Warm- upTrue or false?

1. If the earth stopped spinning we would float into space.2. There is no gravity on the moon.3. NASA have an anti-gravity room where gravity can be turned off

and people can float.4. It is possible to shield the force of gravity by using lead or other

materials.5. Isaac Newton discovered gravity.6. Nottingham Forest won the Champions league in 1979 and 1980.7. You have no mass in space.8. There is no gravity in space because you are far from the earth.9. Weight is measured in kilograms.10. There is no gravity in space because space is a vacuum.11. If we could suck all the air out of the classroom, we would float

around.

All false!• If the earth stopped spinning we would float into space.• There is no gravity on the moon.• NASA have an anti-gravity room where gravity can be turned off

and people can float.• It is possible to shield the force of gravity by using lead or other

materials.• Isaac Newton discovered gravity.• Nottingham Forest won the Champions league in 1979 and 1980.• You have no mass in space.• There is no gravity in space because you are far from the earth.• Weight is measured in kilograms.• There is no gravity in space because space is a vacuum.• If we could suck all the air out of the classroom, we would float

around.

Only this one is true!

http://www.youtube.com/watch?v=puLZe-IKbnY

http://www.youtube.com/watch?v=puLZe-IKbnY

http://www.youtube.com/watch?v=aT58uS8VK6ghttp://www.youtube.com/watch?v=_mCC-68LyZM

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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 planets5.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 gravity7.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.

Do astronauts

actuallylose weight

while in space?

Earth is exerting a noticeable force on

these people.

Gravity is a Basic Force in the universe. It affects all objects

in the universe.

Gravity is an attractive force between two objects.

So… what is gravity?

Why does the cereal and milk fall downward?

The law of gravitation states that any two

objects exert an attractive force on each

other.

http://www.youtube.com/watch?v=_mCC-68LyZM

Gravity is related to two things.

Watch this video and listen for the 2 things that gravity relies upon.

http://www.youtube.com/watch?v=aT58uS8VK6g

Gravity is related to two things:

1. mass of the objects2. the distance between the

objects

GravityThe size of the force depends on the mass of the objects. The bigger they are, the bigger the force!

Small attractive force

Bigger attractive force

Mass

Mass is a measure of the amount of material an object is made of. It is measured in kilograms.

Mass and weight

Mass is a measure of the amount of material an object is made of. It is measured in kilograms.

Weight is the force of gravity on an object. It is measured in Newtons.

Gravity

The size of the force also depends on 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.

The larger an object is, the more gravity it creates.

Explain what is happening in this animation?

http://www.splung.com/content/sid/2/page/gravitation

What is going on in this animation?

The attractive force of gravity increases if the mass of the objects

increase.

The attractive force of gravity increases if the distance between

the objects decreases.

To Sum It All Up !

Mass is the amount of matter within an object.

Weight is a measurement of gravitational force upon the mass of the object.

We often use the words “mass and weight” interchangeably. But there is a

difference between the two words.

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.

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 are near Pluto and put a scale underneath you. Is the scale weightless?

Is the scale mass-less?

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?

Location Gravity Factor

Earth 1

Earth's moon 0.17

Venus 0.90

Mars 0.38

Mercury 0.38

Jupiter 2.36

Saturn 0.92

Uranus 0.89

Neptune 1.13

Pluto .007

What would be the formula to calculate your weight?

Weight = mass x gravity factor

Let’s do one together.Now you help me one.

You do the other calculations.

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 mass-less.

Let’s look at some characteristics of planets

You can also look on your worksheet

Radi

us in

met

ers

Form and write a hypothesis about what you think is most important in

determining a planet's gravitational strength?

So which planet characteristics cause a planet to have more or less gravity?

Consider the variables we just looked at.

Go to the section called “investigating your hypothesis”

Never assume, we must investigate!

We will find out how much you weigh on other planets.

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 asF = m x g

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 My calculations & support of my hypothesis

Diameter of Jupiter is 88,729 miles

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.

Pair up with the person on your right. Odd rows pair up with even

rows. Complete your exit ticket activity.

Quickly !!!!

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 1.725Ursa Major with gravity factor of 6.063

http://teacher.scholastic.com/activities/explorations/space/level1/interactive.htm

Moon olympics

http://www.exploratorium.edu/ronh/weight/

To find your weight on different planets

Let’s check your work