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Earth’s Tilted Axis

E a r t h ’ s T i l t e d A x i s 1© Teachers’ Curriculum Institute

T H E E A R T H - S U N - M O O N S Y S T E M

O B S E R V I N G P H E N O M E N A

1. What questions do you have about this phenomenon?

Phenomenon: Each year, trees sprout leaves which grow, change color, die, and fall off.

2. Record three observable patterns in seasonal changes.

Pattern 1

Pattern 2

Pattern 3

3. What do you think causes Earth’s seasons? Write your prediction below.

4. At each blue sphere, draw in Earth’s axis and label it. Afterward, revise your prediction to include the phrase “Earth’s tilt” somehow.

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2 E a r t h ’ s T i l t e d A x i s © Teachers’ Curriculum Institute

1. For each image below, complete the following: • lightly shade the side of Earth that is experiencing night• circle the area of Earth that is getting the most concentrated sunlight • label the month that Earth is in this orientation

2. How is the inflatable globe model used in class like the real world? What are some limitations of the model?

I N V E S T I G AT I O N 1

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E a r t h ’ s T i l t e d A x i s 3© Teachers’ Curriculum Institute

2. Describe the seasonal patterns that you have observed where you live.

1. Annotate the calendar below to show approximately when the four seasons occur during the year. Optional: Research when the first day of each season officially begins. Label it on the calendar.

1 - The Seasons

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4 E a r t h ’ s T i l t e d A x i s © Teachers’ Curriculum Institute

2. If the sun emits equal amounts of light in all directions, what conclusions can you draw about the intensity of the light on areas where sunlight is spread over more squares compared to areas where sunlight is spread over less squares?

3. How do the patterns in your data help explain why seasons occur?

Before you collect data, make a prediction about which location (latitude) on Earth experiences the most direct sunlight at each time of year. In the table below, in the Prediction column, write the latitude where you think sunlight will be the most concentrated for each time of the year.

1. Now, begin collecting your data. Record the number of squares illuminated by the flashlight when held at a 10 centimeter distance from the grid paper.

Location (Latitude)

PredictionTropic of Cancer

(Northern Hemisphere)

EquatorTropic of Capricorn

(Southern Hemisphere)

December Solstice

squares squares squares

March Equinox

squares squares squares

June Solstice

squares squares squares

September Equinox

squares squares squares

I N V E S T I G AT I O N 2

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E a r t h ’ s T i l t e d A x i s 5© Teachers’ Curriculum Institute

1. Earth is unevenly heated. On this image of Earth, label where the most concentrated sunlight hits Earth. Also, label where the least concentrated sunlight hits Earth.

2. Use your knowledge about sunlight and energy to explain why the climate is warmer near Earth’s equator and colder near the poles. Use the terms light, angle, concentrated, and diffuse in your response.

3. Recall that the Earth is tilted. (In the image above, Earth is tilted toward the viewer.) Sometimes the Northern Hemisphere is tilted toward the sun, other times the Southern Hemisphere is tilted toward the sun. Predict how this affects temperature variation on Earth.

2 - Earth’s Shape and the Sun’s Energy

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6 E a r t h ’ s T i l t e d A x i s © Teachers’ Curriculum Institute

1. Draw and label a picture of the Earth-sun system that includes Earth’s axis. Include the degrees that the axis is tilted relative to Earth’s orbital plane. (Recall that Earth’s axis always points towards Polaris.)

2. Provide an explanation for why this system results in the uneven heating on Earth.

3. Suppose Earth’s axis was not tilted. What would be the effect of this on temperature variation?

3 - Earth’s Tilted Axis and the Seasons

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E a r t h ’ s T i l t e d A x i s 7© Teachers’ Curriculum Institute

1. On this image of Earth, draw and label the Tropic of Cancer and the Tropic of Capricorn.

2. Which solstice is Earth experiencing in this image?

3. Summer is about to begin for your friend in South America, while you are preparing for winter. Explain to your friend why you experience opposite seasons.

4. Complete the table below.

June Solstice December Solstice

Which pole is tilted towards the sun?

The sun is directly overhead which tropic?

Which season is starting for the Northern Hemisphere?

4 - The Solstices

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8 E a r t h ’ s T i l t e d A x i s © Teachers’ Curriculum Institute

1. The word “equinox” comes from Latin and means “equal night.” Explain how all parts of the Earth receive 12 hours of daylight and 12 hours of darkness on these two days of the year.

2. Complete the table below.

September Equinox March Equinox

Which pole is tilted towards the sun?

Which season is starting for the Northern Hemisphere?

5 - The Equinoxes

I N V E S T I G AT I O N 3

1. Write down how you will explain what causes seasons to the two different audiences you will present your model to: a kindergartner and an adult. Your model must use the patterns that you have learned about to explain the following: December Solstice, June Solstice, March Equinox, September Equinox, tilt of Earth, position of the sun, solar energy, solstices, and equinoxes.

Explaining Seasons to Kindergartners

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E a r t h ’ s T i l t e d A x i s 9© Teachers’ Curriculum Institute

6 - The Seasons and the Sun’s Path in the Sky

2. Describe how your explanation for kindergartners differs from your explanation for adults.

Explaining Seasons to Adults

1. How does the length of a day change with the seasons? This answer will vary depending on where you live. Research the sunrise and sunset times for the first day of each season in your area. Record in the table below. Then, calculate the length of the day (the time between the sunrise and sunset).

SeasonFirst day of the season

Sunrise (estimate)

Sunset (estimate)

Length of Day

Summer am pm hours

Autumn am pm hours

Winter am pm hours

Spring am pm hours

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10 E a r t h ’ s T i l t e d A x i s © Teachers’ Curriculum Institute

2. What do you notice about the relationship between the season and the length of day?

3. Imagine you are standing on the horizon and facing south. Draw the arch of the path that the sun takes during the June solstice (first day of summer) and the December solstice (first day of winter). Label the two arches for each solstice.

Read the scenario below. Then answer the question that follows.

Suppose you are living in ancient times. Your people want to make a calendar to record the location of the sun throughout the seasons. But you do not have a written language, so you cannot use words or numbers! However, you could use outdoor structures or other natural materials. You want to make sure that your calendar can show the solstices and equinoxes.

1. Define the problem faced by ancient peoples by listing their criteria and constraints.

Criteria Constraints

7 - Calendars of Ancient Civilizations

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E a r t h ’ s T i l t e d A x i s 11© Teachers’ Curriculum Institute

2. A storyboard is a series of panels that shows the visual and verbal components of a video you intend to make. Create a storyboard that explains this phenomenon. It must • be one to two minutes in length.• provide an explanation of the causes of Earth’s seasons.• include evidence for this phenomenon.• include the terms: pattern, tilted axis, Earth’s surface, sunlight, Polaris, equinox, and solstice.

You may use any of the aspects of the models used in class and in the Student Text.

Visual Script

1 1

2 2

3 3

4 4

1. Use what you have learned to explain this phenomenon.

Phenomenon: Each year, trees sprout leaves which grow, change color, die, and fall off.

M A K I N G S E N S E O F P H E N O M E N A