Transcript P1 - Foundation

P1 - Foundation
Part 3 – Space
Put these in order of smallest to
largest.
Star, Galaxy, Solar system, Moon,
Universe, Planet.
Moon
Planet
Star (sun)
Solar system
Galaxy
Universe
How was a star formed?
The Solar System is about
4,600 million years old. It
was formed from a nebula
– an enormous cloud of
dust and gas.
Over millions of years, gravity pulled the dust and gas together,
the temperature rose and pressure increased.
Eventually, the core started fusion and became the Sun.
What you need to know.
Stars about the same size as our Sun
These follow the left hand path:
Main sequence star → red giant → white
dwarf → black dwarf
Stars much bigger than our Sun
These follow the right hand path:
Main sequence star → red super giant →
supernova → neutron star or black hole
How you will be tested.
(i) State what a nebula is. (1)
(ii) A nebula eventually becomes a star.
Describe how a nebula becomes a star. (3)
(b) These are four stages in the evolution of a star similar to the Sun.
They are not in the correct order.
1. main sequence star
2. white dwarf
3. red giant
4. nebula
Write down the stages in the correct order. (2)
The first stage has been done for you.
. . . . . . . . . nebula . . . . . . . .
(cloud of) dust and/or
gases (1)
Answer
A description linking
three of the following
• when nebula reaches
a critical mass (1)
• nebula
collapses/contracts (1)
• (due to) gravitational
attraction (1) • (gets)
hot/ (makes) heat (1)
• forms a protostar (1)
• emits/produces light
/radiation(1)
Accept hydrogen/helium Accept idea that it is
where stars/planets are formed Ignore
rocks/smoke
Acceptable answers
correct sequence is not required when nebula
or dust/gas cloud is big (enough)
gases/dust/nebula come together/pulled
together/spiral /move faster
gravity/gravitational (potential) energy
transformed into thermal energy ignore starts
to burn/explodes/friction starts nuclear
reaction/fusion/ hydrogen turns into
helium/new elements
(1)
Mark
• (nebula) main sequence (star) (1)
AND
red giant
white dwarf (1) All three in correct order for 2
marks
• Red Giant
White Dwarf
(Main sequence) (1)
The Big Bang theory
The theory states that about 13.7 billion years ago all the
matter in the Universe began to enlarge rapidly in a hot
explosion, and it is still expanding today.
Evidence for the Big Bang includes:
• all the galaxies are moving away from us (red shift)
• the further away a galaxy is, the faster it is moving away. (red
shift)
• Scientists have also detected a cosmic microwave
background radiation or CMBR. This is received from all parts
of the Universe and is thought to be the heat left over from
the original explosion.
Steady state
The Steady State Theory suggests that as the
universe expands new matter is created, so that
the overall appearance of the universe never
changes.
There is no start or end in this theory.
Supported by red shift but NOT by CMBR.
How you will be tested on this.
Hubble's work led to the theory of the Big Bang.
Describe what is meant by the Big Bang theory. (2)
There are two theories for the origin of the Universe:
• the Big Bang Theory
• the Steady State Theory.
(i) Describe the evidence which supports the Big Bang
Theory. (2)
(ii) The Steady State Theory is not as widely accepted as the
Big Bang Theory.
Suggest a reason for this. (1)
A description including the
following points in a logical
order EITHER• red shift (1)
• detail of red shift (1)
OR• cosmic microwave
background (CMB) (1) • detail
of CMB (1)
Accept d• galaxies are
moving away • correct
wavelength / frequency change
• echo of the Big Bang
• uniform in all directions
• correct reference to
temperature of space
Answer
Acceptable answers
more evidence for the big bang evidence for the big bang
theory / converse
theory is more reliable /
repeatable / eq CMB does not
support Steady State
Galileo Galilei (1564-1642) was an Italian
astronomer working at a time when all Scientists
believed the earth was the centre of the
Universe and all planets orbited it (the
geocentric model). Using the newly invented
telescope he discovered that Jupiter had four
moons. As these moons were orbiting Jupiter
itself, this showed that not everything orbited
the Earth.
Heliocentric theory put the sun at the centre if
the universe.
We all see the sun and moon moving across the sky and both the theories explain this.
Only Heliocentric explains Jupiter's moons and why the planets move from East to West
(retrograde) unlike the Sun which goes West to East.
How you will be tested.
A long time ago, astronomers thought that the
Earth was the centre of the Universe.
This was called the geocentric model.
The evidence for this model came from
observations of the sky using the naked eye.
After the telescope was invented, astronomers
quickly gathered evidence which showed that the
geocentric model is not correct.
Describe the evidence both for the geocentric
model and against the geocentric model. (6)
Telescopes
Telescopes are devices used to observe the universe. There
are many different types and some are even sited in space.
Optical telescopes
Optical telescopes observe visible light from space.
Optical telescopes on the ground have some disadvantages:
• they can only be used at night
• they cannot be used if the weather is poor or cloudy
Other telescopes
• Radio telescopes detect radio waves coming from space.
• They can be used in bad weather because the radio waves
are not blocked by clouds as they pass through the
atmosphere. Radio telescopes can also be used in the
daytime as well as at night.
Telescopes in space
Telescopes in space can observe the whole sky and can
operate both night and day.
Above clouds so can’t be blocked by them.
No atmosphere bending light/blurring image.
No light pollution (unless it’s the sun).
They are difficult and expensive to launch and maintain.
If anything goes wrong, only astronauts can fix them.
Objects in the universe emit other electromagnetic
radiation such as infrared, X-rays and gamma rays. These
are all blocked by the Earth's atmosphere, but can be
detected by telescopes placed in orbit round the Earth.
How you will be tested.
Describe a benefit of using a telescope in space.
(2)
•Galileo’s telescope used a small lens to focus
the light.
Modern telescopes often use a large mirror
instead.
Explain how using a modern telescope helps
astronomers to understand the Universe better.
(3)
•
•
•
•
A description including any two of the following
• above the/no atmosphere (1)
• above the clouds / no clouds/no weather (1)
• image is clearer/ more detailed/ not distorted/not
blurred (1)
• • no light pollution (1)
• • no absorption (by atmosphere) of other named
radiations e.g. Xrays (1)
•
• no air/dust/pollution
• can see further /wider field of view/can use anytime
• IGNORE it is closer (to the stars/planets)
• IGNORE references to improving understanding /
knowledge of space
• An explanation to include the following points in a
logical order
• EITHER
• • idea of more {data / light} (captured) (1)
• • so can see dimmer objects (1)
• • so can identify {smaller / more distant} objects (1)
• OR
• • idea of more magnification (1)
• • so can see more detail (1)
• • so can identify {smaller objects}(1)
• image looks brighter
• image looks bigger
• more distant objects