Hi everyone I'm Roger Benson I'm a tutor in
Earth Sciences at St Edmund Hall and I'm also
in the Earth Sciences department as a palaeontologist
so I teach courses related to palaeontology,
field geology and sedimentary geology.
Hi everyone I'm Erin Saupe I'm a tutorial
fellow at St Hugh's college and I'm in the
faculty of the Department of Earth Sciences
at Oxford.
I'm also a palaeontologist and I also teach
courses on evolution, invertebrate palaeontology,
quantitative palaeobiology and sedimentology.
So today Erin and I are going to show you
a demonstration interview with one of our
current students to give you an idea of what
online interviews in earth sciences are like.
Before that I'm just going to explain what
happens in earth sciences interviews and what
we're looking for when you apply to study
earth sciences at Oxford.
So for earth sciences we don't set any admissions
tests so you don't have to sit an exam before
coming to interview we also don't set you
any pre-interview reading or similar so you
come into the interview really with a sort
of fresh mind and we're looking to evaluate
you based on how you respond to our questions
and really our main goal is to get to the
bottom of how you think and how you respond
to new challenges.
So it's really okay if you don't know the
answers to questions right away because we
want to see how you tackle new challenges
and how you apply yourself to questions.
And on that note ... what we're looking for
specifically, so students are selected on
the basis of some key things that are outlined
on our website so those are reasoning ability,
mathematical ability and potential, independence
of creative thought so are you able to sort
of think laterally and generate hypotheses,
your capacity to absorb information and use
new ideas to apply it to perhaps unfamiliar
... situations, your spirit of inquiry so
meaning how excited are you about learning
new information and about the earth sciences,
your ability to observe the natural world
so are you accurate and critical about your
observations, and then your appreciation for
field-based laboratory and theoretical nature
of earth sciences, so do you like the multi-disciplinary
nature of the earth sciences where you are
able to get into the field do fun experiments
in the laboratory as well as think more theoretically
and quantitatively.
Yeah that's right and while you're applying
you've probably had some thoughts about why
you want to apply to an earth sciences degree
rather than a different science degree such
as physics or chemistry.
It's likely that you'll be asked that type
of question in an interview just so that we
have an understanding of your motivation for
studying this specific course rather than
any other.
So in our process students have two interviews,
so all of our shortlisted applicants have
two interviews with tutors representing probably
three or four different colleges, and that's
to ensure you're seen by representatives of
as many different colleges as possible, and
in fact when you apply to earth sciences in
Oxford we don't know which college you apply
to our process is college blind, so all candidates
who are evaluated on an equal footing regardless
of which college they apply to.
Hi Jamie nice to meet you, I'm Erin Saupe
I'm a tutorial fellow at St Hugh's college
and I'm a faculty member here in the Department
of Earth Sciences at the University of Oxford
and I'm a palaeontologist.
Hi Jamie I'm Roger Benson and I'm a tutor
at St Edmund Hall I'm also a palaeontologist
in the department.
So we'll both interview you today, thank you
for coming and thank you for your time.
I guess the first thing to do is to say how
the interview will proceed so we'll ask you
some questions we'll start with some more
general questions and then we'll get into
some questions that are designed to explore
how you think scientifically.
The main thing to say about those questions
is not to be too anxious about them and not
to worry too much about getting the right
answers straight away, our main goal is just
to see how you think about problems, so we
want you to do really well ... so if it's
possible try to enjoy the process and feel
free to tell us what you're thinking even
if you're not sure that it's quite right and
will help to sort of guide you through the
process and see how you approach the questions
that we give you.
Yeah absolutely it's about thinking ... out
loud so that we can get a sense of your thought
process so the first question we want to ask
you is why Oxford and why do you want to study
Earth Sciences in particular here at Oxford?
Yeah so ... what I particularly liked about
the Earth Sciences course here is it stays
more broad than at other universities so I
kind of like the idea of ... so I think in
the first few years at least you take all
of the courses at the same time and I just
like the idea of getting a really broad basis
for the knowledge before like specializing
too early.
And why are you interested in earth sciences
in particular?
Yeah so it's just kind of always been an area
I'm interested in, like stuff like volcanoes
and earthquakes, it's kind of naturally cool,
but I mean weather stuff has just been what
I've always been interested in and it's just
been interested in how those systems work.
Right ... all right so ... I'm going to ask
you the first question and it's thinking about
how climate change may affect our earth systems.
As you know climate is changing ... it's getting
warmer and there are many effects of that
warming on earth systems including the melting
of ice.
So there's a lot of ice on Antarctica and
let's say we're interested in estimating how
much ... sea level would rise if we melt all
of the ice on Antarctica and dump it in to
the oceans.
So we want to melt all the ice, well we don't
want to melt all the ice but we want to estimate
if all the ice melted and we dumped it into
the oceans how much would sea level increase.
But let's say that the only pieces of information
we have are four pieces of information: the
volume of ice, the density of water, the density
of ice and then the surface area of the oceans.
So what I'd like you to do is think about
how you might approach this problem to roughly
estimate how much sea level would rise if
you only have those four pieces of information.
So I'm going to go to Miro right now and write
down those pieces of information that we have
and we can abbreviate them as well so let's
make this a bit bigger
Density of ice is dice and then surface area
of the oceans, so these are our four pieces
of information
that ... we have.
Can you start to think about how we might
roughly estimate that increase in sea level
using only these pieces of information?
Okay and can I write on board?
Yeah absolutely.
All right so I'll start off with the ones
that I can kind of know a bit more, the density
of water is just I think a thousand kilograms
per meter cube it's like slightly under but...
Yeah ... that's exactly right but actually
we're not going to use any numbers here so
you don't actually need to know that value
of the density of water, although that is
right.
Right so what I want you to do is actually
just use these abbreviations and think about
how you would estimate that value but not
actually get enough at this point in time.
So how would I estimate the density of water
using other values?
How would you estimate the increase in sea
levels, so that height increase, using only
these four pieces of information?
We don't want the actual values, we don't
care about that, we're just pretending like
we have these actual values here with abbreviations
yeah.
So the way I'm thinking of it now is the change
in height so I will write, so change in height
... would be equal to
so will be to do with the surface area?
Yep.
Yeah so let me just think about how it's related
sorry.
No that's great.
We like people to think it's fine.
It'll be the volume divided by the surface
area, so the volume of water divided by the
surface area of the oceans.
Right yep ... that's exactly right.
And to get the volume of water we would multiply
the volume of ice.
So Jamie why don't you just write down, so
that that's exactly right, so why don't you
just write down the volume of h2o divided
by the surface area of the oceans because
that's right that that's what we want to ultimately
get at is that change right.
Sorry for the handwriting this is a bit different.
No problem at all it's not a problem.
It's difficult to write on ... a Miro.
You haven't seen our handwriting yet.
Oh yeah, so should I keep them going?
Please do.
All right so to get at the volume of h2o
... that's going to be equal to, it's going
to be related to the volume of ice, and that's
going to be just multiplied by the coefficient
related the density of water and the density
of ice.
Let me just think about what goes in ....
Yeah great so we know that the volume of water
is related to the volume of ice but we need
to think about how it is related and how we
can take the pieces of information that we
have like the density of water and the density
of ice to get that volume of water.
Yeah this is just something that should be
pretty easy, I can't remember exactly how
it works I just need to think it through,
so ... if I'm saying that the density of water
is higher than the density of ice, so let
me just write this down
so
oh no go ahead go ahead.
Okay so I'm just trying to remember which
way to write down I think it's water on top
but I just want to make sure.
So.
Oh yeah.
Oh go ahead sorry I don't mean to interrupt
you.
I'm just trying to so if I'm going to say
the volume of water is going to be less than
the volume of ice and I know that the density
of water is less than the density of ice okay
yeah it's got to be density of water on top
What's the property that you're trying to
conserve?
Volume isn't conserved and the densities are
different but what is conserved that you're
thinking about?
What is conserved?
Yeah so how do we relate density and volume?
Mass?
Yeah mass is conserved, exactly, so what is
density?
Mass per volume.
Mass per volume exactly so if if we were to
just very systematically walk through ... the
pieces of information that ... we do have
so we have the ... first of all we start off
with ice on Antarctica right, so we have ... the
volume of ice, we have the density of ice,
so what can we get from that?
We can calculate the mass of the ice.
We can calculate the mass of the ice exactly.
So if mass is conserved, you've said, why
don't you start by writing out an equation
that says that the mass is conserved.
Okay so ...
okay yeah so the mass of total ice great,
so 'mice'
is equal to, actually ... let's do this differently
... Okay.
No problem.
So mice ... start
it's at the start of melting plus mass water
now let's start
but hopefully this can all be fit on anything
will be equal to
let me move across
Yeah that's right
That's the equation.
That's great so you've got mass of ice at
the start plus mass of water at the start
equals mass of ice at the end plus mass of
water at the end, but let's make the simplifying
assumption that we melt all the ice and the
ice at the end is zero and that we started
with no water or we're just subtracting, yeah
there you go.
There you go right that's great, so we know
that the mass of ice at the start is going
to equal the mass of water at the end, so
then since we can substitute the mass of ice
for the mass of water, what do we need to
do?
We just need to get the mass of ice right,
and that's a piece of information we don't
have here, so how how would we get that?
Okay so to get the mass of the ice ... so
we have the volume of ice and we have the
density of ice, so mass is just volume divided
by the density
so multiplied.
Right all right there we go, very nice, excellent
,so why don't we write that out, so mice
so mice is equal to ... I can't remember the
names, vice.
Yep.
Mice, vice ... exactly there you go.
Very nice.
Very nice indeed.
All right so now we have the mass of ice and
you just said ... that equals the mass of
water so now what what can we do?
Let's write this down...
Perfect yep and that's great that you're writing
things down to help us
And we can relate the mass of the water to
the change in height
the volume at least.
Yeah.
Earlier you were trying to get an expression
that related the volume of water, so the volume
of ice, yeah so why don't you use what you've
got so far to change your equation that does
the equivalencies of the masses into one that
uses volumes and densities instead.
Okay so ... to get some point I switch from
using h2o to water okay I'll keep on with
water ... so this will be equal to m water
over
d water, density of water.
Perfect yeah great.
Which are both known at this point.
Yeah you do know yeah.
And then once we have the volume and then
volume of water is also equal to ... its surface
area, which would be a oceans, at some point
I also switch from oceans to water.
That's okay that's fine.
Multiplied by the height
and this is now known this will give another
start so just rearrange
That's it so now you have just used the information
and how we understand density to be related
to mass and volume to get that change in height
so to get how much we think sea level will
increase if we melt all of the ice on Antarctica
and dump it into the oceans.
Obviously this is a really rough calculation
and there's a lot of assumptions that we made
when we did this calculation but if we were
to make these sorts of assumptions and ... put
in some real numbers we would get approximately
about 75 meters which ... is quite a lot ... so
we certainly don't want sea level to rise
that much but what are some of the assumptions
that we made in this analysis?
So firstly we assume that ... the ocean is
a box basically, but not a box but we assume
that it doesn't increase its surface area
with radius of the earth.
Absolutely yeah and what happens as we start
to melt the ice on Antarctica, what happens
to the surface area?
I will increase.
It'll increase right what will that do then
to our estimate for how much sea level will
rise?
It will decrease it.
It will decrease it absolutely yeah and so
if we wanted to get a more precise estimate
of that sea level rise can you think of a
mathematical tool or method that we can employ
that would perhaps get us a better estimate?
If something's changing over time what would
what might we do?
You'd have to integrate it.
Yeah I think you'd have to integrate it as
well yep exactly.
What other assumptions did we make?
Well we assume this is the only factor but
we're just saying this is the height based
on the Antarctic
I guess we're assuming this is a kind of average
density of the ice because there's gonna be
a lot of packing of the ice around.
Sure absolutely yeah so the density of the
ice could change especially we know with ice
sheets there's a lot of pressure at the lower
... at the base of ice sheets which really
pack down that ice absolutely, and that will
affect our estimates.
We're also assuming like the temperature of
the water like thermal expansion stuff.
Yeah so what happens with the temperature
of the water and so when the temperature increases
what happens to the volume of the water?
So if it's taking all this like cold ice water
it's going to ... be decreasing in temperature
and the thermal expansion is going to decrease
so not rise by as much as predicted.
Right but let's say then also as well you
have this increase in global temperatures
which is causing the melting and that might
be warming the oceans ... sort of elsewhere,
so then what would happen to the oceans in
that sense?
So that will just cause an expansion and an
increase in height as well.
Right exactly so we would have to balance
those two and actually it's thought that the
warming that's occurring is actually going
to cause quite an increase in sea level even
without any of the melting of glaciers.
Great thank you so much, I'll pass you on
to Roger.
Thanks a lot Jamie so we have time for another
question so ... sort of refresh your brain
and I'm just going to go slightly lower down
on the whiteboard so I'm just going to start
writing underneath the last one.
So this is an entirely different question
so can you see, oh just a second let me get
this straight, right so can you see the line
that I'm drawing?
I can see it after you finish drawing only,
yeah there it is.
It's a thinner line than I expected, let me
just try and increase the thickness, okay
let me try again, okay oh don't worry about
that okay great so I've drawn a vertical line
and these are axes of a graph.
Now we're used to thinking about graphs that
have values on their x-axis and y-axis that's
a sort of conventional graph ... and we call
those cartesian coordinates but this is quite
a different type of graph we're going to draw
so this is a traditional graph that you're
probably very used to, but I'm just going
to draw to the side of that a different graph,
and in this graph we have a point in the centre
still called the origin and the way we plot
points onto this graph is we just have one
linear axis that I'm drawing now can you see
that?
Yep.
And that's called the r axis so one of our
values is this thing called r which describes
the distance from the origin and then the
second axis is an angular axis so it describes
how far around from the vertical line that
I've drawn in angle in degrees how far around
we go and that angular axis is called theta.
So for this graph in order to plot a point
I need two values one is r, the distance from
the origin, and the second is theta, the angle
around that we go, in terms of our distance
from the origin.
Have you come across anything like this before
Jamie?
Yeah I came across this slightly in the end
of ... last year.
Okay ... and you know what this is called?
You don't have to know I'm just trying to
see how...
The polar coordinates?
Yeah these are polar coordinates so if you
get some idea of your understanding of polar
coordinates I'd like you to just plot for
me ... what the line would look like which
satisfies the equation r equals theta.
Okay so a lot here it is all right
So what would happen what will happen to r
as we increase theta for example?
That's a useful way to start thinking about
it.
Right so if they're both zero it will pass
through the origin ... as it increases, you
won't be able to see as in drawing, I'll draw
this in a different colour.
Okay well go ahead yeah if you if you can
figure that out but it's fine to draw it however
you like
As it increases in r it will also increase
in the clockwise direction as theta by I guess
it doesn't really matter what the scale is
on this yeah so ... let me just think you'll
be linear so b
It's useful to think about some other points
so let's say like where will the point fall
... when theta equals like 90 degrees?
So let's say this is 90 units away yeah.
Great and how about when theta is 180 and
so on?
This is I've now realized this is too close
... You can always, the easiest thing might
be to just change the position of that point
yeah
there okay scroll down ... that's about the
whole.
Yep great.
triple will be around here.
Yep great.
and
this is a bit far away now.
Yeah that's fine and then draw the line that
you think what the line would look like connecting
those points?
So it will start to spiral.
Yeah that's great it describes a spiral.
This is really hard to draw on this tablet.
That's all right I mean the main thing is
that you know that it's a spiral and what
will happen as we continue increasing even
beyond the line that you've drawn so far?
Yeah it'll be concentric.
Yeah it'll continue spiralling concentrically.
Just give me a second because I need to plug
my computer in otherwise we'll have a problem,
okay great, all right ... and what so how
would a line that satisfies this equation
differ from the one that you've drawn r equals
theta over two how would that look?
Okay so doing the same thing again just measuring
points let's do red this time.
Okay.
I'll draw within the fortune cookie looking
thing
actually I'll label it as.
You can describe verbally what you think it's
going to look like compared to the other one
if you like.
Okay ... well I think it's better, I think
I can get more if I draw ... there will just
be each point will be twice as close.
Yeah okay so that looks like a tighter spiral.
Yeah.
Okay right now something slightly different
to that I'm just going to share an image with
you so I'm going to share my screen on Teams
now, I can do that.
Okay can you see the image clearly that I'm
sharing with you?
Okay ... I mean what can you see in the image
we'll start just by looking at these two?
It's a couple of spiral shells.
Yeah okay and yeah these are fossil shells
do you know have you come across fossils like
this before?
It doesn't matter too much whether you have
or not it's just useful to discuss what they
are.
Yeah I've seen these before, are these ammonites?
Yeah these are ammonites and they're extinct
sea creatures that lived at the time of the
dinosaurs and these are just the shells of
these animals.
What's the difference, if you were going to
write an equation using r and theta in polar
coordinates, what's the how would you how
would the one on the right differ from the
one on the left?
So it's much looser spiral than the one on
the left so the coefficient on the theta would
be larger than the one on the left.
Okay so this has a larger coefficient multiplying
with theta okay and then I've got a third
one down, here how does that third one, how
would you change the way you draw the graph
for the third one?
Let me think.
Yeah I mean it's useful to start with your
observations what appears different about
this one compared to the others?
Yeah so
ah sorry it's it's quite zoomed in it's hard
to see but ... it doesn't actually start at
a point, it's it's got like a little circle
inside the middle isn't or does it still spiral
in.
How big does this appear on your screen at
the moment?
Maybe like six centimetres, I've not got a
very big screen.
Okay sorry about that
let me see if I can put it on the Miro board
instead so you can probably see that it's
probably currently very small but you can
probably zoom into it more easily okay is
it does it appear larger now?
Yes.
Okay that's great sorry for that hiccup
yeah so you should be able to zoom in on that
as well now.
How does the lower one appear different to
the others?
I think that possibly
maybe it's increasing at a slower rate
Yeah you can taki it that it's spiralling
out at a slower rate, what's your observation
that leads you to that conclusion?
Well ... you can see that from the outer most,
kind of, bit of the shell, I don't know what's
called, ... is relatively thinner than the
other ones I don't know the scale but comparatively
to the centre it's smaller than the outer
shells of the other ones even though it's
gone through more spirals.
Yeah exactly it's gone through more spirals
and it's about the same distance out ... so
there are two ways you could do it we don't
know the sizes of these things we only know
the sizes of the image, one way is it could
be a tighter spiral potentially the other
way is you could just allow the line to go
around more times there are two ways we could
vary that okay.
I'm just entering another image now you should
be able to see and I'm going to make it a
bit bigger, okay so the left hand image is
one of the ammonites and this time it's drawn
rather than a photograph and the key thing
is we can also see what it looks like side
on so it was spiralling around in the plane.
The image to the right of it is just a snail
shell ... and I want you to suggest what's
different about that snail shell and how,
if you were going to add another axis to the
graph, how you might capture the way that
the snail shell is coiling differently to
the ammonite shells?
We're in the ... first section to the top
section they both look pretty similar that's
right so they're both kind of at least in
that plane so the r and theta plane they are
... essentially doing the same thing.
That's right good.
As it is if I look at the other one the lower
snail one, as it is spiralling further and
further it's going further and further left
in the image.
That's right good okay so that's right how
might you modify the polar coordinates system
by adding another axis in order to capture
that variation?
So I guess it well it doesn't affect the other
side so if you added another axis you'd just
say ... the centre of the line or the centre
of like the line of the shell, it looks pretty
linear to me but maybe that's not right, I
would guess it's linear.
Okay that's fine you can say that it might
be linear.
It might be linearly increasing in whatever
direction you're going to call that negative
whatever direction.
Okay I'm just going to draw out our original
axes next to that image
to select the pen tool okay let's draw our
original axes that's r
that's theta where would you put this other
axis and can you have a go at suggesting an
equation that would result in a snail shell
rather than an ammonite shell?
Okay
so I guess I would obviously have light in
this direction but doesn't work because it
kind of overlaps with this so you'd have to
put it going and into the page.
Yep that's fine draw an axis going into the
page
It's not so bad
It's good and you can give that axis a name
if you want whatever name you choose.
Let's call that d for depth.
Okay great d for depth, and then what would
the equation look like?
For the ammonite it was just an equation that
said like r equals theta, what do we have
to do in order to capture the fact that it's
also moving along the d axis?
Yeah so the depth is related to the
I mean well r and theta are related so you
can say it's related to both of them.
Yeah and what does it last as the value of
r increases what happens to d?
Yeah it will just increase let's say linearly.
Yeah okay so go ahead you can just express
t in terms of r or in terms of theta it's
up to you it doesn't matter which.
Do you want to write an equation or like draw
the line or?
Just write the equation for me okay ... so
because we know our r is related to theta
you can just express d in terms of r or in
terms of theta.
So we have r is equal to
theta let's say multiplied by
yeah it's easiest if you just try to express
d in terms of one of these other variables
... Yeah we can say that d is equal to ... negative
kr.
Yeah that's right yeah so it has some linear
relationship with r and ... in this case it
increases as r decreases or decreases as r
increases.
Great all right thanks Jamie so that's everything
we have time to ask you ... but before we
go are there any questions you wanted to ask
us about the course or any other sort of aspect
of studying earth sciences or the process?
Sorry I don't have one in mind.
Okay well that's fine we're not evaluating
whether you have questions for us or not is
your chance if there was anything the student
helpers hadn't clarified or you wanted to
ask in a previous interview but didn't have
a chance.
Okay great well that's everything then it
was really great to meet you ... thanks for
your time and ... it's been really interesting
discussing these science questions.
Yeah thank you very much it was really nice
to meet you.
Thank you.
Thanks bye.
Hi again everyone I hope you enjoyed watching
the video ... you could probably see Jamie
did very well, this is because he's already
a student on our course he's already studied
earth sciences for the past year but as you
could also probably see he didn't know all
of the answers and that's okay.
What really helped during the interview is
that he was able to voice his thought process
and so that allowed us to coach him and help
him along the way and see how he was thinking.
What was really great is that he proposed
ideas and directions and he used what he knew
already and applied it to those unfamiliar
situations which is one of our criteria that
we use.
Yeah that's exactly right in an interview
like that we would be impressed that the applicant
was thinking their way through problems, suggesting
ideas, and calmly working through the issues,
you know occasionally making small mistakes
but being able to pick up with a bit of guidance
and get through to the end.
And really that tells us a wide range of things
including things about the ... applicant's
mathematical capabilities and just general
comfortableness with equations but as well
their sort of broad engagement with science
and especially ... the nature of the earth
and the earth sciences, for example in the
question about ice having some reasonable
idea of how the system works just from a qualitative
perspective in the first place.
Yeah based on the observations that he was
making ... when you make ice cubes for example
so that ability to make observations about
your daily life and about the world around
you.
Yeah so if we had a candidate like that at
interview ... it's likely we would make them
an offer and that they would be a relatively
strong candidate.
Weaker candidates might have more difficulty
proposing ideas or might be able to organize
their equations and thoughts less clearly
and struggle to a greater extent with the
questions.
Stronger candidates might work through more
quickly and make connections more rapidly
but overall that was a very strong sensible
performance, bearing in mind this is one of
our existing students who sat a year of the
course as well, it's very commendable solid
performance