Download Answer as a group before you watch the video

MOVEMENT IN SPACE
https://www.youtube.com/watch?v=E43-CfukEgs
Answer as a group before you watch the video:
If you dropped a feather and a bowling ball from the same height, which would hit the
ground first?
WHY?
After you watch the video:
Reevaluate your answer from above, what parts were correct? What parts were
incorrect?
What caused the result you saw the second time the objects were dropped?
WEIGHT
MASS
Weight is a measure of the pull of gravity on
Mass is the amount of matter in an object
an object.
Weight on Earth is based on the pull of gravity Mass is the same no matter where the object is
toward the center of Earth.
located as long as the object does not gain or
lose any of its matter.
Your weight would change on different
planets based on how much gravitational pull
they have
Your mass would not change if you could
travel to another planet
FORCE OF GRAVITY:
*a ______________ between all objects in the universe.
*This is influenced by …
1. the mass of the objects
2. the distance between them
Effects of Mass and Distance on Gravitational Force
A _____________ massive object has greater gravitational pull on ____________ massive
objects 
Ex. The Sun is the most massive object in the solar system and so it has the greatest pull
on objects, like planets, in the solar system
The __________________ the distance between objects the greater the gravitational pull 
Ex. The Moon has a greater effect on Earth’s tides than the Sun because it is closer to
Earth.
These two factors of gravitational force cause distinct motions between and among celestial
bodies – such as the Sun, planets and their moons
Understanding Check
Circle which planet has a greater gravitational pull on the other?
How do you know?
Which moon has a greater pull on the planet, Moon 1 or Moon 2?
Why?
100,000 km
200,000 km
Effects of Gravity on Planetary Orbits
The Sun’s gravitational pull, plus the planet’s ______________________ (Inertia means
continual forward motion), keeps the planets moving in elliptical orbits (Earth’s orbit is slightly
oval) and determines how fast they orbit.
Planets __________________ to the Sun move/orbit faster than planets farther
from the Sun because the gravitational attraction is greater.
When a planet is farther from the Sun, the gravitational attraction between them
decreases and the planet moves/orbits ____________________.
Orbits may change due to the gravitational effects from, or collisions with, other objects in the
solar system.
Understanding Check: Which planet has the fastest orbit? _________________________
Which planet has the slowest orbit? _________________________