Physics Gcse Ocr 21St Century P1

Front 1

How many planets are there? And what kind of path do they orbit? And what do they orbit? What other orbiting things?

Back 1

- 8 Planets
- Almost circular paths (ellipses)
- Around the sun
- Other smaller objects orbits sun (asteriods, dwarf planets, comets)
- Moons orbits several planets

Front 2

Describe the Sun

Back 2

- A huge star ( the Sun's diameter is over 100 times bigger than the Earth's)
- Very hot, and other stars and very far away
- Gives out/emits lots of light, hence you can see them very far away

Front 3

Describe Planets

Back 3

- Smaller than stars
- Just reflect light

Front 4

Describe Asteriods

Back 4

- Asteroids made of stuff left over from the formation of the solar system
- Found in the asteroid belt, between Mars and Jupiter
- Because they smallish lumps of rubble and rock didn't form a planet

Front 5

Describe Comet

Back 5

- Balls of rock, dust and ice
- Orbits the Sun in very elongated ellipses, often different planes from the planets (the Sun is near one orbit)
- As Comet approaches the Sun, ice melts, leaving a bright tail of gas and debris , which can be millions of kilometres long

Front 6

How was the Solar System formed?

Back 6

- Formed over very long periods from clouds of gases and dust in space
- 4500/5000 million years ago
- One cloud stared to get squeezed slightly
- Particles move closer to each other, gravity took over
- At the centre of the collapse, particles came together to form protostars
- Temperature high enough, a process at the centre called fusion starts - hydrogen nuclei joined together to make helium
- Fusion gives out massive amounts of heat and light - the Sun was born
- Chemical elements in clouds with heavier atoms than helium and hydrogen were also formed in the stars by fusion of different nuclei
- Around Sun, material from cloud containing hydrogen, helium, and heavier elements started to clump together, which becomes planets