Standard –
CLE 3202.4.1 Explore the difference between mass
and weight.
CLE 3202.4.2 Relate gravitational force to mass.
CLE 3202.Math.2 Utilize appropriate mathematical
equations and processes to solve basic physics
problems.
CLE 3202.Inq.1 Recognize that science is a progressive
endeavor that reevaluates and extends what is
already accepted.
Objective: Today you will….
1.Describe gravity.
2.Explain the relationship between weight and mass.
3.Compare and contrast planet characteristics to derive what variables
influence a planet's gravitational strength.
4.Discover how much you weigh on various planets
5.Investigate your hypothesis by calculating your weight on each planet.
Prove or disprove your hypothesis about the causes of a planet's
gravitational strength
6.write a paragraph that explains what characteristics cause a planet to
have more or less gravity
7.Predict what you would weigh on newly discovered planets.
Bell ringer:
1. On Earth how could you judge up from down?
2. Predict the weight if a scale floated by an astronaut
in space and he stood on it.
Earth is
exerting a
noticeable
force on
these
people.
Do
astronauts
actually
lose weight
while in
space?
Gravity is a Basic Force in
the universe. It affects all
objects in the universe.
So… what is gravity?
Why does the cereal
and milk fall
downward?
Gravity is an attractive force
between two objects.
The law of gravitation
states that any two
objects exert an
attractive force on
each other.
Gravity is related to two things.
Watch this video and listen for the
2 things that gravity relies upon.
Gravity is related to two things:
1. mass of the objects
2. the distance between the
objects
How do these 2 things affect the
amount of gravity?
Let’s look at 2 animations to
answer this question.
Explain what is happening in this animation?
The larger an object is, the more gravity it
creates.
What is going on in this animation?
http://www.splung.com/content/sid/2/page/g
ravitation
The attractive force of gravity
increases if the distance between
the objects decreases.
To Sum It All Up !
The attractive force of gravity
increases if the mass of the objects
increase.
We often use the words “mass and
weight” interchangeably. But there is a
difference between the two words.
Mass is the amount of matter within an
object.
Weight is a measurement of gravitational
force upon the mass of the object.
Scales measure the force of attraction
between you and the Earth. The more mass
you have, the more gravitational force on you
and the more you weigh.
We can also use a scale to measure the
force of gravity on us at various
distances from the Earth’s core.
For example, your
weight would be
0.2% less on the top
of Mt. Everest.
Why do you weigh less?
Predict what happens to your mass?
Theorize how much your weight changes
as you move across our solar system?
What does this weight change depend
upon?
You are near Pluto and put a scale
underneath you. What would the scale
read?
The scale would read
zero, you weigh zero.
You are weightless.
You are not massless.
You are near Pluto and put a scale
underneath you. Is the scale weightless?
Is the scale mass-less?
Absolutely not. If you grabbed the
scale and tried to shake it, you would
have to push it to get it going and
pull it to get it to stop. It still has
inertia, and hence mass, yet it has no
weight.
You can also look on your worksheet
Let’s look at some characteristics of planets
80,000,000
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Series7
Neptune
Pluto
60,000,000
50,000,000
40,000,000
30,000,000
20,000,000
10,000,000
Radius in meters
70,000,000
0
1
So which planet characteristics cause a
planet to have more or less gravity?
Consider the variables we just looked
at.
Form and write a hypothesis about what
you think is most important in
determining a planet's gravitational
strength?
Never assume, we
must investigate!
We will find out how
much you weigh on
other planets.
Go to the section called
“investigating your hypothesis”
Location
Earth
Gravity Factor
1
What would be the
formula to calculate
your weight?
Earth's moon
0.17
Venus
0.90
Let’s do one together.
Mars
0.38
Now you help me one.
Mercury
0.38
Jupiter
2.36
Saturn
0.92
Uranus
0.89
Neptune
1.13
Pluto
.007
You do the other calculations.
Weight = mass x gravity factor
Go to the section “Analyze your data”
Where do you weigh the most?
I weigh the most on Jupiter. I weigh
401 pounds on Jupiter.
I weigh the least on Pluto with a
weight of 1.19 pounds.
Is weight a force?
We can rewrite this formula as
F=mxg
This formula will lead into Newton’s
second law of motion, which we will
discuss later.
Now, which planetary property seems to
cause you to weigh more or less on other
planets?
Use your calculations and the Solar System Data Table
to support or disprove the proposed hypotheses.
Why do you agree or disagree? Give examples from
your data.
For example:
Planetary property
Diameter of Jupiter is 88,729
miles
My calculations & support of
my hypothesis
My calculations show that I weigh
401 pounds on Jupiter. Since I weigh
the most on this planet, I think that
the force of gravity (weight) is high on
this planet because of the diameter.
Now that we have analyzed
our data, let’s summarize our
findings.
Quickly !!!!
Pair up with the person on your
right. Odd rows pair up with even
rows. Complete your exit ticket
activity.
Write a brief paragraph that explains in detail.
•Which properties cause a planet to have
more or less gravity? Why?
•Which properties do not impact gravity?
Why?
•How does gravity affect objects on the
planet?
Use what you have learned to predict how
much would you weigh on some far away
stars?
Andromeda with gravity factor of 1.725
Ursa Major with gravity factor of 6.063
Moon olympics
http://teacher.scholastic.com/activities/explor
ations/space/level1/interactive.htm
Let’s check your work
To find your weight on different planets
http://www.exploratorium.edu/ronh/weight/