National Aeronautics and Space Administration
Earth, Earth’s Moon and Mars Balloons
Teacher Guide
Brief Lesson Overview:
For this activity students will construct a balloon scale model to understand the relative sizes
of the Earth, Earth’s Moon and Mars in relation to each other and their relative distance to
each other at this scale.
Vocabulary:
Model
Scale
Relative distance
Relative size
Goal:
In this investigation, students will use a hands-on, approach to understanding the scale and
size of the Moon and Mars in relationship to distance from Earth.
Objectives – Students Will:
1.
Make predictions regarding the relative size and distance of the Earth, Earth’s
Moon and Mars.
2.
Construct a model to compare and contrast the size of the Earth, Earth’s Moon and
Mars.
3.
Construct a model to illustrate the relative distance of the Earth, Earth’s Moon and
Mars.
Grade Level:
K-4
Additional Discipline:
Math
Estimated Time Required:
One 45-minute session
Credits: © 2011 Arizona State University Mars Education Program. This material may be
freely distributed for non-commercial use only.
©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
Relevant Standards and Skills:
1. National Science Education Standards (NSES)
a. Content Standard A: Science as Inquiry
i. Abilities Necessary to do Scientific Inquiry
b. Content Standard B: Physical Science
i. Position and Motion of an Object
c. Content Standard D: Earth and Space Science
i. Objects in the Sky
2. National Council of Teachers of Mathematics (NCTM)
a. Number Properties and Operations
i. Number Sense
ii. Estimation
iii. Number Operations
b. Geometry
i. Analysis
3. 21st Century Skills (Science and Math)
a. Critical Thinking and Systems Thinking
b. Communication
©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
Materials/Equipment (for a class of 30 students):
1. 30 balloons of three different colors
(e.g., Blue – Earth, Red – Mars, White – Earth’s Moon)
2. 10 - Tape Measures (or meter sticks and a piece of string)
3. Student Sheet
Essential Question: What is the estimated difference in size between the Earth, Earth’s
Moon, and Mars?
5E Application:
1. Engage:
a. Using the Student Sheet, ask the students to make a prediction using a drawing
of the Earth, Earth’s Moon, and Mars showing what they think the sizes are in
relationship to each other.
b. Look at the image of Earth and Earth’s Moon from the Mars perspective
(http://hirise.lpl.arizona.edu/earthmoon.php) from an image taken from satellite
orbiting Mars (correct term). Discuss the size of the Earth and Earth’s Moon in
relationship to each other and from representations in books, charts and other
materials. Does it look like the Earth and Earth’s Moon are the same size?
c. Look at the image of Earth from the surface of Mars.
(http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a/11-ml-02-earthA067R1_br.jpg).
2. Explore:
a. Discuss how models are used to represent ideas or objects. Point out that
scientists and engineers create models to understand an idea or object. Today,
we will be making a model of the Earth, Earth’s Moon, and Mars to represent
their sizes and distances to scale.
b. Distribute blue balloons to 1/3 of the class, red balloons to 1/3, and white
balloons to the final 1/3. Explain that the three balloons represent the Earth
(blue), Moon (white) and Mars (red).
c. Group students in groups of 3, each with a different color balloon.
d. Ask the students with the blue balloon to blow their balloons up until it is 63
centimeters in circumference. You may need to demonstrate for the students
how to measure the circumference using a tape measure or a piece of string
and a meter stick.
e. Once the balloon is the appropriate circumference, ask the students to tie off
the balloon. This balloon will represent Earth.
f. Ask the students to fill in the Relative Size and Distance Sheet with the
circumference of Earth.
g. Students will now predict the relative circumferences of Earth’s Moon and Mars
based on the size of Earth and record that circumference prediction on the
Relative Size and Distance Sheet Balloon Circumference Prediction column.
©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
h. Explain to students that the scale for this model is 63,800,000 times smaller
than the real thing. Ask students to multiply the balloon circumference (63 cm)
X 63,800,000 (scale factor) to find the actual diameter of Earth (4,019,400,000
cm or 40,194 km).
i. To find the Actual Balloon Circumferences for Earth’s Moon and Mars, the
circumferences have been provided for both. The students will need to divide
these by 63,800,000. They should find the Moon is 17cm and Mars is 33cm.
Differentiation Alert For Older Students:
Students may then convert cm to km
j.
Students should now inflate Earth’s Moon and Mars balloon and tie them off.
3. Explain:
a. Discuss the idea of scale with students. Point out that it is obvious that the
planets and moons are not as small as the balloons, but because we calculated
them using a scale, the sizes represent the bodies in relationship to each other.
Therefore, The Earth can be estimated as twice as big as Mars, and 4 X bigger
than Earth’s Moon.
4. Elaborate:
a. Ask students to now make a prediction regarding the relative distances between
Earth, Earth’s Moon, and Mars.
a. They should stand as a group and arrange themselves based on their belief of
the relative distance and measure these distances. These measurements will
represent their prediction to be completed on the Relative Size and Distance
Sheet.
b. Student will use their new understanding of scale to calculate the relative
distances of the Earth, Moon, and Mars. They will continue to use the
63,800,000-scale model.
c. Once students have calculated the scaled differences, ask them to begin
arranging themselves into the appropriate distances.
d. Eventually a student will say they need to step out of the room to get to Mars.
This is a great time to mention, the distance to Mars is so great, that if we were
to place it correctly according to this scale, it would actually be ¾ of a mile away
(provide a visual cue the students may be familiar with that is within ¾ of a mile
of the school as a frame of reference about how far that distance really is.
e. Discuss with the students the amount of time it would take us to travel to the
Moon and Mars. Typically, it takes 2 - 3 days to reach the Moon using a rocketpowered vessel, while it would take approximately 9-11 months to reach Mars
with robotic spacecraft.
©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
Differentiation Alert: For older students:
Ask student to convert cm to km and/or use scientific notation for the planet distances.
5. Evaluate:
a. Students should complete the Student Evaluation Sheet.
Extensions:
Explore the relative size and distance of the moons of Mars or other planets in the solar
system.
©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
Earth, Earth’s Moon and Mars Balloons
Student Sheet
Essential Question: What is the estimated difference in size between the Earth, Earth’s
Moon, and Mars?
Prediction: Make a drawing of your prediction. What do you think the differences are
between the sizes of the Earth, Earth’s Moon, and Mars?
Explain why you think this is true.
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©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
Relative Size and Distance Sheet
Planet/Moon
Circumference (cm)
Earth
Earth’s Moon
Balloon
Circumference
Prediction (cm)
Actual Balloon
Circumference (cm)
63
63
Balloon Distance
Prediction (cm)
Actual Balloon
Distance (cm)
1,091,500,000
Mars
2,133,300,000
Planet/Moon
Distance (cm)
Earth to Earth’ Moon
38,400,000,000
Earth to Mars
7,800,000,000,000
Show your work:
©ASU Mars Education Program http://marsed.asu.edu/ National Aeronautics and Space Administration
Earth, Moon, Mars Balloons
Student Evaluation Sheet
What did you find the most surprising during this investigation?
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Why did we use a scale to create our model of Earth, Earth’s Moon and Mars?
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Give an example of a type of activity that scientists would use a planetary scale model?
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Revisit your original prediction. What did you not understand that caused your prediction to
be not supported?
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©ASU Mars Education Program http://marsed.asu.edu/