science stars and global warming

define a star

a large ball of hot glowing plasma

define nuclear fusion

a high energy reaction in which two lighter atomic nuclei fuse to form a heavier nucleus

what do stars contain

hydrogen and helium

where does nuclear fusion occur and what is released in this reaction

in the core of stars , releases energy as electromagnetic radiation (light) and releases heat

apparent magnitude definition

a measure of how bright a star “appears” to be from early

absolute magnitude definition

measures a stars brightness if all stars are all the same distance

what is brighter sun or moon and why

sun bc the more negative the value the brighter the star

why does star A appear to be the same brightness as star B, despite star A being further away

A has a higher absolute magnitude, A and B have the same apparent magnitude

how do stars vary

size, mass, temperature, and brightness

how can we compare stars temperature

by analysing their colour, blue stars r hotter, red stars r colder

what’s the r hertzsprung russel diagram and what does it do

a method of displaying star data on a graph and shows the relationship between a stars brightness and temperature. it helps classify stars by showing where they r in their life cycle. it shows patterns in star types like main sequence stars, supergiants, giants, and white dwarfs

what trends do y observe on this hertzsprung russel diagram

most stars fall on a narrow band called the main sequence

define absolute magnitude

measures a stars brightness, if all stars are the same distance

define apparent magnitude

a measure of how bright a star “appears” to be from earth

draw a labelled diagram to show stellar parallax

where would u find the following on an HR(hertz spring russel) diagram:

• white drawf

• super giants

• main sequence

Hertzsprung-Russell (H-R) diagram, which compares temperature (left to right, hot to cool) and luminosity (bottom to top, dim to bright):

🌟1. Main Sequence

• Location: From the top left to the bottom right (a diagonal line).

• Includes most stars (like our Sun).

• Hot, bright stars are at the top left; cool, dim ones at the bottom right.

🌟2. Supergiants

• Location: At the top right.

• Very cool but extremely bright because they are huge in size.

🌟3. White Dwarfs

• Location: At the bottom left.

• Very hot but dim because they are small and don’t produce much light.

free space yay keep going stay focused

explain where nuclear fusion occurs

Nuclear fusion happens in the cores of stars, where hydrogen atoms join to make helium and release energy.

draw a diagram showing the doppler effect

state the effect in the fréquence of sound where a car is coming towards u and going away from u

This is called the Doppler Effect.

🚗💨 When a car is

coming towards you

:

• The sound waves are compressed

• You hear a higher frequency (higher pitch)

🚗↘ When the car is

going away from you

:

• The sound waves are stretched out

• You hear a lower frequency (lower pitch)

free don’t give up

relate to the similarity of light and red shift: galaxies moving away from ours and galaxies moving towards ours

• Redshift happens when a galaxy is moving away from us. The light waves it emits get stretched out, making the light appear more red (longer wavelength).

• Blueshift happens when a galaxy is moving towards us. The light waves get compressed, making the light appear more blue (shorter wavelength).

So, both redshift and blueshift happen because of the Doppler effect — just like sound changes pitch when a car drives past you. For galaxies, the change in the light’s wavelength tells us if they are moving closer or farther away.

draw a flow chart to show the life cycle of a star

draw a labelled diagram of the water cycle

draw a labelled diagram of the carbon cycle

describe greeenhohse gases and give some examples

Greenhouse gases are gases in the Earth’s atmosphere that trap heat. They let sunlight in but stop some of the heat from leaving the planet, kind of like a blanket. This process is called the greenhouse effect, and it helps keep Earth warm enough for life. But too many greenhouse gases can cause global warming. EG carbon dioxide, methane, nitrous oxide, water vapour, ozone

describe the effects of the enhanced green house effect

1. Global warming
   – Earth’s average temperature rises, causing long-term climate change.

2. Melting ice caps and glaciers
   – Leads to rising sea levels and loss of habitats (like for polar bears).

3. More extreme weather
   – Stronger storms, floods, droughts, and heatwaves become more common.

4. Rising sea levels
   – Causes flooding in coastal areas and small islands.

5. Ecosystem damage
   – Some animals and plants can’t adapt fast enough and may die out.

6. Impact on food and water
   – Droughts or floods affect crops and clean water supply.

discuss ways we can reduce our effects on the enhanced greenhouse effect

1. Use renewable energy
   – Switching to solar, wind, or hydro power reduces carbon emissions from burning fossil fuels.

2. Use public transport, walk, or bike
   – Fewer cars on the road means less carbon dioxide released into the atmosphere.

3. Reduce electricity use
   – Turning off lights and using energy-efficient appliances lowers greenhouse gas production.

4. Plant more trees
   – Trees absorb carbon dioxide, helping to clean the air and cool the planet.

5. Eat less meat
   – Producing meat, especially beef, releases methane—a powerful greenhouse gas.

6. Recycle and reduce waste
   – Recycling uses less energy than making new products, and reducing waste cuts landfill gases.

7. Buy local and sustainable products
   – This lowers emissions from transport and supports eco-friendly farming or production methods.

describe the four spheres

1. Atmosphere
   – The layer of gases surrounding Earth that we breathe and that controls weather and climate.

2. Hydrosphere
   – All the water on Earth, including oceans, rivers, lakes, and underground water.

3. Lithosphere
   – The solid, rocky outer part of the Earth including the crust and upper mantle, where landforms like mountains and soil exist.

4. Biosphere
   – All living things on Earth, including plants, animals, and humans, interacting with the other spheres.

propose a reason why a star with greater mass (eg rigel) could be smaller in size than a star with a lower mass (eg betelgeuse)

rigel is more dense than betelgeuse is.

betelgeuse is at a later stage in its life cycle and is shedding its outer layers. this makes it larger than rigel.

what gases do stars mostly contain

hydrogen and helium

what’s a light year

the distance light travels in one year (9.46 trillion km)

what is a stellar parallax

a change in the apparent position of a star against its background when viewed from two different positions

define galaxy

a group of stars held together by gravity

how fast does light travel

300,000km/s

why can we see stars and galaxies

light travels from them to earth over a period of time

how long does it take light from the sun to reach earth

about 8 minutes

what does parallax enable us to do

calculate distance between the earth and a star

respiration, combustion, consumption, and coal formation are processes found in the carbon cycle. State which sphere carbon starts in, and where it ends up.

respiration: biosphere to atmosphere

combustion: lithosphere to atmosphere

consumption: biosphere (plants) to biosphere (animals)

coal formation: biosphere to lithosphere

how are galaxies classified

by their shape: spiral elliptical and irregular

define nebula

a large cloud of gas and dust in space, often the site of star formation or the remnants of a stars explosion

define protostar

a young star that’s still gathering mass but has not yet started nuclear fusion

define supernovae

massive explosions that occur at the end of a stars life cycle

how does a protostar form

gravity pulls particles in a nebula closer together

how does a star die

the star runs out of elements to fuse

what do average sized stars form

red giants

what happens to an average sized star when it runs out of fuel

they form a white dwarf

what do massive stars (>8 time the mass of the sun) form

red supergiants

what happens after supergiants eventually result in a supernova

• smaller supergiants will form a neutron star

• larger supergiants will form a black hole

how is a star born

particles in space are attracted to each other by gravity. they form clouds which become nebulae when enough particles are in the same space. in nebulae, the particles collapse into protostars. the pressure involved raise the temperature to the point where nuclear fusion can occur. once this happens, a star is born.

how is a black dwarf formed

stars eventually run out of hydrogen, and start to fuse helium. stars doing this are red giants. once fusion stops they eject their outer layers as a planetary nebula. what is left behind is a white dwarf. a white dwarf will slowly cool until it becomes a black dwarf

what r the 3 pathways star can take as it runs out of fuel

1. Low-Mass Stars (like our Sun)

➡ White Dwarf

• The star expands into a red giant.

• It sheds its outer layers into space, forming a planetary nebula.

• The hot, dense core that’s left becomes a white dwarf.

• Then the white dwarf cools and becomes a black dwarf, making it stop glowing so technically becomes a black dwarf

2. Medium to High-Mass Stars

➡ Neutron Star

• The star becomes a red supergiant.

• It explodes in a powerful supernova.

• The leftover core becomes a super-dense neutron star.

3. Very Massive Stars

➡ Black Hole

• Also ends as a supernova.

• If the remaining core is massive enough, it collapses into a black hole — a point with gravity so strong, not even light can escape.

what force causes to the particles of the universe to slowly move towards each other

gravity

which gas is the main component of a protostar

hydrogen

construct the equation for the fusion of deuterium and tritium

deuterium + tritium → helium + neutron + energy

name the stars that r 10 times as large as the sun or more

super giants

if a supernova occurs in a smaller star, recall what the star becomes

neutron star

FREE CARD U GOT THIS KEEP GOING

it a supernova occurs in a larger star, recall what the star becomes

black hole

process of the massive explosion called a supernova

• stars which r much larger than our own are called supergiants

• they begin life as blue supergiants and turn into red supergiants as they run out of hydrogen

• their size means they can fuse heavier and heavier elements all the way to iron

• eventually the star collapses under its own gravity, creating a massive explosion called a supernova

what is a fact about black holes

• the biggest stars turn into them

• black jokes have such great gravitational pulls that not even night can escape them

what do u do when drawing a line of best fit

1. ignore outliers

2. the line must reflect the trend (this could be curved)

3. the line must be balanced (approx equal number of points above and below

4. don’t force the line to pass thru specific points

explain the phenomenon shown in the image below

• star A and B have the same apparent brightness

• star A has a larger absolute brightness

• the two stars appear the same brightness from earth, as star A is much further away than star B

when stars form, interstellar hydrogen clouds undergo gravitational collapse and shrink . what do they form first?

a proto star

define quarks

fundamental particles that combine to form protons, neutrons , and other particles

what did edwin hubble discover in 1929

other galaxies were moving away from us. the further away the galaxy is the faster it’s moving away. he concluded that if u run the universe in reverse, everything must’ve come from a single point

what is the big bang theory

1. the universe came into existence from a single hot and dense point called a singularity

2. space expanded rapidly and silently from this point

3. over time, the universe cooled and matter formed. this includes the stars and planets in the universe we see (and are part of) today

provide evidence for the big bang theory

1. microwave background: radio antenna have picked up background noise, this is cosmic radiation from the big bang

2. mixtures of elements: the amount of hydrogen and heavier elements formed should be proportional to the amount of energy available. satellites have detected this

3. the universe is changing: when we examine distant galaxies, we’re looking back in time. we can see galaxy formation back in time

summarise the formation of the universe

1.

Big Bang (13.8 billion years ago)

The universe began as a tiny, hot, dense point and suddenly expanded.

2.

Cooling and Expansion

As it expanded, the universe cooled and formed simple particles.

3.

Formation of Atoms (about 380,000 years later)

Particles joined to form atoms (mainly hydrogen and helium); light could now travel.

4.

First Stars and Galaxies Form

Gravity formed the first stars and galaxies; stars began nuclear fusion.

5.

Creation of Heavier Elements

Big stars exploded (supernovae), spreading elements needed for life.

6.

Formation of Solar Systems (about 4.6 billion years ago)

Gas and dust formed new stars and planets—like our solar system.

what happened after the big bang

1. 1 second — boiling soup of fundamental parked (electrons, quarks, etc)

2. 3 seconds to 300,000 years — super hot fog

3. 300,000 years — elemental particles combine to form atom

4. 1 billion years — galaxy formation begins

5. 3.5 billion years — dying stars produce heavier elements which will form new stars and planets

what does the big bang describe?

the formation of the universe — the beginning of the universe as a massive expansion from a hot , dense state

what observation supports the big bang theory

the universe is expanding, with galaxies moving away from each other, supports the big bang theory

what is the red shift

when the light spectrum is moved towards the red end

what’s the doppler effect

a change in frequency of a wave as the source and observer move towards or away from each other

how does light and sound travel

waves. light is transverse waves up and down. sound is longitudinal waves back and forth

describe the movement of the frequency of sound waves

• frequency increases as source moves towards u - each wave is emitted at a point closer to u, so the waves bunch up

• frequency decreases as source moves away from u - wfh eave is emitter at a point further from uc, so the waves spread out

what did edwin hubble examine in the 1920s

the spectra of light absorbed and emitted by galaxies. these spectra revealed info about the velocity of the galaxy

what did hubble notice about the spectra of light

lines were shifted in the red direction (red shift). this means light is reaching us with a lower frequency which suggests galaxies are moving away from us

why are distant galaxies travelling faster away from us

they have more red shifted spectra. this provides compelling t evidence for the BigBangTheory and has been used to determine that the expansion of the universe is accelerating

what is an absorption spectrum

the litht seen from a star that’s missing specific wavelengths

what’s an emission spectrum

the light emitted from an object that has absorbed light from somewhere else. it’s a collection of coloured bands

how to know if ur looking at an absorption spectrum or emission spectrum

• Absorption = Rainbow with Missing Lines

• Emission = Black with Bright Lines

draw a diagram demonstrating the doppler effect and label the sound wave frequencies

what’s a continuous spectrum

a complete rainbow with no dark lines or missing spots.