WEIGHT A MINUTE
This lesson is designed as an innovative learning experience
which integrates video-based technology interactively in-corporating
participation. Video and hands-on activities introduce scientific
made real through re-cognition and understanding the phenomena of
force and how it impacts life on our planet. Concepts demonstrating
of Earth's gravitational force on objects are introduced and
3-2-1 CLASSROOM CONTACT
Measuring G's #122
Students will be able to:
- explain the effects of gravity;
- demonstrate how objects are accelerated by gravity at the same
- calculate effects of gra-vitational force on planets;
- discuss effects of weight-lessness on the human body.
- 1 chalkboard, chalk, eraser
- 1 weight scale (bathroom type)
- 1 styrofoam cup
- 1 sharp pencil
- 1 cup water
- 1 empty bucket
- 8 ounces vinegar
- 3 small chicken bones
- 1 small transparent container with lid
- 1 sheet notebook paper
- 1 pencil
- 1 Activity Sheet #1
- 1 Activity Sheet #2
- 1 calculator
- free fall
Hold a chalkboard eraser in the palm of your hand as you
students' attention by asking, "How will the eraser react when I invert
my hand?" Elicit response, the eraser will fall to the classroom floor.
Demonstrate the eraser falling as you invert your hand. Say, "Whenever
an object moves, it is propelled by some force. In this demonstration,
force is gravity." Write term on chalkboard, then ask students to define
and tell what they know about gravity. (A fundamental physical force
by gravitational attraction of the earth's, moon's or other planets'
for bodies at or near their surface.)
Use a styrofoam cup of water and an empty bucket to demonstrate
pull, free fall and weightlessness. The demonstration shows how a stream
of water flowing from a hole in the cup will discontinue its flow during
the descent, as you release the cup allowing it to fall into the bucket.
Procedure: Punch a small hole in the side of the cup near its bottom;
your thumb over the hole, then fill the cup with water. Ask, "What
will happen to the water in the cup if I move my thumb?" Allow time
for students to respond, then move your thumb and allow a small amount of
water to stream from the cup and fall into the bucket. Quickly,
your thumb over the hole. Ask, "If I release the cup allowing it to
free fall toward the bucket, will water flow from the hole during its
Allow students to interact as they share their beliefs. Stand on a chair
or table, which permits the cup to be dropped from a greater height, hold
it directly above the bucket, then release it. Encourage students to
why no water poured from the hole as the cup fell toward the bucket.
Write free fall, gravitational pull and weightlessness on chalkboard.
students to interact as they discuss their perception of the terms. Lead
the discussion to a conclusion that: gravitational force pulls water
the hole if the cup is motionless; and when the cup was released and
to free fall toward the bucket, water remained inside because there was
an equal amount of force exerted by gravity on the cup and the water.
Say, "Whenever astronauts orbit Earth inside a space craft, they become
weightless as they float in space because they and the craft are in a
of free fall. As the cup of water fell toward the bucket, it too was in
a state of free fall for the brief period it took to reach the
Say, "You are going to see a video that explains the
of weight and weightlessness to gravity. It also explains why objects
weight." To give students a specific responsibility while viewing say,
"Watch and be prepared to tell why you have a specific weight and a
classmate has another."
3-2-1 CLASSROOM CONTACT
Measuring G's #122
BEGIN tape immediately following opening credits; audio is,
G's." PAUSE tape at end of cartoon segment; audio is, "...and
you feel weightless." Ask, "What causes you to have weight?"
(gravity) Confirm it is the pull of gravity's invisible force that gives
weight to objects within its gravitational field. Ask, "G is used to
define a unit of force. What is a G equal to?" (the force exerted by
gravity on a body at rest; and also used to indicate the force a body is
subjected to when accelerated) Write 1 G on chalkboard. Explain: The
gravity of earth is considered to be 1 G. It is the size, mass and
of a planet that determines its gravitational pull. Write on chalkboard:
size, mass, density = gravitational pull. Ask, "Would the surface gravity
of a planet smaller in size than earth always have a surface gravity less
than 1 G?" Elicit discussion; lead to the conclusion, not necessarily;
mass and density may be much greater than earth.
Distribute a copy of Activity Sheet #1, a sheet of notebook paper, a
and a pencil to each student. Use a bathroom or other type scale to
the weight of each student. Record weight in Earth/Actual Weight space on
the Activity Sheet chart. Review information and the example to be sure
students understand the task. Allow time for completion of the activity;
discuss and have students check work for accuracy. Ask, "On which planet
did you weigh the least? The most? On which planet was your weight
to your Earth weight?" Tell students to retain the Activity Sheet.
It is needed later in the lesson.
Say, "You now know that all objects are accelerated by gravity at the
same rate. At what rate are objects on Earth accelerated by gravity?"
(1 G force) Say, "Use this information and explain why in the earlier
demonstration, water stopped flowing from the hole in the cup during its
free fall (weightless period) as it fell toward the bucket. Allow
to explain the water could not flow from the container because the 1 G
of gravity was pulling on the water and styrofoam cup at the same
Write Galileo on chalkboard. Say, "Galileo was an Italian astronomer
and physicist who lived between 1564-1642. It was Galileo who discovered
that all objects accelerate at the same rate, in equal increments of
Allow students to discuss and share their knowledge about Galileo. Ask,
"How old was Galileo at the time of his death?" Write 1564-1642
on chalkboard. Affirm Galileo was 78 when he died. Ask, "How many years
have passed since his death?" Have students subtract 1996 - 1642 =
354. Say, "No one has disputed Galileo's theory that all objects
at the same rate, in equal increments of time, in all the three hundred
fifty four years since his death." Ask, "How might you consider
his discovery the beginning of knowledge necessary to develop today's
program?" Allow students to interact; accept all explanations.
Say, "Understanding weightlessness and free fall is key to all travel
beyond Earth's atmosphere. In the next video, you are given explanations
for both. To give students a specific responsibility while viewing say,
"Watch to see an example that proves Galileo's theory true and to find
out the boys approximate weight." BEGIN tape as the boy goes
through the revolving door leading into the building's lobby.
tape as adults on the elevator exit on the Observation Deck. Allow time
for students to tell the boy's weight is approximately 62 pounds and the
Observation Deck is on the 100th floor; record statistics on
Explain the next video segment shows the boy weighing himself on the
Ask, "What do you predict happens to the boy's weight as the elevator
descends?" Allow students to make their predictions. To give students
a specific responsibility while viewing say, "Watch the video to find
out if your prediction is correct." RESUME tape. Allow students
to validate their predictions as you PAUSE tape with visual of boy
in elevator; audio is, "It works!" Ask, "Was your prediction
about the boy's weight change correct?" Allow time for students to
share information about their predictions. Instruct students to write a
brief explanation stating why the boy's weight decreased during the time
the elevator descended.
To give students a specific responsibility while viewing say, "Compare
your explanation with the video's explanation as you view the next
RESUME tape. PAUSE tape on visual of the boy and adults
the elevator. Allow time for students to compare their explanations for
the temporarily reduced weight of the boy with the video explanation. Use
this activity to evaluate whether the concept of gravity has been
by individual students. Make a note to provide individual assistance at
a later time for students who evidence the need.
Say, "Exclude outer space and think of situations that would cause
you momentary weightlessness." Accept all reasonable responses as:
underwater, bungi jumping, falling off a cliff, diving from the high
into a swimming pool, some amusement park rides, etc.; record on
Ask students to share any experience they have actually had with
weightlessness. Create a grid on the chalkboard; label it Momentary
The grid should include a number of horizontal lines which equals class
enrollment plus two or three extras. Begin at bottom and number one
the class enrollment moving up the left margin. Draw (e.g. ten) vertical
lines from top to bottom. Move left to right at bottom and label each
column" with a student shared weightlessness experience. Poll the class
to determine how many students have experienced each example of
listed on the grid. Use statistics from each tally to create either a
or Bar graph. Have students discuss the graph information
Say, "At the time you had the weight-lessness experience you contributed
toward making the graph, the sensation you felt was a free fall. Had your
free fall been scientifically measured, it would have been recorded in
of G force. In the next video, you are shown how G force is recorded."
To give students a specific responsibility while viewing say, "Watch
and be prepared to discuss the G force experienced by an object under
circumstances and G force ex-perienced during other various activities."
RESUME tape. STOP tape on visual of boy again on elevator
looking at the scale. Elicit discussion among students. Include: "What
pulls a roller coaster downhill?" (gravity) "How would you define
free fall and where did the term originate?" (a feeling or sensation
of lightness; space program/astronaut) "Under normal cir-cumstances,
how many G's do you feel?" (1 G) Encourage students to internalize
the familiar sensation of 1 G force of gravity (normal activity) as you
have them compare it to the sensation they might experience if riding in
a convertible traveling 75 MPH, skiing down a mountain or roller blading
on a sidewalk.
Students should be able to explain the weight of a person (object)
on the G force they are subjected to. Record on chalkboard, then have
discuss: 1 G = force of gravity at sea level; 0 G = no force of gravity
due to a state of weightlessness; and 2 G's = twice the force of gravity,
Explain the effects of weightlessness on the human body is a great
to scientists and astronauts. Ask students to share effects they felt on
an occasion when they rode in a roller coaster. Ask students to respond
and qualify their answer to the question, "Do you believe an astronaut's
height changes when in space?" Explain: "Some of us are slightly
taller immediately after we get out of bed in the morning." Have two
volunteers stand and demonstrate location of one another's vertebrae.
vertebrae on chalkboard. Say, "Separating and cushioning the vertebrae
is a substance called cartilage. During periods of activity the cartilage
becomes more tightly compressed between the vertebrae. When a person is
at rest, weight is shifted allowing the cartilage to expand, thus causing
the individual to appear slightly taller." Suggest students have someone
measure their height before going to bed and immediately upon arising the
next morning. On the appropriate day(s), provide time for students who
in the experiment to share results.
Write on chalkboard: Which mineral does the human body lose during space
travel? What happens to muscle tone while traveling in space? To give
a specific responsibility while viewing call attention to the questions,
then say, "Watch the next video and be prepared to answer the questions."
BEGIN tape with visual of a male astronaut in a space craft
as he types. STOP tape after female narrator says, "...but they
don't stop it completely." Video is an astronaut lifting weights for
body tone. Engage students in interaction as they discuss calcium is the
mineral lost by the human body in space; and an individual's muscle tone
is reduced during space travel.
Pre-prepare the following one week prior to presenting the lesson (for
observation of result) or prepare in view of students at this point in
and encourage observation throughout the week. DEMONSTRATION: Place three
small chicken bones in a transparent container, cover bones with vinegar
and replace the container's lid. One week is necessary for the vinegar to
extract calcium rendering the chicken bones rubbery and easily bent.
bones; allow students to experience the characteristics of a bone that
had its calcium extracted. Use this opportunity to emphasize need for
a well balanced diet which includes all nutrients, vitamins and minerals
necessary to promote growth and maintain health.
Ask, "What will happen to an astronaut's bones if a significant amount
of calcium is lost?" Elicit discussion drawing conclusion that loss
of calcium will cause the bones to bend and break easily. Relate
to the condition (or anticipated condition) of the chicken bones
Emphasize that great care is taken in the development of a routine
program to be followed and special diet to be consumed whenever humans
Plan a field trip to an amusement park. Construct a G Meter
as shown on the video, then use it to measure the G force on selected
There are twenty-eight Challenger Space Centers throughout the United
If one is located reasonably convenient to your community, plan a field
trip. Students will have an opportunity to participate in a simulated
mission and learn the jobs of astronauts and mission control
Invite a professional scuba diver to visit your classroom if you live in
a community where individuals in this profession are located. Ask them to
discuss how G force affects their work, how it can impose limitations on
their jobs and why knowledge of G force is critical to safety on the job.
If professional scuba divers are not an option, Police Departments in
large cities have a Tactical Force which includes officers with scuba
Distribute a copy of Activity Sheet #2 to each student. Instruct them to
use their "actual weight" figure from Activity Sheet #1 and create
a Bar or Line Graph. The graph will show the individual's weight on each
planet in the Solar System. Display the graphs in your classroom.
Have students select various objects and drop them from a height. Prior
to the drop, have students predict which object(s) will reach the ground
The center of gravity is the point where an object can be balanced. Use
a coat hanger, place a fork on a potato at different locations, etc., and
have students experiment with the concept.
If you have an ice skater in your class or school, ask them to discuss
importance of being knowledgeable about center of gravity and how G force
can impact per-formance in this sport.
Study muscle tone and the effects of exercise on the body. Have students
design a program of exercise that could be beneficial to astronauts.
Read: The Day We Walked on the Moon and Apollo 13 Have students use
and compose newspaper headlines they believe could be applicable to space
exploration in the year 2005.
Master Teachers: Jaci Stewart and Anna Sedoris
Lesson Plan Database
Thirteen Ed Online