In science we talked about gravity, the sun, stars, days and the four seasons. Gravity is a force that attracts all masses, gravity gives you weight not mass, mass never changes and is just how much ‘stuff’ is in an object, weight is a force measured in newtons and changes due to the pull of gravity, Here is the important formula: weight = mass x gravitational field strength ( which is 10 N on earth ).
The sun is the centre of our solar system
- a planet is something which orbits around a star
- the Sun is a star, the Earth is one of eight planets which orbit the sun
- the Sun is really huge and has a big mass, so it’s gravity is really strong, the pull from the Sun’s gravity is what keeps all the planets in their orbits
- the planets all move in elliptical orbits
- planets don’t give out light but the Sun and other stars do
- the Sun gives out a massive amount of energy which is transferred by light
A galaxy is a large collection of stars, our galaxy is the Milky Way, the Universe is made up of billions of galaxies. A light year is a unit of distance for measuring very long distances, 1 light year is 9.5 million million km, which means it takes the light from that star 1 year to get to our planet.
Day and night are due to the steady rotation of the Earth, the seasons are caused by the earth’s tilt.
I have already learned all of this so this was just a bit of revision.