8.3 - Gravity, tides and orbits - Archive Flashcards
What is gravity?
A force that is able to push and pull things around without contact with the object.
What are gravitational fields?
The force field that exists in the space around every mass or group of masses.
What is matter?
Matter is the stuff that everything is made up of, and matter has mass.
What is the effect of mass?
Gravity is caused by mass and the bigger the mass, the stronger the gravitational pull.
What is an example of a very weak source of gravity?
Pens, cars, buildings, people, and chairs.
What is an example of a strong source of gravity?
Stars, Moons, and Planets such as the Earth.
What is the effect of distance?
The gravitational fields around Planets, Moons, and stars rapidly weaken as you move away from them.
How can the effect of distance be noticed?
If we were standing on the top of Mt Everest, the difference is a little too small for us to be detected so we are detected with extremely sensitive instruments.
The gravitational fields around Planets, Moons, and stars are often…
Strong enough to ‘trap’ other masses so they travel continuously around them as a path also known as an orbit.
What are some objects that are in orbit in our Solar system?
- Satellites
- All the planets around the Sun
- Moons
- Rocks and dust
What are artificial satellites used for?
Some are used for transmitting information such as internet and telephone conversations and to examine Earths weather patterns.
What are ellipses?
Oval shaped closed loops. Some are long, some are thin and some are near perfect circles.
How long does the moon take to orbit the Earth?
28 days.
Why do we see the moon in different phases?
The phases of the Moon are caused by the changing positions of the Moon, Earth, and the Sun.
How do tides form?
The combination of a weak gravitational pull frpm the Moon and the inertia of the Earth creates similarly-sized water forms.
