Seasons Investigations
Activate prior knowledge about seasons and sunlight.
Earth orbits an ideal distance from the sun, and this affects the weather we experience here on Earth.
1. What are the different seasons?
2. What is the weather like during the different seasons?
3. What is the same or different about the seasons? (Include similarities and differences in weather, temperature, and length of daylight)
4. Do these seasons and factors differ by location on Earth?
5. What do you think causes the difference in seasons?
6. What do you think causes the difference in what time it gets dark outside?
Reason for the Seasons Video
2. Build background about what causes seasons.
The Earth rotates on an axis that is tilted. In other words, our planet never stands upright—it is always leaning to the side. The direction of this lean does not change significantly over the course of a year, but it does shift gradually over millennia. As the Earth travels along its orbit, it sometimes leans toward the sun and sometimes away from the sun. If you live in the Northern Hemisphere, you live on the part of the Earth that is north of the Equator. When the Northern Hemisphere is tilted toward the sun, you experience summer. When the Northern Hemisphere is tilted away from the sun, you experience winter.
1. How would this change if you lived in the Southern Hemisphere?
3. Hands-on activity.
In groups of three.
Materials: one polystyrene foam ball, one marker, one flashlight, and two pushpins.
1. Choose who will hold the foam ball that represents the Earth and who will hold the flashlight that represents the sun.
2. The student holding the Earth, draw a circle around its middle to represent the Equator, and dots on the North Pole and South Pole.
3. Have the third group member place a pushpin, representing a person, midway between the Equator and the North Pole, and another between the Equator and South Pole.
4. Place both pushpins on the same side of their Earth.
5. The Earth moves around the sun in an elliptical orbit and is tilted on its axis. As Earth orbits the sun, it rotates on its axis, and the axis is always pointed in the same direction.
(Stand approximately 5-7 feet apart. Dim or turn off the lights.)
4. Use guided inquiry to investigate direct and indirect sunlight.
1. The student acting as the sun keep the flashlight pointed straight at the representation of Earth while the student holding Earth walks in a circle around the sun.
2. The Earth should stop when the pushpin representing a person in the Northern Hemisphere can "see" the sun.
3. The student holding Earth to tilt the Earth so that the sun, without moving the flashlight, is shining directly overhead of the pushpin/person in the north.
1. Is the sun more direct for the person at the top or the person at the bottom of the Earth?
2. Do you think it is warmer for the person at the top or the person at the bottom of the Earth?
3. Why do you think so?
5. MISCONCEPTIONS: One common student misconception is that this is due to the Northern Hemisphere being closer to the sun. Note that there is no significant difference in the distance of the sun to the Northern and Southern Hemispheres. The difference is due to direct and indirect solar radiation. The hemisphere that is pointed toward the sun receives more direct solar radiation, thus it is warmer.
1. Is the sun more direct, or bright, for the person in the Northern Hemisphere or the Southern Hemisphere?
2. Which person do you think feels warmer temperatures?
3. Why?
6. Role of axis and tilt in the sun-Earth relationship.
1. While the sun is still shining directly overhead of the pushpin/person in the Southern Hemisphere, locate where in the classroom, such as a wall or ceiling, the North Pole points to (See the black circle on the wall?).
2. The Earth to resume orbiting the sun, while keeping the North Pole pointed at the black circle.
3. Keep the sun stationary and pointed at Earth, everyone else, help to make sure the Earth’s tilt doesn't change. The Earth's tilt does not change significantly over the course of a year, but does shift gradually over millennia.
4. Stop the Earth after one-half of an orbit so that it is opposite of where it started.
5. One group member, make it daytime for the “top” and “bottom” people. It should be night for them if the Earth has orbited correctly.
6. Groups move the Earth half an orbit around the sun again, making sure to keep the North Pole pointed at the black circle. Make sure the sun does not move. Also, ensure as the Earth orbits the sun, the axis does not change orientation and continues pointing to the black circle. Have a group member make it daytime for the “top” and “bottom” people.
1. Does the sun shine more directly on the person on the top half of the Earth, or the person on the bottom half?
2. Which person feels warmer temperatures?
3. Which person is experiencing summer? Winter?
4. How do you know?
5. Is the sun brighter or more concentrated for the person in summer or the person in winter? (the person in summer)
7. Math connection.
8. Whole-class discussion
Seasons are opposite for people on the top (north) of the Earth and on the bottom (south) of the Earth.
- 1. When it is winter on the top (north) of the Earth, what season is it on the bottom (south) of the Earth?
- 2. When it is winter on the bottom (south) of the Earth, what season is it on the top (north) of the Earth?
- 3. How can we use angles to help others to understand seasons?
Informal Assessment
Orally explain how the interaction between the sun and Earth affects seasons here on Earth, and what happens with the sun's rays during the different seasons. Use vocabulary terms axis, tilt, direct sunlight, and indirect sunlight in your responses.