Science Exam Revision

- Space science - Physics - (No chemistry ye) (add if needed please)

Star

a fixed luminous point in the night sky which is a large, remote incandescent body like the sun.

Planet

a celestial body moving in an elliptical orbit around a star.

Solar system

the gravitationally bound system of the sun and the objects that orbit it.

Galaxy

a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.

Universe

space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy.

Apparent magnitude

the brightness of the light as observed from the earth

Absolute magnitude

the brightness of the light from a set distance (10 parsecs)

Light years

it tells us the distance that light would travel in a year. 1 light year is 9.5 trillion km.

Parsecs (pc)

it is equivalent to 3.26 light years.

Supernova

it is an explosion of a Super Giant

How can Nuclear fusion emit light

at the core, 2 hydrogen atoms fuse together to create helium. This produces energy which comes off in the form of heat and light.

Red shift

when an object more red as the object is moving further away. This is because of the doppler effect.

Blue shift

when an object is more blue it is moving closer to us. This is because of the doppler effect.

Scalors

only has a magnitude

Vectors

has a magnitude and a direction

Examples of scalors

mass
speed
distance

Examples of vectors

time
displacement
force
velocity
weight
acceleration (gravity)

Converting Astronomical units to Kilometres

1 AU ——> 150 million km

Describe how Aboriginal Australians used stars

they use the stars to know the different seasons so they know when to go hunting and for dreamtime stories.

Describe the Big Bang Theory and any evidence supporting this theory

is a theory that states the universe is created at a certain point. At that point it expanded and stretched to how big it is now.

EVIDENCE:

Edwin Hubble noticed that some galaxies where moving away and moving towards us. Over time some stars started to admit red or blue light.
The doppler effect is the apparent change in frequency when a moving object gets closer to an observer. This can be explained by the Doppler Effect, if the star moves away, the light will decrease therefore red light appears. This shows that the universe is slowly expanding and that nothing is taking the place between Earth and Sirius.

Cosmic Background Radiation: the dish in Parkes NSW was experiencing small disturbances. They thought it was pigeon poop, but they found an afterglow of the Big Bang Theory.

factor that affects a star’s colour

temperature

factors that affect a star’s brightness

temperature and distance

Interpret a Hertzsprung-Russell Diagram

the Hertzsprung-Russell is a plot of star brightness (measured as luminosity) against star temperature/colour. 
remember the luminosity scale gives us an idea of how bright a star is compared to our sun

Newtons 3 laws

1. Inertia

2. F=ma

3. Action reaction

Inertia

an object at rest stays at rest and an object in motion stays in motion with the same speed and direction unless acted on by an unbalanced force.

F=ma

for a constant force, mass and acceleration inversely proportional (one up, one down)
for a constant mass, force is proportional to the acceleration (both up)

Action reaction

whenever a body exerts a force on another body, the second body exerts a force equal in magnitude but opposite in direction.