PISA Style Question
The Big Bang Theory
Read the text about the Big bang Theory.
In the 1920s, astronomer Edwin Hubble discovered the universe was not
static. Rather, it was expanding, a find that revealed the universe was
apparently born in an event we call the Big Bang.
The Big Bang is thought to have happened around 13.8 billion years. It is
thought to have begun as an unimaginably hot, dense point which rapidly
expanded outwards. As space expanded, the universe cooled and matter
formed. One second after the Big Bang, the universe was filled with
neutrons, protons, electrons, anti-electrons, photons and neutrinos.
During the first three minutes of the universe, the light elements were
born. Temperatures cooled from 1032 oC to 109 oC, and protons and
neutrons collided to make deuterium, an isotope of hydrogen. Most of the
deuterium combined to make helium, and trace amounts of lithium were
also generated.
Roughly 380,000 years after the Big Bang, matter cooled enough for
atoms to form, resulting in a transparent, electrically neutral gas. This
set loose the initial flash of electromagnetic radiation created during the
Big Bang, which is detectable today as cosmic microwave background
radiation. About 400 million years after the Big Bang, clumps of gas
collapsed enough to form the first stars and galaxies. A little after 9
billion years after the Big Bang, our solar system was born.
Question 1 : BIG BANG
In the text, the beginning of the universe is described. Which of the following
statements best describe how the universe evolved?
A
B
C
D
The temperature and density increased as the universe expanded.
The temperature and density decreased as the universe expanded.
The temperature increased and the density decreased as the universe
expanded.
The temperature decreased and the density increased as the universe
expanded.
Question 2 : BIG BANG
By what factor did the temperature of the universe decrease in the first three
minutes after the Big Bang?
A
B
C
D
A factor of 32
A factor of 23
A factor of 1023
A factor of about 3.5
Question 3 : BIG BANG
Which of these statements best describes the composition of the universe after one
second?
A
B
C
D
Positive and negative particles and electromagnetic radiation
Positive, negative and neutral particles
Neutral particles and electromagnetic radiation
Positive, negative and neutral particles and electromagnetic radiation.
Question 4 : BIG BANG
After 380,000 years atoms began to form. Circle ‘yes’ or ‘no’ for each statement that
describes the formation of atoms:
The formation of atoms
There are equal numbers of protons and neutrons in the nucleus
in order that the atom is neutral
Yes or No ?
Yes / No
There are equal numbers of protons and electrons in the nucleus
in order that the atom is neutral
Yes / No
There are equal numbers of protons and neutrons in the atom in
order that the atom is neutral
Yes / No
There are equal numbers of protons and electrons in the atom in
order that the atom is neutral
Yes / No
Question 5 : BIG BANG
Which of the following is the best estimate for the age of our solar system?
A
B
C
D
4.5 billion years
13.8 billion years
9 billion years
400 million years
Look at the diagram that represents the development of the universe
Question 6 : BIG BANG
Which of the following statements best describes the scales shown on the diagram?
A
B
C
D
The horizontal and vertical scales are both linear.
The horizontal scale is non-linear, the vertical scale is linear.
The horizontal scale is non-linear, we do not know whether or not the vertical
scale is linear.
Both scales are non-linear.
Question 7: BIG BANG
Which of the following is the closest estimate to the duration of the ‘Quark Soup’
era?
A
B
C
D
1 second
10-12 seconds
10-11 seconds
0.1 seconds
Question 8: BIG BANG
Use information from the diagram and from the text on page 1 to explain the likely
meaning of the term ‘parting company’ on the diagram.
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
SCORING : BIG BANG
Question 1
Full credit
B
The temperature and density decreased as the universe expanded.
No credit
Other responses
Missing
Narrative :
The text says that the universe began as ‘an unimaginably hot, dense point
which rapidly expanded outwards. As space expanded, the universe cooled
and matter formed.’ The question basically tests the candidate’s ability to relate
cooling to a decrease in temperature and expansion to a decrease in density.
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Low
Question 2
Full credit
C
A factor of 1023
No credit
Other responses
Missing
Narrative :
The factor by which the temperature decreases is arrived at by subtracting the
powers of ten (the difference between oC and K is negligible for such large
temperatures – and few GCSE candidates will be familiar with the Kelvin scale).
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Medium
Question 3
Full credit
D
Positive, negative and neutral particles and electromagnetic radiation.
No credit
Other responses
Missing
Narrative :
The passage states that ‘the universe was filled with neutrons, protons,
electrons, anti-electrons, photons and neutrinos’. It would be reasonable to
expect a GCSE candidate to recognise that protons are positive, electrons are
negative, neutrons are neutral and photons are electromagnetic radiation. This can
be deduced without knowing anything about neutrinos or anti-electrons.
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Medium
Question 4
Full credit
No No No Yes
No credit
Other responses
Missing
Narrative :
This requires a basic knowledge of atomic structure and the ability to recall that the
majority of elements in the periodic table have more neutrons than protons in the
nucleus.
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Question 5
Full credit
A
4.5 billion years
No credit
Other responses
Missing
Low
Narrative :
The candidate is required to extract the information that ‘A little after 9 billion
years after the Big Bang, our solar system was born’ and subtract it from the
estimated age of the universe of 13.8 billion years. This gives 4.5 billion years as the
closest answer. The other responses would typically be extracted directly from the
text without understanding what is required to arrive at the age of our solar system.
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Medium
Question 6
Full credit
C
The horizontal scale is non-linear, we do not know whether or not the vertical
scale is linear.
No Credit
Other responses
Missing
Narrative :
The question tests the candidate’s ability to recognise what is meant by a linear and
non-linear scale. The horizontal scale is clearly non-linear. Most readers may tend to
assume that the vertical scale is linear and that the gradient indicates the relative
rate of expansion, but there is nothing on the diagram to confirm that this is the
case.
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Medium
Question 7
Full credit
A
1 second
No credit
Other responses
Missing
Narrative :
According to the diagram the Quark Soup era is between 10-12 seconds and 1 second.
Since the difference between these two values is basically 1 second (a standard
scientific calculator returns an answer of 1 for this calculation) then A is the best
estimate. Answer D (0.1 seconds) demonstrates an understanding that the
difference between the values at the start and end of the Quark Soup era need to be
subtracted but a lack of understanding of what is meant by 10-12 and the nonlinearity of the scale.
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
Medium
Question 8 : BIG BANG
Full credit
Reference to the formation of atoms and a link to protons and neutrons already
having formed nuclei of simple elements and electrons beginning to orbit these
nuclei – hence ‘parting company’ of protons, neutrons and electrons from the ‘soup’
of the earlier era.
OR
Reference to the formation of atoms as described, and the ‘parting company’ of
protons/neutrons/electrons from the electromagnetic radiation which was then ‘let
loose’.
Partial credit
A partially correct attempt to explain either of the above ideas – perhaps with a lack
of clarity or some minor errors.
No credit
Other responses
Missing
Narrative :
Framework Categories
Knowledge type
2015 Framework
Competency
Context
Cognitive demand
High