Teaching first-year physics here has
given me a much greater appreciation for
how amazing certain things are that go
on in the real world - and they can be
everyday things, literally like riding a
bicycle.
And actually being able to think about
them, ask questions about them, the
puzzles that we meet in everyday life,
those are the things that lecturing this
course in particular has given me better
insight into. Because until you actually
start teaching a subject only then that
you really start to understand it and
understand all the nuances of it. I'm
Lisa Jardine-Wright,
I'm the educational outreach officer at
the Cavendish laboratory here in
Cambridge and the Cavendish laboratory
is our Department of Physics. My PhD's in
Astrophysics so I did galaxy formation
simulations from the Big Bang to the
present day for my PhD and for my
postdoctoral research. And that was at
the Institute of astronomy here in
Cambridge. Now I'm a Director of Studies at
Churchill College, I'm a tutor there, and
I lecture special relativity and
rotational mechanics for first years
doing the Natural Sciences course. We have
students from all over the world, all
walks of life, all different interests, so,
because of the Natural Science Tripos
here, there are students that are
learning Physics, Chemistry and Biology
all at the same time, so they may not be
wanting to specialise in Physics. So when
you're lecturing you have a huge wealth
of diversity. I think the other thing that I
would say is that they're... the
thoughtfulness. Those students that
really have a passion for the subject,
really listen in the lecture, they really
come and they think, and they ask you
really insightful questions at the end. And for me, as a lecturer, that's one of
the challenges but also one of the
benefits as well. [To student] So in this equation
it's always that this center of mass is
referring to the body that you're
interested. So it's only when you're moving the axis
with respect to the center of mass
of that body, not this one that is a
combination of all of the others.
Is that alright?
Student: Mmhmm, yeah, it's fine.
Ok. Good.
So one thing that's interesting 
about teaching this course is
in Natural Sciences in the first year in
Physics we have 400 students so it's
quite a different different environment from their environment at school.
So we try to be interactive.
I have something to show you for our breather
today but before we do that I want to do
a demonstration to see whether you have,
through looking at that example,
gathered some intuition about what's
going on. So I have three objects here.
They are all the same mass and they are
all the same radius. I have 
a solid sphere,
a solid cylinder -
- not quite but it's pretty much a good approximation to a solid cylinder -
and a hollow cylinder
I'm going to start them at the same
point on the ramp
and I want you to predict - I'm going to
ask for a show of hands - which is going
to reach the bottom first. Who thinks the
solid sphere?
And quite a few of you are
sitting on the fence. That's fine.
Ok. Right, so I'm going to do this twice
because it's not easy to release them at
the same time.
Three. Two. One.
OK. So the
sphere was the clear winner, I think.
I'm going to swop it around: hollow, solid, sphere.
That was bound to happen...
So the hollow cylinder was last.
The solid cylinder was second, and the sphere
was first.
So I will leave you again, as
an exercise between now and next time, to
think about why that happened.
But the most important things for me,
I think, is that they are willing to make
mistakes, so I positively encourage them
that solving problems is not about the
answer, it's about the journey that they
take along the way. And it's about
learning through making mistakes rather
than trying to get everything right all
the time. And that, again, is quite a
contrast from coming from school.
Here, learning is about making mistakes and
learning from those mistakes.
dumar goals
