What Causes the Different Seasons on Earth

What causes the different seasons on Earth?

Student Hand-out

1. Creating Initial Models (eliciting student’s prior knowledge). In the box below: a. Name the different seasons in the U.S. b. Draw and/or explain what you think causes these seasons. c. What is your evidence, rationale, or how do you know that?

1 2. Initial Observations (student’s gathering and/or using observational data)

a. Create a globe using Styrofoam ball or use an existing globe and flashlight. Ask students to put a stem wire or a stick in the middle of the globe to represent the axis. Secure the stem wire by sticking the bottom part to another Styrofoam or a cup of sand; making about 20 degrees tilt from 90 degrees (see diagram below).

Flashlight

b. Observe the amount of light that the North gets from the Sun as the Earth revolves around the Sun. Use the table below to draw and write your observations.

Side View

Note: Pictures & distances are not drawn to scale.

2 Write your observations and explanations below:

c. Experiment on spreading out. Hold the flashlight in one spot (1) directly and (2) at an angle. Draw your observations in the box below.

i. Which one do you think gets more light from the flashlight (and more heat)? Explain.

3 3. Get a heat lamp and 3 thermometers for each group. Set up the thermometer so that one will get a direct light from the lamp and one partial light. Record your observations and temperature (in degrees Celsius) for 5-10minutes.

Direct light from the lamp Indirect Light from the lamp

Time (min) Temperature (oC) Time (min) Temperature (oC)

Observation Questions:

a. What patterns did you see? b. What is the difference between the direct light and indirect light? c. How can you use this knowledge to explain the different seasons?

4 4. Revise your model. In the box below:

a. Name the different seasons in the U.S. d. Draw and/or explain what you think causes these seasons. e. What is your evidence, rationale, or how do you know that?

5 5. View the Sun Tracker. Use the ruler to measure the height or location of the Sun in the sky in the in 12 months.

Month How high is the sun in the sky? January February March April May June July August September October November December

What patterns did you see?

6 6. Global Sun Temperature Project i. Plot the latitude vs. average minutes of sunlight in the graph (during spring). Also note the average temperature in every location.

What patterns did you see? As you go north, what happens to: (a) the average minutes of sunlight and (b) the average temperature?

ii. Plot the latitude vs. average minutes of sunlight in the graph (during fall). Also note the average temperature in every location.

What patterns did you see? As you go north, what happens to: (a) the average minutes of sunlight and (b) the average temperature?

7 7. Revise your model. In the box below:

a. Name the different seasons in the U.S. b. Draw and/or explain what you think causes these seasons. c. What is your evidence, rationale, or how do you know that?

8 Quiz

1. If it is summer in United States, what season is it in Australia?

a. Spring b. Summer c. Autumn d. Winter

2. We have summer in the U.S. because…

a. The whole Earth is closer to the Sun than in winter making it warmer. b. The U.S. is closer to the Sun than in winter because of the Earth’s tilt, so the temperature rises. c. The part of the Earth where the U.S. is located is tilted towards the Sun. This means that the Sun’s rays are more focused on the U.S. This cause the temperature to rise.

3. It is winter in the U.S. because…

a. The Sun shines on us for a shorter time in winter than summer so we get less heat. b. The Sun’s rays reach us at an angle, “spreding-out” the heat over a larger part of the Earth. c. Both 1 and 2 d. None of the above

9 Analysis of Models: Building Analogies (think-pair-share; discussion of strengths and limitations of models)

Model Target Strength of the Analogy Weakness(es) or limitations of the Analogy i.e. flashlight Sun Flashlight is good to use to Flashlight doesn’t fully show how the Sun provides show the intensity and the light and how directions of light. The direct/indirect light from the light from the sun contains flashlight helps us study how different waves (uv, vis, the moon gets its light (initial etc.) and heat that makes step to study the phases of the flashlight not an exact the moon) replica.