Download Station #3: Make a Refracting Telescope

Station #1: The Reason for the Seasons
The Earth turns on an imaginary axle called an axis. The axis of the earth is tilted about
23 ½ degrees. It takes the Earth 24 hours to make one complete revolution. The Earth is
also revolving around the sun. At different times of the year different parts of the Earth’s
surface face the sun for longer or for shorter periods of time. Most parts of the world
have four such periods or seasons. They are spring, summer, autumn and winter. During
the summer season, there is more daylight. In winter, there is less. In spring and autumn,
the hours of light and dark are about the same. Some parts of the world have only two
seasons: rainy and dry.
If the Earth did not tilt on its axis, there would be no seasons. Every day would have 12
hours of light and 12 hours of dark. But since the Earth’s axis is at an angle to its orbital
plane, we have summer and winter, long days and short. When the North Pole tips
toward the Sun, the Northern Hemisphere has summer warmth. When the South Pole tips
toward the Sun, Australia has summer and North America has winter. As the Earth
swings around the Sun different parts of its surface are exposed to sunlight for different
lengths of time each day.
For this station, you can place the black presentation boards in a semi-circle around the
season display and place a black foam poster board on top to block out the light. You can
also just set up the season display on the table in front of the students. Have students
stand/sit near the table and observe the model of the sun and earth in each of the four
seasons. It is probably better to divide the group in half so that students are able to see
the model better if they are standing around the black display boards. Have students
locate the North Pole, the Northern Hemisphere and Georgia (red star).
Help students answer the questions on their sheets.
How long does it take Earth to complete one revolution around the sun? 365 days
Is Earth’s axis of rotation straight up and down OR tilted? Tilted
Have students locate the season of their birthday and describe the tilt of the Earth during
the season of their birthday. Is the Northern Hemisphere tilted toward the sun, away
from the sun or neither way?
Station #2: Make a Refracting Telescope
Astronomers study space with optical telescopes. These telescopes capture light
streaming toward Earth from every corner of the universe. Today we are going to make a
simple Refracting Telescope. A Refracting Telescope is a telescope that uses a convex
objective lens to focus light directly into an eyepiece lens which then magnifies an image.
Hand each student one small diameter cardboard tube, one large diameter cardboard tube,
one thin (larger) lens that is inside a red cap, and one thicker (smaller) lens protected
inside a circular piece of gray foam. Have each student place their larger lens with the
red cap on one end of the larger diameter cardboard tube. Next, have students place their
smaller lens with the gray foam circle into one end of the smaller diameter cardboard
tube.
Have students carefully slide the open end of the smaller diameter cardboard tube into the
open end of the larger diameter cardboard tube. Students should hold their telescope up
and look through the end opposite the red end. Have students focus on a far off object in
the room (maybe one of the planets hanging from the ceiling) by sliding the small tube in
and out of the larger tube until the image they are viewing is in focus. If they have
trouble seeing an image take them outside and let them focus on an object in a tree
behind the portables, a birdhouse or some brush in the woods.
Ask the students: How do objects appear through the telescope? Objects will appear
upside down and larger, because of the manner in which light traveling through the
lens is bent. Ask students which lens they were looking through when the objects
appeared larger? The smaller (thicker) lens Ask students if they were to look through a
telescope to observe the night sky which is the better lens to look through. They should
look through a thicker (convex) lens for larger images.
Note: If it is hard for some students to understand the difference in lenses, show them
using the two lenses provided that when placed over printed words a concave lens will
not change the size of an object, while a convex lens will make an object larger.
Ask students to place their telescopes on the table and answer the questions on their
sheets. Provide assistance as needed. After the sheets are completed you can read the
information below to them and show them pictures of different refracting and reflecting
telescopes shown in the book provided.
Additional Information about Telescopes
Another type of optical telescope is a Reflecting Telescope. In this type of telescope
light strikes a concave primary mirror at the back of the reflecting telescope and bounces
back up the tube to a smaller flat angled secondary mirror, then to an eyepiece. Bigger
telescopes used today are reflecting telescopes. (For example, the Hubble Space
Telescope)
Station #3: Model of the Solar System
Explain to the students that you will be helping them to make a model of the solar system
similar to the one you have for display. Divide the group in half and use both tables so
there is plenty of room for student to work. Give each pair of students one long strip of
black paper, a glue stick and a yardstick. In each rotation, students will make four
models. Collect them and give them to the teacher to use when the class studies Space.
Have students glue the half sun to the edge of the black strip of paper. Ask students to
place the black paper on the table lengthwise and place the yard stick on top of the paper
with the edge resting on the edge of the yellow sun.
Using the chart below students should place stickers or die cuts representing the planets
in order the distance from the sun listed on the chart under the heading Scale Distance
from Sun (inches). Students may make a mark on the black paper with there pencil if
they like before placing the sticker or die cut. Here is a description of the planet and the
die cut or sticker used to represent each:
Mercury – yellow ¼” sticker
Venus – green ¼” sticker
Earth – blue ¼” sticker
Mars – red ¼” sticker
Jupiter – orange large circle
Saturn – red planet die cut
Uranus – green circle die cut
Neptune – blue circle die cut
Pluto – make a small dot with a gel pen
½ inch from sun
¾ inch from sun
1 inch from sun
2 inches from sun
5 inches from sun
10 inches from sun
19 inches from sun
30 inches from sun
39 inches from sun
Remind students of the memory trick to remember the order of planets: My Very Eager
Mother Just Saved Us Nine Pennies
If there is enough time students can label the planets and the asteroid belt with the gel
markers.
½
Planet’s
Diameter
(rounded
to nearest
1000 km)
5000
Approximate
Scale Size of
Planet
Diameter
(inches)
¼
0.7
¾
12000
½
150 million
1
1
13000
½
Mars
228 million
2
2
7000
¼
Jupiter
778 million
5
5
143000
6
Saturn
1429
million
2871
million
4500
million
5900
million
10
10
121000
5
19
19
51000
2
30
30
50000
2
39
39
2000
1/8
Planet
Average
Distance
from Sun
(km)
Distance
from Sun in
Astronomic
al Units
Scale
Distance
from Sun
(inches)
Mercury
58 million
0.4
Venus
108 million
Earth
Uranus
Neptune
Pluto