What is gravity?
What do we call the force that pulls things toward Earth?
gravity
Name one everyday example of gravity at work
any answer
Four identical rockets are carrying different amounts of cargo into space.
Rocket A carries 25,000 kg
Rocket B carries 150,000 kg
Rocket C carries 2,000 kg
Rocket D carries 63,000 kg
Arrange the rockets in order from the one that requires the least amount of force to launch to the one that requires the greatest amount of force. Explain how the mass of each rocket's cargo affects the force needed for launch.
Rocket C, Rocket A, Rocket D, Rocket B. Rockets carrying heavier cargo need more force to launch because they have more mass.
Which are true statements about gravity?
a) gravity holds our solar system in orbit
b) gravity acts on all objects
c) gravity is a contact force
d) gravity cannot be overcome
a) gravity holds our solar system in orbit
b) gravity acts on all objects
Who is the scientist famous for describing gravity after watching an apple fall?
Sir Isaac Newton.
How do we know an object is experiencing gravity?
We know an object is experiencing gravity because it falls toward the ground when dropped. Even if an object isn't falling, gravity is still pulling on it.
What happens to a ball when you throw it straight up?
It rises, slows, stops, and then falls back down because gravity pulls it down.
Rene and Gustavo look for objects that have overcome the force of gravity. Which objects could they identify? Select three answer choices.
a bee that is flying
a falling leaf
an airplane that is taking off
a boat floating on a lake
a hot air balloon in the sky
a bee that is flying
a hot air balloon in the sky
an airplane that is taking off
Imagine you travel to a planet that is less massive than Earth. Compared to Earth, how much force would it take for you to jump off the ground?
a) more force
b) zero force
c) less force but not zero force
d) the same amount of force
c) less force but not zero force
Which scientist later changed our idea of gravity by describing it as the bending of space and time?
Albert Einstein
Fill in the blank: On Earth, gravity pulls objects toward the _______
Earth or Center of Earth
If you drop a paperclip and a sheet of paper at the same time from the same height, which will usually hit the ground first and why?
The paperclip usually hits first because air resistance slows the paper more; gravity pulls both down.
Which object would require the greatest force to overcome Earth’s gravitational pull?
a) a hot air balloon with passengers
b) a rocket carrying astronauts
c) a toy rocket
d) a hummingbird
b) a rocket carrying astronauts
Think of a super rocket that could travel and visit other places in space. The gravity of which place would be most difficult for the rocket to overcome on its return?
a) the sun
b) Earth's moon, which has much less mass than Earth
c) Mars, a planet about the size of Earth
d) the International Space Station, now in orbit around Earth
a) the sun
Describe how you could use a ramp and a toy car to show gravity’s effect.
Let the toy car go down the ramp and observe that gravity pulls it down the slope, making it move faster.
Why does a dropped pencil fall to the floor instead of floating?
Because gravity pulls the pencil toward Earth.
A baseball player hits a ball. At what point is gravity pulling on the ball?
a) when the ball is rising
b) when the ball is falling
c) when the ball is at its highest point
d) at all times
at all times
Which animal must use the greatest force to lift off the ground?
a) a mouse, which is a small animal
b) a frog, which jumps most often
c) a rabbit, which is a fast animal
d) a jaguar, which is a heavy animal
d) a jaguar, which is a heavy animal
Why is your weight greater on Earth than in space?
You weigh more on Earth because Earth's gravity pulls on you more strongly than it does when you are far away in space. The weaker the pull of gravity, the less you weigh.
Melissa fills three paper bags with different materials: sand, gravel, and rocks. Each bag has a different mass. She drops each bag from the same height at the same time and observes that they all hit the ground at approximately the same time.
What conclusion can Melissa make about how an object's mass affects the rate at which it falls?
An object's mass does not affect how fast it falls. Heavy and light objects fall at the same rate when air resistance doesn't slow them down.
Is gravity a contact force or a noncontact force? Describe an example that supports your answer.
Gravity is a noncontact force because it can pull objects toward each other without them touching.
For example, when I drop a ball, Earth's gravity pulls it toward the ground even though the Earth isn't touching the ball while it falls.
Diane and Sami investigate gravity on a playground. Which of their observations shows that a ball has gone against the force of gravity?
a) A basketball is at rest on the ground.
b) A rubber ball is falling to the ground.
c) A baseball rises in the air when thrown.
d) A soccer ball is rolling down a hill.
c) A baseball rises in the air when thrown.
Four planets of the same size are located at different distances from the Sun. Which planet would experience the strongest gravitational pull from the Sun?
The planet closest to the Sun would experience the strongest gravitational pull because gravity is stronger when objects are closer together.
Explain in one or two sentences how gravity on the Moon is different from gravity on Earth.
The Moon’s gravity is weaker than Earth’s, so things weigh less and jump higher there.
Maya ties a small toy car to a helium balloon. She holds the balloon and lets it go. The balloon lifts the toy a little, but the toy does not float all the way to the ceiling. Maya then adds one more balloon and lets go again. This time the toy floats up to the ceiling.
Explain why the toy car could not float to the ceiling with one balloon but did float to the ceiling with two balloons.
With one balloon, the balloon’s lift was not strong enough to beat gravity pulling the toy car down, so the toy only rose a little. With two balloons, the total lift was stronger than gravity, so the toy floated all the way to the ceiling because it became lighter than the pull of gravity.