Sun-Moon-and-Earth-Overview-Differentiated-Lesson

LO: To identify a star, planet and a satellite.
Understand key terms and words.
Know that planets and moons orbit

The Solar System
We live on planet Earth which is one of eight planets in our solar system. Our solar system is a collection of eight planets and their moons which orbit the Sun; along with asteroids, comets and meteoroids (which we may see as shooting stars).
Photo courtesy of leejayjee(@flickr.com) - granted under creative commons licence - attribution

Orbit
An orbit is the path that celestial bodies or satellites follow (like planets and moons) as they revolve around another body. The force of gravity causes this.
The object in orbit will always be much smaller than whatever it is orbiting as it is the larger object that has more gravitational pull.

Planet Earth
Our home is Earth which is a planet. A planet is a body which orbits a star and the closest star to us is the Sun, which planet Earth orbits.
Earth is the third closest planet to the Sun and is the fifth biggest planet in the solar system.
As with other planets and stars, the earth is round. This is caused by gravity pulling on the surface towards the centre of the plane.
Photo courtesy of Kevin M. Gill(@flickr.com) - granted under creative commons licence - attribution

Although the earth is round, it is not a perfect sphere. It’s actually an ‘oblate spheroid’. This just means it’s not the same diameter all the way around, in fact it’s a little larger around the equator.
Can you think why this is?

The Earth orbits the Sun. How long do you think it takes the Earth to orbit the sun once?
*Hint* Think about our calendar!

Seasons
Planet Earth takes 365 days (and 6 hours!) to orbit the sun once.
Have you ever wondered why we have different seasons? This is because of Earth’s tilt. At different times of the year the Sun’s light is shining on different parts of Earth, making it warmer. Why do you think there is snow at the North and South Pole?

Summer in the Southern Hemisphere is caused by more direct sunlight shining on to it.
This shows that while it is winter in the Northern Hemisphere it is summer in the Southern Hemisphere as there is more sunlight shining on that hemisphere.
The United Kingdom (in the Northern Hemisphere) is in Winter while South Africa, which is almost directly below but in the Southern Hemisphere it is summer because it has more sunlight shining on it.
SUN’S RAYS
NORTH POLE
UNITED KINGDOM
EQUATOR
SOUTH POLE
SOUTH AFRICA

This shows the United Kingdom in summer and South Africa in winter. Now there will be more sunlight shining on the Northern Hemisphere.
SUN’S RAYS
NORTH POLE
UNITED KINGDOM
EQUATOR
SOUTH POLE
SOUTH AFRICA

The Sun
Size
In the very centre of our solar system is The Sun, which is about 1.3 million times as big as planet Earth.
The diameter of the sun is about 880,000 miles, where the Earth is only 7972 miles.
EARTH
SUN

The Sun
Stars in the skies
Just like all the stars we can see in the night sky, our Sun is also a star. The stars that we see at night are just a lot, lot further away. The closest stars are about four light years away (a light year is the distance that light can travel in a year – this is such an unbelievably large distance it is hard to imagine).
Photo courtesy of thebadastronomer(@flickr.com) - granted under creative commons licence - attribution
A star is a huge ball of burning gas which is held together by gravity. They are a light source as they produce their own light.

The Sun is at the centre of our solar system and is orbited by eight planets, Earth being one of them.
Due to the Sun’s immense size it has a huge gravitational pull. This force keeps all the planets in our solar system in orbit.
Photo courtesy of leejayjee(@flickr.com) - granted under creative commons licence - attribution

The Moon
A ‘moon’ is the name of a body which orbits another body, as long as it is not a star.
Earth has its own moon which can be seen on any clear night. Just like how the Earth orbits the sun, the Moon orbits Earth.
Mercury and Venus are the only planets in the solar system which don’t have any moons at all (Saturn has 62 moons!).
At night the Moon gives us light, but it isn’t a light source like the Sun. It actually reflects the light from the Sun. Sometimes the Earth reflects light onto the moon. This is called ‘Earthshine’, and is why we can sometimes see the Moon during the daytime.
Photo courtesy of penguinbush(@flickr.com) - granted under creative commons licence - attribution

The Moon
Looking at the Moon from Earth, it looks like it keeps changing shape.
Can you think of why this might be?

The Moon
The best way to show how we see different phases of the Moon is by shining a torch on a ball in a dark room. As you move the torch around the ball, you will see different shadows.
Remember that the Sun (the torch) does not move, it just helps for this little experiment as it is just the shadows you are looking at.

The Moon’s Orbit
The moon takes 27 days (and 8 hours) to orbit the Earth. The Moon has an elliptical orbit rather than a circular orbit, which means it orbits the Earth in an egg shape. As a result the distance from the Earth to the Moon varies from 225,623 miles to 252,008 miles.

Plenary
What is a planet?
What is a star?
What is a moon?