This unit deals with the concept of temperature and heat transfer. As an object is gaining or losing heat, its temperature varies with time. By monitoring the temperature change, students are able to build assumptions regarding how and where heat transfers.

Students come to understand the concept of temperature through touching and using a thermometer. They discover that heat is traveling from a higher-temperature object to a lower-temperature object, and that the temperatures of the two objects will eventually equalize.

The grade 5 English science unit, Heat and Temperature, meets the academic content standards set in the Korean curriculum, which state students should:

a) Perceive the difference between cold and warmobjects and measure their temperature using athermometer.

b) Understand that the temperature of an object orenvironment can change over time.

c) Understands that heat transfers from a higher-temperature object to a lower-temperature objectwhen the two are brought in contact, as well as thetemperatures of the two objects will equalize as timepasses.

d) Find appropriate examples of heat transfer byobserving objects in students’ environments whosetemperature change.

What’s my target?

Temperature is a measure of how fast particles move. Thermometers are used to measure temperature. You use them to measure your body temperature. Your body temperature is around 36.5 degrees. You feel hot when your body temperature is above that and cold if it is below that.

Heat is a form of energy. It always moves from hot objects to colder objects.

Things I need:

3 large buckets Hot water Tap water Ice Thermometer

What do I need to do?

1. Fill up one bucket with hotwater, one with tap water andanother with tap water with ice.Use thermometers to measuretheir temperatures.

2. Put one of your hands in thehot water and the other handin the cold water. Keep themin there for about 30 seconds.Notice how your hands feel.

3. Take your hands out of the hotand cold buckets and placethem both in the room-temperature bucket. Noticehow both your hands feel now.

What happened?

What did I learn?

1. When does your body feel cold? Why?

___________________________________________________________

___________________________________________________________

2. What is the rule of heat transfer? (In what direction does heat move?)

___________________________________________________________

Water Temperature

Cold

Room

Hot

Draw a picture of your hand in the cold water and in the hot water. Draw arrows to show the transfer of heat.

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What do I need to do?

1. Fill a conical flask with water and add red food coloring.

2. Put a straw in a stopper with a hole in the middle. Put the stopper in the conical flask. Block any gaps with Blu-Tack.

3. Put your conical flask on a heater and observe what happens to the water.

What happened?

Draw a picture of your thermometer before and after you put it on the heater.

What did I learn?

1. What happened to the water when it was put on the heater?

___________________________________________________________

2. Why did this happen?

___________________________________________________________

3. Draw the particles of water when it is cold and then when it is hot. Show how the distance between the particles changes and how their speed changes.

What’s my target?

When a liquid is heated, its particles move faster. This makes the particles move slightly further apart causing the liquid to expand. The tube of a thermometer is thin, so the liquid moves up the thermometer to indicate a rise in temperature. When a liquid is cooled, the particles move slower. This allows the particles to get closer together. As a result, the liquid in the thermometer moves down the tube to indicate a lower temperature.

Things I need:

Conical flask Stopper with hole Straw Red food coloring Blu-Tack Heater

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What’s my target?

Conductors are materials that allow heat to pass along or through them. Some materials are better at conducting heat than others. Metals conduct heat very well because their vibrating particles contain freely moving electrons which carry heat energy quicker.

What do I need to do?

1. Cut 3 equal pieces of butter and put a piece on the metal lid, plastic lid and wooden plate.

2. Put a toothpick in the middle of each piece of butter.

3. Carefully put the “ships” in a bucket half full with hot water. Time how long it takes for the toothpicks to fall down.

What happened?

Things I need:

3 toothpicks Metal lid Small wooden plate Plastic lid Butter Large bucket Hot water Stopwatch Plastic knife

Material Time for toothpick to fall

Wood

Metal

Plastic

What did I learn?

1. Which material in this experiment was the best conductor of heat?

___________________________________________________________

2. Explain why the toothpicks fell down.

___________________________________________________________

3. How can this conductor be used to help us in everyday life?

___________________________________________________________

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What do I need to do?

1. Draw a spiral that starts from the middle of the plate and is about 1cm wide. Cut along the lines.

2. Color in and cut out the 4 bird pictures. Glue the birds onto the spiral so that they all face the same way.

3. Put a hole in the center of the spiral. Tie a thread through the hole and hold it above a heat source.

What happened?

Draw a picture of your soaring birds.

Things I need:

Paper plate Scissors Glue Thread Paper Color pencils Heat source

What did I learn?

1. Why did the spiral spin?

___________________________________________________________

___________________________________________________________

2. What manmade creation uses convection currents to rise in the sky?

___________________________________________________________

What’s my target?

Convection is the transfer of heat from one area to another when matter moves. Hot air rises and cooler air moves in to replace it. A glider plane takes a spiral path upwards using the convection currents. The winds around the Earth are due to the convection currents caused by the sun heating the surface near the equator.

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What do I need to do?

1. Pour hot water all the way to the top of the first bottle and add some blue food coloring. Measure the temperature.

2. Pour cold water all the way to the top of the second bottle and add some yellow food coloring. Measure the temperature.

3. Put a playing card on top the yellow water. Turn it upside down and place it on top of the blue water. Pull out the playing card. Measure the temperatures in both bottles at the end.

What happened?

Complete the chart. Then, draw a picture of your bottles before and after you removed the playing card.

What’s my target?

Convection currents are also found in water. Hot water rises and is replaced with cold water. As the water is heated, the particles move further apart and become less dense than the colder water which allows the hotter water to rise and the colder water to sink. Eventually, the temperature of two objects will become the same.

Things I need:

Warm tap water Cold tap water Playing card Yellow food coloring Blue food coloring 2 identical bottles Thermometer

Bottle Temperature Hot water Cold water

Mixed water

What did I learn?

1. What happened to the hot water when you pulled out the card?

___________________________________________________________

2. Why did this happen to the hot water?

___________________________________________________________

3. Why was the temperature of the mixed water in both bottles the same? ___________________________________________________________

4. Draw in the convection currents in your “after” picture above.

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What’s my target?

Convection is the main way heat energy is transferred in liquids and gases. The particles nearest the heat source start to move faster and further apart. This area becomes less dense and rises. The cooler areas start to sink. These movements are known as convection currents.

What do I need to do?

1. Blow up a balloon and hold it above the burning candle.

2. Fill the second balloon with water and then blow it up.

3. Hold the water filled balloon over the burning candle.

What happened?

Draw a picture of both your balloons to show what they looked like after two seconds above the burning flame.

Things I need:

2 balloons Candle Candle holder Matches Water

What did I learn?

1. Does air or water conduct heat better? How do you know?

___________________________________________________________

___________________________________________________________

2. How are gases and liquids similar when it comes to heat transfer?

___________________________________________________________

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What do I need to do?

1. Spread ketchup on a slice of bread.

2. Cover the sauce with cheese.

3. Place it in the oven until the cheese melts.

What happened?

Draw a picture of your bread before and while it was put in the oven.

What did I learn?

1. What did the radiation from the oven do to the cheese snack?

___________________________________________________________

2. How is radiation different to conduction and convection?

___________________________________________________________

3. Draw the electromagnetic waves in your second picture above.

What’s my target?

Heat can be transferred by radiation. This is when the heat energy moves in the form of electromagnetic waves. The sun sends out radiation. Other hot objects, like fires and light bulbs, also send out radiation that heats objects up. Radiation is different to conduction and convection because it does not depend on the movement of particles.

The sun’s radiation travels at 300 million meters per second.

Things I need:

Slice of bread Ketchup Slice of cheese Plastic knife Oven

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What do I need to do?

1. Look at the size and shape of the corn kernels.

2. Put the corn kernels in the popcorn maker.

3. Look at the size and shape of the corn kernels as they are heated. What happened?

Draw a picture showing before and after the kernel popped. Label the pericarp.

What did I learn?

1. What is the outside of a corn kernel called? ___________________________________________________________

2. What causes the corn kernel to explode? ___________________________________________________________ ___________________________________________________________

What’s my target?

The outside of a corn kernel is called the pericarp, which helps to keep a small amount of water inside the kernel. As the water is heated, it begins to change into a gas. The gas starts to expand and the pressure inside the kernel created by the evaporating water causes the pericarp to explode open and turns the kernel inside out. The sound that you hear is a “pop,” which is the gas escaping as the pericarp breaks. This is how popcorn got its name.

Things I need:

Popcorn maker Corn kernels

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What do I need to do?

1. Set up a cotton candy maker. Turn it on and wait for it to warm up.

2. Insert the candy inside the machine.

3. Twirl a chopstick around the large outer bowl.

What happened?

Illustrate how the cotton candy machine worked.

What did I learn?

1. How did the candy melt?

___________________________________________________________

2. Why doesn’t the sugar turn into crystals when it exits the spinning head?

___________________________________________________________

___________________________________________________________

What’s my target?

Cotton candy machines are used at many festivals. As sugar is put inside the machine, the electronic heating element transfers heat to the sugar and melts it into syrup. The machine rotates quickly which forces the syrup through tiny holes that lead to a large outer bowl. As the syrup exits the tiny holes, it transfers its heat to the air so quickly that the sugar particles don’t have time to turn into crystals. The end result is like a fluffy pillow that melts in your mouth.

Things I need:

Cotton candy maker Hard candy Chopstick

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What’s my target?

The time in which something melts depends on the materials or the amount of a particular ingredient used to make it. For example, this difference can be seen with milk chocolate and dark chocolate.

Dark chocolate contains more cocoa powder than milk chocolate. The cocoa powder amount affects the speed at which chocolate melts. Milk chocolate has more fats than dark chocolate. This also has an effect on how fast chocolate will melt.

Things I need:

Milk chocolate Dark chocolate Stopwatch Plate

What do I need to do?

1. Put a piece of milk chocolate in your mouth. You can suck on it, but don’t chew it. Time how long it takes to melt. Record your result in the chart below.

2. Put a piece of dark chocolate in your mouth. You can suck on it, but don’t chew it. Time how long it takes to melt. Record your result in the chart below.

3. EXTRA: See if you get similar results when putting a milk chocolate piece and dark chocolate piece under the direct sun. Time it and record your results in the chart.

What happened?

What did I learn?

1. Which type of chocolate melted faster in your mouth? Why did this happen?

___________________________________________________________

___________________________________________________________

2. Which method of heat transfer caused the chocolate in your mouth to heat up?

___________________________________________________________

3. Which method of heat transfer caused the chocolate under the sun to heat up?

___________________________________________________________

Chocolate Type Time in mouth to melt Time in sun to melt Milk Dark

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