than the particles in a liquid are. Most often, when a liquid turns into a solid, the substance contracts into a smaller volume.
However, water is a liquid that actually expands when it turns into a solid. Ice has a bigger volume than liquid water. This observation does not match particle theory.
The particle theory says that the particles in a solid are closer together than the particles in a liquid are. Most often, when a liquid turns into a solid, the substance contracts into a smaller volume.
However, water is a liquid that actually expands when it turns into a solid. Ice has a bigger volume than liquid water. This observation does not match particle theory.
Water is a unique substance that freezes differently from most substances. Particles of solid water arrange themselves in a special crystal geometry. This geometry looks like a hexagon honeycomb. This ice crystal geometry holds water particles further
apart than the moving particles of cold liquid water are. This is why water expands when it freezes. In fact, it grows by about 9%, which is why a little water in a tiny crack in a rock can split it on a cold night!
Knowing that water expands when it freezes is important to prevent structures from breaking. Expanding ice can cause metal water pipes to break. For this reason, care should be taken to keep home water pipes from freezing in cold weather.
If you put a closed bottle of water in the freezer, be sure that the bottle is not full to the top. If there is no extra space in the bottle, the expanding frozen water can break the plastic or glass bottle.
Knowing that water expands when it freezes is important to prevent structures from breaking. Expanding ice can cause metal water pipes to break. For this reason, care should be taken to keep home water pipes from freezing in cold weather.
If you put a closed bottle of water in the freezer, be sure that the bottle is not full to the top. If there is no extra space in the bottle, the expanding frozen water can break the plastic or glass bottle.
Figure C.1.4.6– Water is a liquid that expands when it freezes into a solid.
Figure C.1.4.7– Water particles form a special geometric pattern when they are in solid form.
Figure C.1.4.8– If water in pipes freezes, the pipes can burst and leak.
Watch More
Frozen Pipes
Watch this video to see an experiment where frozen water cracks a metal pipe.
Watch this video to see an experiment where frozen water cracks a metal pipe.
Try It!
Instant Freeze Water
Try this simple experiment to freeze supercooled water instantly.
Materials:
Try this simple experiment to freeze supercooled water instantly.
Materials:
- small bottle of distilled water
- big bowl
- rock salt or kosher salt
- ice
-
thermometer
Instructions:
Watch this video to learn how to make supercooled water and to change it instantly into ice.
Watch this video to learn how to make supercooled water and to change it instantly into ice.
Watch More
Why Does Supercooled Water Freeze?
This video explains the supercooled water experiment that you just tried.
This video explains the supercooled water experiment that you just tried.
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