Duration
of Activity:
40
minutes.
Student
Prerequisites:
Students should have prior exposure to the topics of the
Sun and the Moon through reading and class discussions and
have a basic understanding of the relative locations of the
Sun, Earth and Moon. They should also have practiced measuring
the size and distance of objects.
Materials:
 Any
largeformat Big Book
 Rulers
 Balls
measuring 3/4inch and 1 1/2inch (a pingpong ball works
well for the large ball)
 Pencils
 Work
sheet to record observations
 Masking
tape
Teacher
Background Information:
 The
Sun is approximately 93 million miles from Earth. A car
going 60 miles an hour would take about 177 years to reach
the Sun from Earth.
 The
Moon is much closer to the Earth. The distance is less than
240,000 miles. A car going 60 miles an hour would take about
5.5 months to reach the Moon from Earth.
Teacher
Preparation:
Allow
time to locate spheres of various sizes and to print out student
work sheets.
Work
Sheets:
"Little
Moon Giant Sun" Work Sheets 


Need
help? 
View Completed Student Work Sheets 



Objectives:
Students
will learn that
 Distance
affects how we perceive size.
 The
further an object is from us, the smaller it looks to us.
 The
Sun and Moon have different sizes, but can appear to be
the same size because of differing distances from the Earth.
Grade
Level:
Grades 13
Procedure:
Procedure:
Part One
Whole
Class Introduction
 Distribute
rulers to students.
 Ask
for a student volunteer to hold up a big book in front of
the class.
 Select
three studentsone at about 3’, 10’ and 20’
from the front of the classroom.
 Ask
each student for the height measurement of the book. Explain
that to measure, students should hold ruler vertically at
arm's length and close one eye.
 Write
measurements on the board.
 Ask
students why they think the big book looks so small. Ask
why it looks even smaller from the back of the room.
 Ask
if they can think of other things that sometimes look small
but are really big.
 Explain
that they will do an experiment and try to figure out why
big things can look small to us.
 Explain
that they will get a big ball to represent the Sun, a small
ball to represent the Moon, and they will be representing
the Earth in this activity.
Procedure:
Part Two
Handson
Group Activity
 Tape
a 4inch length of masking tape parallel to the edge of
the table, creating a slightly rough surface to keep balls
from rolling off the table.
 Distribute
two balls and work sheet to students.
 Have
students set the two balls sidebyside on the tape.
 Ask
students to kneel down at eyelevel with the table surface
and look at the balls with one eye closed.
 Ask
them to predict how many inches they will move the big ball
toward the middle of the table in order for it to appear
the same size as the small ball. Students record predictions
on work sheets.
 Explain
to students that they will check their predictions by doing
an experiment. Remind them that the big ball is like the
Sun, the small ball is like the Moon, and they are the Earth.
 Ask
students to again kneel down at eyelevel with the table
surface and look at the balls with one eye closed. Compare
the sizes of the balls. Ask students which looks bigger.
 Keep
the small moon ball at the table edge and ask students to
move the big Sun ball until it looks the same size as the
small Moon ball.
 Measure
the distance moved and record on work sheet.
 If
working in pairs or groups, have students alternate roles
as they do this activity so that each student gets a chance
to move the balls, measure, and record the distance.
 Complete
the work sheet.
Wholeclass
discussion:
 What
did you notice as you moved the ball away from you?
 How
did you make the balls look the same size?
 What
happened during your experiment if you moved the big ball
away from you and then rolled the small ball in front of
the big ball?
 Explain
that this is what happens during a solar eclipse when the
small Moon moves in front of the large Sun and blocks the
sunlight from viewers on Earth. Explain that the Sun is
very large, but looks small to use because it is so far
from the Earth (approximately 93 million miles). The Moon,
while much smaller than the Sun, can look to be the same
size as the Sun because it is so much closer to us (less
than 240,000 miles).
Assessment:
Use
the "The Little Moon" work sheet to assess your
students’ work.
Bibliography:
See
related books and websites.
