Lesson Plan Template: Guided or Open Inquiry
Learning Objectives: What will students know and be able to do as a result of this lesson?
Students will learn:
- Not all surfaces reflect and absorb light equally. Higher reflective surfaces reflect more light away than lower reflective surfaces, therefore, lower reflective surfaces absorb more light and thus become warmer than higher reflective surfaces when both are exposed to the same sunlight intensity.
- Light energy from the Sun heats the Earth’s atmosphere indirectly. First it strikes the Earth’s surface and warms it. The air adjacent to the Earth’s surface is then warmed in turn.
- Therefore, the amount of incoming light which can be absorbed by the Earth’s surface is a major factor in the amount of heat which will be transferred into the air and affect the air temperature.
- Sunlight has energy which manifests as heat when it is absorbed by objects.
- Reflection of sunlight sends the sun’s potential energy away in another direction.
- Reflection (of light)
- LUX - units used to measure light intensity.
Note: at this grade level the experiment is designed to produce empirical evidence that air temperature is influenced by the degree of solar energy absorbed by the Earth’s surface and nearby objects. However, the specific heat transfer mechanisms of radiation, conduction, and convection are covered in detail at higher grade levels.
Prior Knowledge: What prior knowledge should students have for this lesson?
Investigate by observing and measuring that the Sun's Energy directly and indirectly warms the water, land, and air.
Identify the Sun as a star that emits energy; some of it in the form of light.
Show that the radiant energy from the Sun can heat objects.
Demonstrate that light can be reflected, refracted, and absorbed.
Investigate and describe that energy has the ability to cause motion or create change.
Investigate and describe some basic forms of energy, including light, heat, sound, electrical, chemical, and mechanical.
Students should recognize that heat flows from a hot object to a cold object and that heat flow may cause materials to change temperature.
Guiding Questions: What are the guiding questions for this lesson?
- What causes the air to change temperature?
- How does sunlight warm the air?
- How can sunlight be captured and converted to energy?
- Why does the warmest part of a sunny day occur later in the afternoon instead at around noon when the sunlight is striking the Earth most directly?
Introduction: How will the teacher inform students of the intent of the lesson? How will students understand or develop an investigable question?
Lesson opener/attention getter
Heat energy on Earth comes from the Sun. Since air is nearly invisible, it absorbs very little heat directly from the Sun.
The Sun’s rays pass through the atmosphere until they strike the Earth’s surface. The Earth’s surface absorbs the Sun’s rays and it warms up. The air is then warmed by the Earth’s surface.
We can have different temperatures on Earth depending on how much solar radiation the surface of the Earth absorbs at any given location.
Key talking points about the lesson topic
Start the session by presenting the information found in PowerPointTemperatureLesson1-HowDoesAirWarmUp. This will provide the background to enable the students to interpret the results of their experiments.
Investigate: What will the teacher do to give students an opportunity to develop, try, revise, and implement their own methods to gather data?
Get two identical white golf balls. Paint one flat black, leave the other white.
Place the white golf ball into one jar and the black golf ball in the other jar. Place the two jars with golf balls and in equal shade and give them a few minutes to reach a stable temperature. Note there may be slight differences in temperature and light readings between the two jars even when left in the same conditions for a while. This is because no two sensors will give identical readings, therefore, the difference in temperatures at the start of the experiment must be noted and taken into account during the experiment (See figure below for actual experiment data).
Note: this experiment requires strong sunlight for best results as the goal of the experiment is to produce distinct differences in air temperature between the two jars containing different colored surfaces.
If you are experiencing diffused sunlight due to haze or an early/late time of day, you can place a white piece of paper/cardboard in the jar with the white golf ball and a similar black piece in the jar with the black golf ball as shown in the figure 1. This adds to the amount of reflective / absorptive surface area exposed to the Sun. This helps create a larger temperature difference between the two jars in weaker sunlight conditions. See the figure below.
Attach the Climate Sensors to the lids of the jars using blue tack or double sided tape:
Have StudentWorksheet-HowDoesAirWarmUp ready to record temperature and light sensor values during the experiments.
Detailed instructions on how to conduct the experiment are found in StudentWorksheet-HowDoesAirWarmUp.
Analyze: How will the teacher help students determine a way to represent, analyze, and interpret the data they collect?
Instructions to help students organize, analyze, and interpret their data
Students will record the temperature and light readings and answer questions in the Student Worksheet.
How will you check for student understanding?
Students will be guided through questions in the Student Worksheet to express their conclusion about the causes of temperature difference.
Example data from an actual experiment:
This experiment was conducted during variable sunlight due to clouds passing overhead. Direct sunlight is preferable, however, the phenomena can still be observed here:
Experiment 1: students should deduce that the white surface is reflecting more light as this is evidenced by the higher LUX values given by the light sensor. Likewise, the black surface is reflecting less light, therefore, absorbing more light as evidenced by the lower LUX values given by the light sensor.
Experiment 2: The jar with the black golf ball should reach a higher air temperature as the black golf ball has absorbed more solar radiation and thus became warmer than the white golf ball.
In general, lower reflective objects will absorb more light and thus become warmer than highly reflective objects.
Warmth from the golf balls will be transferred to the air causing its temperature to increase. Since the black golf ball absorbed more of the sun’s energy than the white golf ball, its temperature is warmer, therefore, its surrounding air temperature will be warmer.
Experiment 3: The air in the jar with the black golf ball should take longer to cool as the ball will continue to emit heat after the direct sunlight has stopped. This is because it had absorbed more energy than the white golf ball during its time under direct sunlight.
How will you check for student understanding?
In the Student Worksheet questions are asked about the cause of difference in air temperature between the two jars given that they are both are receiving the same amount of sunlight and are identical in every way except for the color of the golf ball.
Common errors/misconceptions to anticipate and how to respond
Students may incorrectly think that the sun is directly heating the air within the jar and not realize that heat from the surface of the golf ball is influencing the temperature of the air. In the Student Worksheet they are asked to identify any differences between the two jars at the start of the experiment to focus them on the fact that the conditions influencing both jars are identical in every way except for the colors of the golf balls.
Students may incorrectly conclude that the reflectivity of light colors are inherently cool and the reflectivity of dark colors inherently warm regardless of whether being exposed to light energy. If experiment 3 is allowed to run long enough so that both jars become nearly equal temperature in the shade, then students will observe that in the absence of light energy the reflectivity of the golf balls does not affect the jar temperatures differently.
Closure: What will the teacher do to bring the lesson to a close? How will the students make sense of the investigation?
Revisit the lesson slides with the aim to have the students express the connection between the assertions in the slides and the empirical evidence produced by the experiment.
This experiment demonstrates the following phenomena:
- Surfaces of differing reflectivity absorb and reflect different percentages of available direct sunlight.
- Reflectivity has an effect on the how much light energy is absorbed by an object. The absorbed light energy manifests as heat.
- Air is warmed by the surface temperature of neighboring objects much more so than from direct sunlight.
Students will be guided through questions in StudentWorksheet-HowDoesAirWarmUp to express their conclusion about the causes of temperature difference.
The StudentWorksheet-HowDoesAirWarmUp worksheet can be evaluated for understanding of the phenomena.
Feedback to Students
the StudentWorksheet-HowDoesAirWarmUp worksheet provides students with a means to demonstrate their understanding and receive feedback from the teacher when necessary.