MACHINES
A seesaw is an example of which simple machine?
A lever
What is gravity?
A force that pulls objects toward the center of the Earth
What keeps force keeps the Moon in orbit around the Earth?
Gravity
What causes tides on Earth?
The Moon’s gravitational pull.
What causes day and night on Earth?
The Earth’s rotation on its axis
A wheelchair ramp is an example of which simple machine?
An inclined plane
Does gravity act only on Earth?
No, it acts on everything in the universe with mass
What do we call the path an object takes as it moves around another object in space?
An orbit
Where are there two high tides each day?
One on the side facing the Moon and one on the opposite side.
Why do we have different seasons on Earth?
Because the Earth is tilted on its axis as it orbits the Sun
An axe is an example of which simple machine?
A wedge
Which has more gravity: the Earth or the Moon? Why?
Earth, because it has more mass
What is orbital velocity?
The speed needed to stay in orbit.
What are spring tides?
Very high tides when the Earth, Moon, and Sun are aligned.
How long does it take for Earth to orbit the Sun once?
1 year (365.25 days)
A flagpole that uses a rope and wheel is an example of which simple machine?
A pulley
What happens to gravity as you move further from Earth?
It gets weaker
What is escape velocity?
The speed needed to break free of a planet’s gravity.
What are neap tides?
Weaker tides when the Sun and Moon are at right angles to the Earth.
What causes a solar eclipse?
The Moon passes between the Earth and the Sun, blocking the Sun’s light.
A screwdriver that twists screws is an example of which simple machine?
A wheel and axle
Why do a bowling ball and feather fall at the same rate in a vacuum?
No air resistance; gravity affects all masses equally in free fall
The gravity and inertia forces acting on an object like the Moon must be ________ for it to stay in orbit around the Earth.
Balanced
Why are there two high tides on Earth each day, even though the Moon only pulls in one direction?
One high tide is caused by the Moon’s gravitational pull on the water facing it.
The second high tide happens on the opposite side because the Earth is pulled slightly away from the water, creating another bulge.
What is the difference between a star and a planet?
A star produces its own light and heat through nuclear reactions, while a planet reflects light and does not produce its own light.