Summer Days, Winter Nights:
Planetarium show for Middle School Children
Post-Show Activity 2
Seattle, Singapore, Sydney

Objectives
• Students will understand how the earth's revolution and tilting effect the seasons.
• Students will compare and contrast the different seasons in Seattle, Singapore, and Sydney.
2 - 5

Materials
• Globes
• Light sources, lamps or flashlights
Background

This is a two-day lesson with an option to extend for weeks. First distribute globes and have students find Seattle, Singapore, and Sydney on the globe.

Procedure
1. Engagement: Ask students what season it currently is in Seattle. Do all parts of the world have the same season at the same time? In whole-class discussion, help students identify what they already know about what causes the seasons to change.
2. Exploration: Display a globe and review with students these concepts: the North Pole, South Pole, equator, northern hemisphere, and southern hemisphere. Find Seattle, Singapore, and Sydney. Mark each with a small piece of colored tape. Which hemisphere are these cities located in? Which city is closer to the equator?
3. Explanation: Point out how the earth is tilted and not in a straight up and down position.

Explain that the earth's axis is an imaginary line from the North Pole to the South Pole and that this axis is tilted (at 23 1/2°), causing parts of the earth to get more radiant energy than others. Simulate the sun by using a 100-watt bulb or a flashlight. Show how in summer the northern hemisphere is tilted toward the sun. It receives more direct, concentrated rays and has longer periods of sunlight. Therefore, it has longer days and shorter nights than the southern hemisphere, which is experiencing winter. Six months later the southern hemisphere is tilted toward the sun and it is enjoying summer. Explain and show that in spring and fall the sunshine is shared equally between the northern and southern hemispheres.
4. Independent Practice: Divide the classroom into cooperative learning groups of three to four students. Provide each team with a globe, a light source bulb or a flashlight, and some colored masking tape. Direct students to locate the poles, equator, Seattle, Singapore, and Sydney. Using the light source, have each team simulate the various seasons for Seattle. Have students find and identify other cities or countries on the globe and demonstrate the various seasons. Be sure to include places in both hemispheres. Discuss the climate in Singapore. Why would you guess it stays warm all year long?

Lesson Procedure - Day 2:
1. Engagement: Ask students questions to determine their understanding of the concepts taught on Day 1. What season do you think our friends in Sydney, Australia are having now? How do you know? Is Singapore having the same season? Why? Which city is closer to the equator? How do you think this will affect the temperature? What other conditions might affect the temperature of the region?
2. Exploration: Have the students divide into their cooperative learning groups. Provide each team with a globe and a light source or a flashlight. Locate Seattle on the globe. Using the light source, have each team simulate the various seasons for Seattle. What can they discover about the slant and intensity of the sun's rays during each season?
3. Explanation: Point out that countries along the equator such as Singapore have no clearly marked seasons. It is hot all year round because the equator is closest to the sun and receives direct solar energy. Show how the opposite is true of locations near the poles where it is cool in the summer months because the sun's rays are indirect and farthest from the sun. Explain that in Singapore there is no winter and summer as such but instead one hot dry season and one hot wet season. The dry season runs from April to September and the rainy season from October to March.
4. Independent Practice: Using the globes, have students show and explain why Costa Rica does not experience summer and winter. Have students find and identify other cities or countries on the globe and demonstrate the various seasons. Suggested places to find might be London, Denver, Miami, Alaska, Panama, New Dehli, Cape Town, Greenland, Paris, Nicaragua, Kenya, Tokyo, Hawaii, Venezuela, and Argentina. If using topographical globes, have students predict whether the temperature will be hot or cold according to elevation. How will distance from the equator affect temperature?