CONDUCTION, CONVECTION, RADIATION, OH MY
Grades 6 - 8
In this lesson and its extension opportunities the students should have the opportunity to learn how to draw a line graph, and use graphing as a tool to discover more about conduction, convection and radiation. The students should design their own experiment using heat sensitive paper to show they understand conduction, convection and radiation, measure the rate of change in the classroom, and make conclusions about their efficiency. Previously the students should have talked about heat as a form of energy, have had some experience with bar graphs, and know how to write a rate fraction. It would help if the students have had some graphing experience with bar or line graphs (they should be able to locate points like battleship). This activity could be used to teach graphing but this would take more time.
"Bill Nye The Science Guy #109: Heat Trigonometric"
"Functions II #2: Amplitude and Period"
Students will be able to:
- describe and give examples of the three methods of heat transfer;
- graph class data and interpret it;
- using similar materials design three experiments to compare the rates of conduction; and convection, and radiation in the classroom.
"A Nifty Experiment" Activity
- water soluble markers
- 3 Hot plates with liter containers - to create hot water per group of three to four students
- one disposable plastic tray (one to two inches deep)
- one wooden ice cream stick
- one plastic knife
- one metal knife
- three pats of butter or margarine
- three sugar cubes or clay balls
- hot water
- 400 ml beaker
Conduction, Convection, Radiation Activity
per group of three to four students:
- one or two sheets of heat sensitive or mood paper
- 2 sheets thick plastic or glass (like a microscope slide)
- ice cube in plastic bag
- 3 pennies
- 2 Plastic Bags
- cooler with ice to cool heat sensitive paper
variable - the one part of an experiment that changes.
direct relationship - a relationship between the cause and effect where one increases as the other increases.
indirect relationship - a relationship between the cause and effect, where one decreases as the other increases.
X Axis - horizontal axis (the cause of an experiment or independent variable.)
Y Axis - vertical axis (the effect of an experiment or dependent variable.)<
conduction - a method by which heat is transferred from a warmer substance to a cooler substance by molecular collisions. The closer the molecules (solid) the better the transfer.
convection - a method by which heat is transferred by currents in a liquid or gas.
radiation - a method by which heat can be transferred through objects and empty space.
heat energy - total kinetic energy of the molecules or atoms of a substance.
infrared waves - heat waves.
Have the room set up in rows 1, 2, 3, 4, 5 etc. and columns A, B, C, D, E etc. Give the students a numbered letter card as they enter the room and have them find their new seats (B6 or F2) using labels on the wall. (Since the students are in groups, just leave empty spaces for the missing rows or columns). Also give each student a work sheet and ask them to write down everything they know about conduction, convection, and radiation.
Explain that they will be forming a graph using the cards given to them as they came in. Ask the following students to stand. A1, B2, C4, D5. They have formed a human graph. If the single people stand it is a line graph, while if the whole column stands it is a bar graph. Explain that you wish to look for relationships in this graph. Read out the numbers again. Ask the students to complete the following statement. As the numbers increase the letters ____. (increase) This
is called a direct relationship. As one goes up the other goes up. What would happen if one decreased? (other decreases)
Have the students form another graph by asking the following students to stand E1, D2, C3, B5. Ask the students to complete the following statement. As the numbers increase the letters ____. (decrease) This is called an indirect relationship. As one goes up the other goes down. What would happen if one decreases? (other increases)
The focus for viewing is a specific responsibility or task(s) that the students are responsible for doing, or after seeing video, to focus and engage students' viewing attention. This is a graph of the height of plants vs. temperature. As you watch this video it will be your responsibility to supply the narration and explain how this graph is being formed.
BEGIN the video Trigonometric Functions II #2 right before they do the sine plot. This is the screen that shows the values for 0 to 90 degrees at the top with the graph below. DO NOT USE SOUND. PAUSE instantly to have the students label the axis. Explain that this is a graph of temperature vs. the heights of plants. Ask which of these two values is the cause (temperature) and which of these two values is the effect (height). Explain that the cause goes on the X axis while the effect goes on the Y axis. Using dry markers that erase with water, have the students label these axes on the TV screen. (Please check to make sure the pens erase before using them.) Ask the students to plot the first point. RESUME the video and pause when the first point is plotted. Continue having the students predict, plot and check their value by playing the tape until you check each of the values. STOP after you check the value for 90 degrees. Explain that graphing is the language of science and we will use graphing to investigate conduction, convection, and radiation.
Today's lesson is called "Conduction, Convection, Radiation, OH MY." At the end of this class you should be able to:
1) Describe and give examples of the three methods of heat transfer
2) Graph class data and interpret it
3) Using similar materials design three experiments to compare the rates of conduction, convection, and radiation in the classroom.
As the students watch segments of Bill Nye The Science Guy #109: Heat Trigonometric it will be their responsibility to discover the three ways heat can be transferred and give examples of each. Begin the video on the screen saying "Heated Debate." PAUSE after "with your hosts Ray Deation, Connie Vection, and Conrad Duction." What were the three names they just gave us? What do these names tell us about heat transfer?
RESUME the video and stop at the end of the debate. What are the three ways heat can be transferred? Give examples of Radiation, Convection, Conduction. As they watch the next segment the students should focus on how these three methods of heat transfer can be used in the kitchen.
REWIND and BEGIN the video segment where Bill Nye is in the kitchen and he says, "Heat moves around the kitchen in three ways." PAUSE the video after he says "into a dry pancake." Ask, "What type of heat transfer is this?" RESUME the video and PAUSE after he says "the steam makes it hot, hot, hot." Ask, "What type of heat transfer is this?" RESUME the video. PAUSE the video after he says, "the flame cooks the marshmallows without anything touching anything." Ask, "What type of heat transfer is this?" Ask the students to check their responses as they watch the last segment. RESUME the video and stop after he says "Hmmm not bad." (this is right before the heated debate)
Have the students look at the brainstorming they did in the beginning of the period about conduction, convection, and radiation. Review briefly what they put on their sheets. What did they learn by watching the video segment? What did they already know? It will be the students' responsibility to set up and conduct the experiment they see on the screen with one or two modifications. That is their focus. Watch carefully.
FAST FORWARD and BEGIN the video at the title screen "A Nifty Experiment." STOP the video where the narrator says "put a sugar cube on top of each pat of butter." Ask how would you set up the experiment? How much hot water should we use? We will all use the same amount of water, 250 milliliters. We will pour the water into a tray and take the temperature. Set up all three knives at once and then time them to see how long they take to fall off. We will then plot the class results for each of the three knives. Have the students perform the experiment. (collect the data on the chalkboard or on flip charts)
Which value is the cause, Temperature or Time? (Temperature) Which value goes on the X axis? (Temperature) Which value goes on the Y axis? (Time) Is this a direct relationship or an indirect relationship? How can you tell? (As the temperature increases the time decreases.) Which knife heated faster? Why do you think it heated faster? What type of heat transfer is involved in this experiment? (explain your answer)
As the students watch the next segment, their focus should be to watch what Bill Nye is doing and predict what will happen. FAST FORWARD and BEGIN the video where Bill Nye lights the Bunsen burner under one end of a large convection cell. Begin after Bill Nye says "there is also natural convection - naturally." PAUSE where he says "so there are fewer molecules in the hot part of the tube." Now make a prediction. What will happen? Who has a prediction they wish to share with us? Tell it to your group first and agree on it before you raise your hand. How sure are you about your prediction? I will lower the sound and ask you to supply the narration. It will be everyone else's responsibility to check what this student is saying.
Turn off the sound and RESUME (this is done to show that the student has the full responsibility to explain the concept of convection, this also causes other students to pay attention for their turn could be next.) The student should explain that hot water goes up and cool water goes down forming circular pattern. PAUSE the video where the food coloring is being brought out. Ask the students for their comments. Is there any way we can prove what the last student just told us? What could this food coloring show us? Ask a new student to continue the narration. Ask the rest of the class to see if the student is correct. RESUME video and stop where he walks away from the convection cell. What type of heat transfer was that? How did you know? Were your predictions correct? Did our narrators make any mistakes? REWIND and PLAY again if necessary.
Watch this next segment for information to help you with your next experiment. You will be given heat sensitive paper that is similar to the heat sensitive camera in the next segment. Your focus is to discover how this heat sensitive camera can show conduction, convection, and radiation?
FAST FORWARD and BEGIN at the title screen "Way cool Scientist" and stop at the end of this segment. Where did you see conduction? Convection? Radiation?
Remember what you just saw. It is your task to design an experiment to show conduction. You are to design an experiment to show convection. You are to design an experiment to show Radiation. You may use part of or all the material in your basket. You are responsible to describe Radiation, Conduction, and Convection mathematically using rate. Rate is how long it takes to get something done. (Give the students one or two examples of rate and how to write them in fractions.)
Help the students perform the experiment by leading them through the activity. Go over the items in the basket. Ask which two items could be used to measure temperature change? (thermometer and mood paper) Ask what is conduction? How can you show conduction in the kitchen? How can you show conduction using the objects in the basket? These questions help the students clarify their thinking. Ask the same questions about convection and radiation.
Have the students write down what they want to do on a sheet of paper. Approve the experiment, and let them try it. Do this for conduction first, then convection, then radiation. Be flexible they may come up with radiation without knowing it. As you approve their ideas announce "we have one convection idea and one conduction idea who else is ready to be checked?" This will generate excitement.
The students should perform the three experiments. Remind them you also want rates. After the activity is done have them compare the rates of conduction, convection, and radiation. If they have to choose one method for heating their home, which would they choose and why? You will be watching a review about conduction, convection, and radiation. The students' focus is to determine what was left out of this review that they would have included? FAST FORWARD and BEGIN after a big sweaty guy says, "Molten Steel at 2900 degrees and that makes me hot." This will give you the beginning of the song which is in the last five minutes of the video. Continue to the end of the song and then STOP. What did they leave out of this review that you would have included?
Have a heating contractor visit the class to discuss ways in which houses can be heated and the efficiency of these systems.
Have a heating contractor visit the class to discuss solar heat.
Have a local fire house come to the class to discuss fire prevention and how knowledge of heat transfer is important to get out alive, or why a fire must be vented. The difference in temperature between the top of a room and the floor should also be discussed.
Math: Rate Problems. Predict if the cooling rate equals the heating rate of the
experiment. Compare the rates.
Science and Math: Using a similar set-up ask the students to pretend you are in
outer space and are wearing gloves. (supply gloves and consider showing the video
segment on a thermos) Have the students design three new experiments showing
conduction, convection, and radiation. How does the rate now compare?
Science: Have the students research, design, and build a solar heating panel for
Social Studies and Geography: How did early man heat and cool his dwellings?
Native Americans who live_north, south, east, or west, and other native peoples,
Social Studies: What clothing do we use for different climates and why? How
efficient is the clothing you wear? How did early peoples use clothing? Look at
the early expeditions to the North and South Poles.
Art and Science: Which colors will absorb the most heat. Design a house for
someone who lives near the equator and another house for someone who lives near
How does a radiator heat the room? Based on your knowledge of heat, design and
build a scale model of a room and locate the radiators.
Physical Education: Why do travelers who ski want to include a "space blanket" in their emergency kit? How does a space blanket work? Fire Safety and Science.
What do the drills for fire safety have to do with conduction, convection, and
radiation? Demonstrate getting out alive. How can fire be controlled? (Fuel,
Temperature, Oxygen) Kindling temperature. Spontaneous combustion.
Inventions: Sprinkler system, Heat sensitive elevator button, Thermostat
Master Teachers: Ainsley Adams and Christopher Ward
Click here to view the worksheet associated with this lesson.
NOTE TO TEACHER
Cholesteric liquid crystals will change color as they get warmer. Conduction can be shown by touching the pad and noting the results or by touching a penny and placing the penny on the pad. Convection can be shown by breathing on the pad or placing the pad two feet above an active radiator. Radiation can be shown by bringing the pad close to a warm object but separated by a plastic sheet or by putting the object in direct sun light or near a light in the classroom. To compare the rates for conduction touch the crystal paper and time the change to one color, for convection put the object above your skin and time the same change, for radiation put the object near your skin but use a plastic sheet to prevent convection and time the same change. These are one set of ideas. Once you start the ball rolling students will generate their own ideas.