By Susan M. Frack and Scott Prickett
As sunlight reaches the earth's surface it causes the surface to heat up. When the sun sets, the ground quickly loses that same heat while water loses the heat at a much slower rate. The earth's atmosphere is then heated by the processes of conduction and convection from the heat absorbed/reflected by the earth's ground and water surfaces. These processes are called "sensible heating" The atmosphere is also heated/cooled as the earth's water itself is either condensed or vaporized. This process is known as "latent heating".
Thermometers are used to measure the changes in temperature of the atmosphere. A thermograph is a continuous record of temperatures taken over a given period of time to show highest and lowest temperatures reached during that measurement period.
|Nat. Sci. Obj.||1.||demonstrate how a thermometer works.|
|A,B||2.||practice using a max/min thermometer.|
|D,E,G||3.||construct a thermograph for maximum and minimum temperatures for the 2-week FMP.|
|4.||illustrate how the earth's atmosphere is heated by convection and conduction currents and evaporation of water.|
- max/min thermometer
- student thermometers
- lamp with 150 w light bulb
- foil pans
- graph paper
- colored pencils
- poster board
Set up a demonstration lab as follows:
A. Under the 150w bulb, place 1 beaker with 150 ml of water and a thermometer and 1 beaker filled with 150 ml of soil and a thermometer. Turn on light for 10 minutes.
B. Fill the foil pan with ice. Set l beaker filled with 150 ml of water and a thermometer and 1 beaker filled with 150 ml of soil and a thermometer in the ice. Leave for 10 minutes.
Ask for volunteers to read and record on the board, the temperature of each container. Have students make observations about the temperatures. Then list questions/ inferences/conclusions they have about those observations. Let them know that they are going to try to answer those questions about the temperatures in the following activities.
1. Review/discuss how a thermometer works--see your textbook or encyclopedia for help. Complete the lab: Finding Temperatures .(Appendix A)
2. Teach how to use the max/min thermometer. Use the directions that come with your thermometer as well as the STEDII Hyper Studio program on measurements as references. *Students in grades 4-5 may wish to only measure the current outside air temperatures. . Max/min temperature may be too involved. Keep track of the daily temperatures on the Weather Log sheet for 2 weeks.
3. Lead a class discussion on the purpose of recording temperatures:
- weather prediction
- climate trends
- when to plant, harvest, fertilize, etc.
- product spoilage--when is refrigeration/heating necessary
- human/animal dangers--too hot? too cold?
Discuss the need than to get a better "picture" of temperature data by graphing it. Explain the graph of the temperatures can be called a "thermograph". Teach students how to make the graph. It is a line graph with one set of coordinates plotted and connected for the max. temperature and a second set of coordinates plotted and connected for the min. temperature. Both lines should appear on the same graph for easier comparison. Complete the activity, "Going to Extremes". (Appendix B)
Additional activities: Isotherms in the Classroom--Appendix C
4. Use overheads(Appendix D) to teach about where the earth's heat energy comes from. Use a globe and a flashlight to demonstrate the difference in types of sun rays the earth receives during the 4 seasons. Use Activity A from grades 4 and 5. Use Activity B for grades 6-7-8. (Appendix E)
5. Define these terms with the class:
- conduction--direct transfer of heat in a substance by the collision of rapidly
- moving molecules.
- convection--vertical transfer of heat by circular movements of large groups of
- *evaporation/condensation--molecules change from liquid to gas and back again
- thus creating heat loss or gain
*may be too difficult for younger students to understand.
6. Divide the students into groups of 6.* Then subdivide each group of 6 into 3 groups of 2 people. Assign each group of two people one of the 3 heat transfer topics. They will prepare a poster and short oral report (Appendix F) for the other 4 members of their group. They will need to conduct some research into their topic to be able to do a credible job. Information can be found in many different resources. Ask the media specialist to help locate and collect these resources for you in your own media center. * If you are only investigating conduction and convection, just divide the class into groups of 4 instead of 6.
7. Have students complete the poster activity and display their posters around the classroom/school for all to see.
- Solar Energy Crossword
- Solar energy Word search (all found in Appendix G)
- Convection Current Lab
- Have students create a video or poster that:
- shows how to use a thermometer.
- shows how to make a line graph to graph temperature.
- shows why the earth's surface is heated unevenly by the sun.
- Give a test or quiz.
- Celsius thermometers
What to do:
1. Stand the thermometer in the empty beaker for 5 minutes. Record the temperature of the air:________________________
2. Fill the beaker half full of ice and water. Let the beaker stand for 5 minutes. Then place the thermometer in the beaker for 1 minute. Record the temperature.____________
3. Fill a second beaker half full of tap water and add the thermometer. Let it set for 5 minutes. Record the temperature.
1. How much warmer ws the room temperature than the temperature of the ice water?
2. Was the tap water warmer or cooler than the room temperature? Explain:
3. Why did you need to let the thermometers set in their location for several minutes before reading the temperatures?
4. Why do you think water is not used as the liquid in many thermometers?
GOING TO EXTREMES?? (OR JUST TO TUCSON?)
Patty was exited! She was going to visit her aunt in Tucson, Arizona for a week in September. Only 1 thing bothered Patty, what was the temperature like in Tucson? What kind of clothes should she pack for the so she would be comfortable in Tucson. She surely couldn't take all of her clothes. Patty decided to keep track of the high and low temperatures in Tucson for 2 weeks. Maybe this data could help her decide what clothes to pack for the trip.
Patty's Temperature Log (in degrees Celcius):
Help Patty graph her data to get a better "picture" of the temperature extremes in Tucson. Use a red pencil to graph the high temperatures and a blue pencil to graph the low temperatures.
1. What was the highest temperature?_______________ Lowest Temperature?_______
2. What is the difference between these 2 temperatures?__________________
3. List 3 to 5 items of clothing that Patty should pack to help make her stay in Tucson's temperatures the most comfortable. **HINT She doesn't want to be too hot or too cold at any time of the day.
After each item, give 1 reason for its selection.
EXAMPLE: fur hat--it will keep her head warm on days when the temperature is below zero.
ISOTHERMS IN THE CLASSROOM
A typical weather map has lines drawn on it to show air temperature and air pressure. Your "map" of the classroom will have lines of temperature drawn on it. Your room will have its own unique microweather!! Drafts, open windows, doors, and movements by you and the air will show that the temperature of your classroom is certainly not constant.
To observe the different areas of temperature throughout your classroom.
- 21 thermometers
- colored pencils
- room diagrams
- Work in groups of 2 and place 2 thermometers in any 2 locations indicated on the charts. There are cards placed around the room to indicate where you should put the thermometers. Cooperate with the other groups so that 1 thermometer gets placed in each of the numbered locations.
- Open the door and 1 window on the opposite side of the room from the door. If your classroom doesn't have a window, start a fan on low on the opposite side of the room from the door.
- Wait 10 minutes before recording the temperatures of the room in the different locations. Then record the temperature of each location on the room diagrams.
- Use a red pencil to draw to draw lines on the 1-7 chart; a blue pencil for the lines on the 8-14 diagram; and a green pencil for the lines on the 15-21 diagram. Draw the lines according to the following rules:
- connect all equal temperatures with a smooth line. These are isolines.
- each end of a line must start and stop at a wall or make a complete circle.
- 1 line may not cross another line.
- 1 line may not stop/start at another line.
- if a temperature is completely surrounded by different temperatures, draw a ring around that station's temperature to show that the temperature only exists in that one place.
1. As height increases in the room, does the temperature increase or decrease?
2. How does the temperature at the floor near the door entrance compare to the back of the classroom near the wall?
3. Where is the warmest region in the room?___________________________ Why?
4. Where is the coldest region in the room?____________________________ Why?
5. Are there any isolated temperatures in the room?_____________ Explain:
6. If you were to use isotherms to map the school ground, would you come up with similar patterns to the classroom?_______________ Explain your answer:
GOING FURTHER: Average the temperatures from each group for each location and record on the diagrams. Make an overhead of the information and draw the isotherms. Have each group compare their diagrams to the class averages and discuss similarities and differences as a class.
The sun's energy radiates to the earth in different forms. About 1/2 travels as visible light rays. The other 1/2 travels as invisible ultraviolet and infrared rays.
About 1/3 of the ultraviolet and infrared rays are reflected back into space. The remaining 2/3 are absorbed by the atmosphere and the earth's surface. They warm the earth and make it a hospitable place for living things
Ultraviolet radiation is important to the earth because it stimulates the production of vitamin D. It can cause sunburns!
VISABLE LIGHT RAYS
These are the colors and images that we see every day. They are used for photosynthesis.
Infrared rays are the actual "heat waves". They are absorbed by the atmosphere or reflected back into space.
Ultraviolet and infrared rays are absorbed by the earth during a process called insolation. This process radiates heat back into the atmosphere from the surface of the earth. At the equator, insolation is 2 1/2 times greater than it is at the poles.
- 50% is absorbed by the earth's surface and changed into heat.
- 20% is absorbed by the atmosphere.
- 30% is reflected back into space.
- A. Reflected back into space by different particles in the upper atmosphere.
- B. Reflected by dust and water droplets (clouds) and scattered throughout the troposphere.
- C. Absorbed by the earth's surface and radiated out as heat.
- D. Absorbed by clouds.
- E. Absorbed by the ozone in the stratosphere.
Activity A: HEAT ENERGY
ADAPTED FROM: Prentice Hall Earth Science, Prentice Hall, Inc., 1991.
Heat energy that falls on different locations on the earth varies at any given time of the year. This can be tested using the following steps:
1. Using a large globe, tape one of three small thermometers at the equator, at 40 degrees latitude, and at the North Pole. Be sure the globe is tipped at the correct angle for the season you are currently in.
2. Shine a 250 watt light bulb, located 20 cm away from the globe, directly on the equator. The light from the bulb represents the radiant energy from the sun.
this bulb gets very hot. Watch students carefully as well as caution them of it.
3. Record the temperature of each thermometer at 2-minute intervals for 1 hour. Graph your results. Use a different colored pencil to represent each thermometer. Put the time on the y-axis(up) and the temperature on the x-axis(across).
- Which location got the warmest/received the most heat? __________________
- Which location stayed the coolest/received the least heat? __________________
- Explain your answers from 1 and 2:
Now tip the globe to the opposite season you just were in. Repeat the heating process and graph the results.
|time/sec equator 40 degree N.Pole||time/sec equator 40 degree N. pole|
- Which location got the warmest? ___________________
- Which location stayed the coolest? _________________
- Explain your answers from 1 and 2.
- Where there any differences between the current season temperatures and the opposite season temperatures? ___________What were they?
- Explain why there were differences:
Heat for the atmosphere comes from the radiant energy emitted by the sun. The sun’s energy reaches Earth as sunlight. Energy waves are absorbed by the Earth and returned to the air as heat energy. However, only a part of the sun’s radiant energy ever reaches the Earth. Use the diagram below to answer the questions about the factors that control how much energy Earth receives from the sun.
1. What percent of radiation is lost before it reaches the clouds or the surface?
2. The actual amount of radiation that reaches the earth’s surface and is absorbed, varies from day to day. What is the maximum percent of incoming radiation that could reach the surface
3. Describe a situation where the earth’s surface would receive the maximum amount of radiation during 1 day:
The minimum amount of radiation:
4. Which atmospheric condition has the greatest effect on incoming radiation?
*5. Which factor appears to have the least effect on the amount of energy that the earth receives?
6. What is the total percent loss from: water vapor, maximum cloud cover, and ozone?
Do some research to find out exactly how much of an effect the ozone layer does have on incoming radiation.
HEAT TRANSFER POSTER
Your topic is__________________________________.
Use the resources gathered by your teacher to discover what it is. Be able to describe it to your classmates by making a poster and an oral presentation. Include the following information on your poster and in your oral report:
definition of the term-- 6 points
explanation of how the heat is transferred by this method. Include drawing/diagrams-- 20 points
2 examples with drawings of the process-- 16 points
Is the process helpful to the earth? why or why not? -- 8 points
total points -- 50 points
YOUR SCORE ______________
ADAPTED FROM: Convection Currents by Alan Gold, LHS GEMS, University of California/Berkeley, 1988
Welcome to the ES Navy! (Earth Science--get it!?!) Imagine you are in a submarine that is stuck at the bottom of the ocean. Your submarine has no power to move itself up or down, but can propel; itself horizontally. Your mission, should you decide to accept, is to figure out how to get the submarine safely to the surface. First you will conduct several experiments using food coloring to trace the currents that are formed when a liquid is heated unevenly. These experiments will help you solve the problem of your stranded submarine.
- 4 foam cups
- 1 clear, plastic pan--available in the houseplant department, used to hold indoor pots so they don’t leak and leave rings on tables.
- boiling water
- food coloring
- eye dropper
- 50 ml beaker
- Place three foam cups upside down in the proper locations as shown in the diagram on the last page. In some trials you will have a cup of boiling water sitting in the middle of the upside down cups.
- Place the empty pan on the top of the cups.
- Fill the pan half full of room temperature water using the beaker.
- Let the pan sit quietly for 2 minutes to get rid of any motion currents created by filling it.
- Dip the dropper into the food coloring and draw a very small amount into the dropper. Move the dropper straight down in the pan of water to minimize stirring up the water.
- The tip of the dropper should just touch the bottom of the pan. Release the smallest possible drop and remove the dropper slowly.
Now complete Trials A through D and answer the questions under Conclusions.
Use the 3 upside down cups but no boiling water in the center. Place the drop of drop color in the center of pan right on the bottom. Draw what happens to the drop as you look at it from the top and from the side and write a brief description of what you see next to your drawings:
Use the 3 foam cups and the cup with the boiling water in the center. Replace the pan and refill with room temperature water. Place the drop of food coloring at the center of the pan on the bottom. Draw and record your observations as before in Trail A. Empty the pan of water when done.
Use the 3 upside down cups and the cup in the middle filled 3/4 full of boiling water. Replace the pan and refill it with room temperature water. Place the drop of food coloring on the bottom of the pan half way between the center and the edge of the pan. Draw and record as before. Gently stir the water when done and let it sit for 2 minutes.
Use the 3 upside down cups and the boiling water in the center. Place one drop of food coloring on the bottom of the pan in the center and a 2nd drop on the bottom near the edge. Draw and record as before. Carefully dump the pan of water and clean up after this trial.
- Which way does the water/color move over the boiling water (heat source)?________
- What happens to the heated water/color when it gets to surface over the heat source?
- What happens to the heated water/color when it reaches the edge of the pan?
- Which way does the water/color move along the bottom of the pan when placed near the edge?