GEMS Reasons for the Seasons project

(A) analyze, review, and critique scientific explanations, including hypotheses and theories, as to their strengths and weaknesses using scientific evidence and information;

(13) Science concepts. The student knows components of our solar system. The student is expected to:

(A) identify characteristics of objects in our solar system including the Sun, planets, meteorites, comets, asteroids, and moons; and

Concept Statement:

The shape of the Earth’s orbit around the sun is near a circular ellipse. By drawing ellipses for Pluto and Earth students will be able to identify the Earth’s orbit shape around the Sun.

Performance Objectives:

Students will be able to draw and define an ellipse.

Students will be able to draw and explain the shape of the Earth’s orbit around the Sun.

Students will recognize that the shape of the Earth’s orbit does not explain seasons.

RESOURCES: For Every Pair of Students:

A 25cm piece of string or twine

1 pencil

3 sheets of blank paper

2 push pins or thumb tacks

A stack of newspapers, the thickness of the tacks

1 ruler

For the class:

1- 40cm piece of string or twine

1 bulletin board or chart paper pad

1 piece of paper at least 14x14 inches

2 push pins or thumb tacks

1 overhead transparency of 3 ellipses and comet

1 blank overhead transparency

2 different colored transparency pens

1 hula hoop or large round embroidery hoop

Scratch paper to draw extra ellipses

SAFETY CONSIDERATIONS: Make sure to collect thumb tacks or push pins from students.

SUPLEMENTARY MATERIALS, HANDOUTS:

Seasons Lab Book Activity 4 page 9, for each student

ENGAGEMENT		Time: __5min______
What the Teacher Will Do	Hoped for Student Response
Today we are going to learn how to draw ellipses. And learn what shape is the Earth’s orbit around the sun. Draw three orbit shapes on the board, label A, B, and C.
Which drawing most correctly shows the shape of the Earth’s orbit around the Sun? Write student answers on the board. Does anyone know what an ellipse is? Which of the drawings is an ellipse?	Students choose which drawing best represents shape of Earth’s orbit.

EXPLORATION		Time: _____20min___
What the Teacher Will Do	Hoped for Student Response
Demonstrate how to draw ellipse by drawing the orbit of a comet. You will draw a couple of ellipses representing real orbits of the Earth and Pluto which both revolve around the Sun. Your goal will be to find out the shape of each orbit, and how much Earth’s orbit deviates from a perfect circle. Have students group into pairs. Pass out the materials. The strings will already be looped. The students will need two thumbtacks and either cardboard or newspapers to protect the desks. Teacher walks around the classroom and asks questions. How does the Earth’s orbit compare with Pluto’s orbit? What happens when the foci are far apart? What happens when the foci are close together? Emphasize that partners need to hold pins in place and they need to work together.	Accurate drawings of ellipses. Students should notice how the Earth’s orbit is rather circular as compared to Pluto’s. Students should also notice that when foci are very close together the orbit is close to circular like a circle which has only one focus. And when the foci are further apart the orbit is less circular and more oval.

EXPLANATION		Time: ____5min____
What the Teacher Will Do	Hoped for Student Response
Keep in mind that to compare shapes of the orbit is the goal of this exercise, not how big. What differences were found between the two ellipses that were drawn? Always remember that the Sun is fixed at only one of the foci of the ellipse. If this is true, is the Sun closer to the Earth at different times of the orbit? And does the shape of the orbit affect the seasons we experience here on Earth and how? Point to the shorter distance part of the orbit. What if I told you that in the winter the earth is here? Is the Earth closer to the sun or farther away? Is the difference significant?	Students should notice that both ellipses are somewhat circular One more circular and one more oval. Yes, because the distance is different at different sides. Yes, it is closer to the Earth at different seasons. It is closer. No

ELABORATION		Time: __5min______
What the Teacher Will Do	Hoped for Student Response
Brainstorm other possible reasons for the seasons. What is the difference between days in the summer and in the winter? In the summer, when is the hottest during a day? What is it hotter later in the day?	Length of days In the summer days are longer In the winter days are shorter Late in the afternoon Because the sun has been warming the Earth longer

EVALUATION		Time: ____10min____
What the Teacher Will Do	Hoped for Student Response
Teacher will have students review survey on the shape of Earth’s orbit around the Sun. Students will have opportunity to change their answers and explain why in their journals.
Students will also turn in ellipses worksheet.