Transcript Earth and Beyond - Swinton Community School

KS4 Earth and Beyond
© Boardworks Ltd 2003
What we once thought……
I don’t think so!!!
Copernicus
© Boardworks Ltd 2003
The Solar System
What makes up the Solar System?
The Sun
1. ___________

The planets
2. ___________
Moons
3. ___________
Asteroids
4. ___________
Comets
5. ___________
Our Sun is a star
Which of the above are light sources?
© Boardworks Ltd 2003
The Sun
The Sun is the source of energy for life on Earth. Where
does this energy come from?
The Sun is powered by nuclear fusion reactions.
Atomic nuclei are joined together (fused) due to the
high pressures inside the Sun.
What would happen on Earth if the Sun suddenly
disappeared?
All plants would die (no photosynthesis), animals
would die (no food source), temperatures would drop,
there would be no light, it would lead to the end of all
life on Earth.
© Boardworks Ltd 2003
The Sun and energy
Scientists were once confused.
If the Sun, they thought, was powered
by chemical reactions how has it
managed to stay ‘burning’ for millions of
years?
There must have been another process
producing the energy from the
Sun…………. Nuclear Fusion.
What two elements constitute most of the Sun?
Hydrogen and helium
How old is the Sun?
Four and a half billion years
© Boardworks Ltd 2003
Nuclear fusion
In nuclear fusion
reactions, lighter
nuclei are joined
together
(fused)……
….to form heavier
atomic nuclei.
This releases massive amounts or energy.
In our Sun, a typical
star, hydrogen is
being fused into
helium, this
provides the energy
for life on Earth.
When all the
hydrogen is used
up, other elements
will be fused
together to make
even heavier
elements.
Not all elements are
made in this way,
the heaviest
elements, some of
which are found in
your body can only
be made when stars
explode.
© Boardworks Ltd 2003
Stellar Evolution 1
Lighter stars like our Sun…..
Nebula collapses
due to gravity
Very small nebula form failed stars
Forms a
star like our
Sun
Expands to
form a Red
Giant
Outer layers of star drift away to
leave a dense White Dwarf
© Boardworks Ltd 2003
Stellar Evolution 2
Stars a lot heavier than our Sun…..
Larger nebula collapses
due to gravity
Super-dense
Neutron Star
formed
Red Giant collapses
violently in supernova
explosion
Forms a star more
massive than our Sun
Expand to form
Super-massive
Red Giant
© Boardworks Ltd 2003
Stellar Evolution 3
If the original nebula was massive enough, then when it goes
supernova it leaves a star so dense that not even light can escape
its gravitational pull.
This is called A Black Hole!
Some scientists believe that
there are Black Holes at the
centre of galaxies.
Homework Task:
If light can escape a Black
Hole, then how do we see it?
© Boardworks Ltd 2003
The life cycle of a star
© Boardworks Ltd 2003
Black Holes
How can you see a Black Hole?
You don’t (AND IT WOULDN’T BE BLACK).
You see the effect it has on nearby matter.
If there is a star nearby, matter from the star will
spiral into the Black Hole and as it does so the
matter emits X ray radiation which we can detect.
X rays
© Boardworks Ltd 2003
Put the following in a flow diagram to show the
life cycles of stars.
It has been started for you:
Red Giant
White dwarf
Star larger than
our Sun
Super-massive
Red Giant
Neutron star
Supernova
The Sun
smaller
nebula
Nebula
larger
nebula
© Boardworks Ltd 2003
The Lifecycle of a star:
White dwarf
Neutron star
Red Giant
Supernova
The Sun
smaller
nebula
Super-massive
Red Giant
Nebula
larger
nebula
Star larger than
our Sun
© Boardworks Ltd 2003
Star questions:
1. What two elements make up most of our Sun?
Hydrogen and helium
2. What is a nebula?
Cloud of gas and dust
3. What process has allowed the Sun to emit light and
heat radiation over billions of years?
Nuclear fusion
4. Which is the most dense, a white dwarf or a neutron
star?
Neutron star
5. Describe the possible fate of a star similar to our Sun.
 Red Giant  White Dwarf
© Boardworks Ltd 2003
The Sun’s gravity:
1. What force keeps the planets in orbit around the Sun?
Gravity
2. Which planet shown will feel this force ………..
a) The strongest?
b) The weakest?
Not to scale!
© Boardworks Ltd 2003
Where did the Sun come from?
Put the sentences in the correct order.
Gravity causes a dust and
gas cloud to condense into
a smaller volume
This causes the
“nebula” to collapse
When the temperature and
pressure are great enough
nuclear fusion starts.
As the nebula collapses,
temperatures and pressures
inside the nebula increase.
Eventually gravity and the
outward pressure of
escaping energy is
balanced, and at this stage
it is called a star.
© Boardworks Ltd 2003
Satellites
1. What are the two types of satellite?
Natural and artificial
2. Give an example of each type?
Natural – The Moon
Artificial – Navigation, spy, military,
weather, communications
3. Why are some satellites, like the
Hubble Space Telescope shown, put
into space?
So the Earth’s atmosphere does not get in the way.
© Boardworks Ltd 2003
Polar and Geo stationery
Geo stationery
Satellites spin around at the
same speed as the Earth, stay
above the same location on
the Earth’s surface.
Polar
Satellites orbit around the
poles, whilst the Earth spins
underneath, allowing large
areas of Earth to be seen.
© Boardworks Ltd 2003
Say if the satellites below have a polar orbit
or a geo-stationery orbit:
Communications
Weather
Spy
Navigation
Weather
Navigation
Polar
Geo stationery
Spy
Communications
© Boardworks Ltd 2003
Comparing orbits
Use a textbook or other resource to fill in the table below:
Polar
Geo stationery
Height of orbit
lower
higher
Orbital speed
faster
slower
Orbits per day
3-4
1
Orbit position
around poles
above equator
Example
weather
communications
© Boardworks Ltd 2003
Can you put these in the correct size order,
smallest first?
1.
Earth
__________
2.
The Sun
__________
3.
The Solar System
__________
4.
The Milky Way
__________
5.
The Universe
__________
The Sun
The Solar System
The Universe
Earth
The Milky Way
© Boardworks Ltd 2003
Match the words and definitions:
A star
There are nine of these in our
Solar System. The Earth is one.
A planet
Our Sun is one.
A galaxy
Billions of stars together - ours
is called the Milky Way.
The Universe
The Solar
System
The Sun, planets, moons,
asteroids and comets make up
this.
All the galaxies and everything
else.
© Boardworks Ltd 2003
Identify the different bodies:
A galaxy
A star
The Universe
© Boardworks Ltd 2003
Red shifts
Listen to the noise a plane makes as it passes you……


…then when it is moving
away from you, it sounds
lower pitched.


As the plane
approaches it sounds
higher pitched……….
This is due to the Doppler effect, the same thing happens with
light. Approaching objects have the wavelength of the light
they emit shortened (red-shifted), receding objects have the
wavelength of light they emit increased (blue-shifted).
© Boardworks Ltd 2003
Hubble
Hubble was a famous scientist who examined the light
from nearby galaxies. He noticed two things:
1. That most of the galaxies’ light was shifted towards the
red end of the spectrum;
2. The further away a galaxy was, the more its light was
red-shifted.
From these observations he concluded:
1. That most galaxies were moving away from our own;
2. The further away a galaxy was, the faster it was moving
away from us;
3. And therefore he concluded that the universe is
expanding.
© Boardworks Ltd 2003
© Boardworks Ltd 2003
Fate of the Universe Research
What is the possible origin and fate of the Universe?
Using a textbook, CD-Rom or the internet try to find two
different theories about the origins and fate of the
Universe.
Hints:
The Big Crunch
Hubble
Steady State Theory
Cosmic microwave
background radiation
The Big Bang
Closed Universe
Expanding Universe
Density
Red-shifts
Open Universe
© Boardworks Ltd 2003
The Big Bang Theory
This theory states that the Universe is expanding due to
a large ‘explosion’ (big bang) billions of years ago.
Evidence?
1. The Cosmic Microwave Background Radiation (CMB), which is
thought to be an ‘echo’ of the initial explosion.
2. Hubble’s observations about red-shifted light.
There are different fates for the Universe with this theory:
1. The Universe expands for ever if there is not enough gravity to halt
its expansion – OPEN UNIVERSE.
2. The Universe will eventually start to contract due to gravity –
CLOSED UNIVERSE.
© Boardworks Ltd 2003
Steady State Theory
This theory states that the Universe is expanding and
as it expands matter is created to maintain a uniform
universal density of matter.
Evidence?
Hubble’s observations about red-shifted light.
However:
This theory has become less popular since the discovery of
Cosmic Microwave Background Radiation (CMB).
© Boardworks Ltd 2003
Are we alone?
In pairs discuss the points below and then share you ideas
with the rest of the group.


For life to exist there
  must
be liquid water,
on a planet or moon
and oxygen.

The Universe is so big,
even if there are aliens,
We are all aliens, life began

they are too far away for us
on comets and asteroids

to ever meet them.
and transferred to the Earth
when they collided with it.
Life exists on Earth

and only on Earth.
If there are aliens they

will probably not look
If there are aliens
they would have
contacted us by now.
like you or me.

You have 10 minutes!!!
© Boardworks Ltd 2003
What is the name of the furthest planet
from the Sun?
A. Earth
B. Jupiter
C. Pluto

D. Venus
© Boardworks Ltd 2003
Why is Venus hotter than Mercury?
A. It is closer to the Sun
B. It is further away from the Sun
C. Acid Rain
D. The Greenhouse Effect

© Boardworks Ltd 2003
What object from the Solar System is shown?
A. Comet

B. Planet
C. Asteroid
D. Moon
© Boardworks Ltd 2003
What elements is the Sun mostly made from?
A. Iron and nickel
B. Strontium
C. Hydrogen and helium

D. Helium and neon
© Boardworks Ltd 2003
Which of these planets has two moons
called ‘Fear’ and ‘Dread’?
A. Earth
B. Venus
C. Saturn
D. Mars

© Boardworks Ltd 2003