New
New
Lesson 6 of 6
New
New
- Year 11
- AQA
The changing universe
I can describe the Big Bang Theory and evidence that supports it.
Lesson details
Key learning points
- Light from nearly all galaxies is redshifted, showing they're moving away, with distant galaxies receding faster.
- Evidence shows that galaxies were all in the same place about 14 billion years ago, showing their movement apart since.
- The Big Bang Theory suggests that the universe began from a very small region that was extremely hot and dense.
- A scientific theory is our best understanding based on all evidence and is subject to rigorous testing.
- We do not fully understand dark matter or dark energy.
Keywords
Redshift - the increase in the wavelength of light (and decrease in its frequency) caused by the movement of a star or galaxy away from us
Big Bang Theory - the theory that the our whole universe started in a hot, dense state, then expanded and cooled over fourteen billion years
CMBR - cosmic microwave background radiation is electromagnetic radiation produced in the hot early universe which has since been ‘stretched’ to the microwave part of the spectrum.
Common misconception
The Big Bang was an explosion in which existing matter blew up.
Describe the Big Bang as an expansion of space combined with the creation of all matter in the universe.
A balloon with several dots on it can be inflated to model the Big Bang. The dots represent galaxies, and the balloon represents the expanding space between them. Q4 on Task C is an optional research task into dark matter and dark energy that further develops KLP5.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.How do planets differ from a star?
How do planets differ from a star?
planets emit light radiation
planets are spherical
Q2.What is a comet?
What is a comet?
a rock pulled towards the Sun from the Asteroid Belt
an icy rock pulled towards the Sun from the orbit of a gas giant planet
a burning rock falling through Earth's atmosphere
Q3.How can we reduce the amount that stars twinkle when we observe them?
How can we reduce the amount that stars twinkle when we observe them?
by not looking at them through anything with a glass lens
by using a telescope with a large mirror
by looking on a completely clear night with no high clouds
we cannot reduce how much stars twinkle
Q4.Approximately how many stars are there in the Milky Way galaxy?
Approximately how many stars are there in the Milky Way galaxy?
300 (three hundred)
300 000 (three hundred thousand)
300 000 000 (three hundred million)
300 000 000 000 000 (three hundred trillion)
Q5.The speed at which a galaxy is moving away from us can be calculated from its .
The speed at which a galaxy is moving away from us can be calculated from its .
Q6.What absorbs particular frequencies of light to create absorption lines in light from a distant star?
What absorbs particular frequencies of light to create absorption lines in light from a distant star?
extremely hot gases in the star's core
nebulae between us and the star
Earth's atmosphere
Assessment exit quiz
6 Questions
Q1.Messier objects were first seen in the 17th century, using newly invented telescopes. In what ways is a Messier object different to a star?
Messier objects were first seen in the 17th century, using newly invented telescopes. In what ways is a Messier object different to a star?
they are smaller than stars
Q2.What is used to measure the distance to a distant galaxy?
What is used to measure the distance to a distant galaxy?
a variable (distant) galaxy of changing brightness
the redshift of the distant galaxy
the redshift of a star within the distant galaxy
Q3.What is the relationship between the movement of galaxies and their distance from us?
What is the relationship between the movement of galaxies and their distance from us?
the further away from us they are, the faster they are orbiting around us
the further away from us they are, the faster they are moving towards us
Q4.According to the Big Bang Theory, where was all matter about 13.7 billion years ago?
According to the Big Bang Theory, where was all matter about 13.7 billion years ago?
spread out much further than it is today
in much the same place as it is today
Q5.What best describes the Big Bang?
What best describes the Big Bang?
a contraction
an explosion
an implosion
Q6.Spiral galaxies are spinning faster and the universe is expanding more quickly than our current understanding has predicted. What ideas might explain what is going on and improve our understanding?
Spiral galaxies are spinning faster and the universe is expanding more quickly than our current understanding has predicted. What ideas might explain what is going on and improve our understanding?
dark force
dark power
