I want to talk about Khan Academy if you
haven't heard of it you should
definitely check it out one guy Sal Khan
has made thousands of videos over 2200
at the moment on everything from math to
history and also quite a few videos
about science and there are a lot of
things to love about Khan Academy first
of all everything is freely available
through YouTube and Khan's goal is to
improve the education for all students
and he is an exceptional teacher an
absolutely fantastic speaker he also
emphasizes mastery which i think is very
important so students in the program can
only move on after completing 10
questions in a row correctly and he's
also developed some activities and
software and he's working with schools
to try to humanize the classroom to try
to help improve the quality of student
teacher time and he's pushing the
learning well beyond the video area but
I want to put that work aside for a
moment and just focus on the millions of
viewers who watch his science videos
online
you see I'm skeptical that they actually
promote some meaningful learning and
that's not just a comment about Khan's
videos but a comment on science videos
in general so let me explain that
skepticism I wrote my PhD thesis on how
to create films to teach science
specifically physics in a typical study
students access to a website where they
took a multiple-choice pretest the
questions were something like consider a
basketball player shooting from the
free-throw line after the ball leaves
his hand the force on the ball is a
upwards and constant B upwards and
decreasing C downwards and constant D
downwards and decreasing or E
to the path of the ball take a minute to
think about which answer you would pick
and what you think most other people
would pick after the pretest students
were randomly assigned to see one of
several online videos the videos
contained correct answers to many of the
pretest questions for example here is a
clip now we'll consider a case where
gravitational force is the only force
acting on an object while a juggling
ball is in the air we'll ignore air
resistance because it's so small only
one force acts on the ball throughout
its flight this is the force of gravity
which is constant and downwards gravity
accelerates the ball in the downwards
direction after being thrown up a ball
travels slower and slower upwards its
velocity goes through zero and then it
speeds up in the downward direction the
whole time the ball is accelerating
downwards then it meets the jugglers
hand immediately after watching the
roughly 10-minute video the students
took exactly the same test I also
interviewed some students to see what
they thought of the video the most
common comments were that it was clear
concise and easy to understand the
students also increased their confidence
in the correctness of their answers
compared to the pretest so what about
how much they learned on the pretest the
average score was 6.0 out of 26 and
after the video the average was 6.3 what
was going on I dug deep in interviews to
find out it turned out students did not
even correctly remember what was
presented in the video that they had
seen a few minutes earlier one recalled
in the video it said the ball is slowly
decreasing in force so therefore it
stops at one point and then comes down
what was worse another told me it wasn't
that hard to pay attention to because I
knew already what she was talking about
I hadn't told him about this six out of
26 yet so I was listening but I wasn't
really paying at most attention what can
be done about this
perhaps videos are just too passive a
medium to attract attention for
ten minutes even when you know you're
being interviewed after but I see the
problem a different way typically we
think of education as informing students
about things they are not aware of like
the French Revolution for example with
science presents a different challenge
it is not that students know nothing
about it but that they already have
plenty of ideas most of which are
unfortunately wrong scientifically
speaking they don't pay attention
because they think they know it and then
when asked what they saw they falsely
remember their own ideas as what was
presented is there a way to overcome
this well I thought students might pay
more attention and be able to understand
if their ideas were presented in the
video so one of the other videos
involved an actor pretending to be a
student with the most common
misconceptions which were Illustrated
can you tell me what happens when a
single wall goes around one well Luke's
hand gives the ball of force that drives
it upwards against gravity but as it
goes up this force gradually dies away
until at the very top it perfectly
balances gravity and then gravity wins
or the ball falls down he then discussed
with the other dialogue participant why
the misconception didn't work and how
the scientific idea differed in
interviews with students who watched
this video no one used the words clear
concise or easy to understand most often
they said it was confusing but on the
post-test the average score nearly
doubled to 11 out of 26 when asked to
rate how much mental effort they
invested in watching the videos students
who saw the dialogue with misconceptions
averaged a whole point higher than those
who saw the explanation without
misconceptions and it seems like it
worked that increased mental effort
translated into more learning so with
the veritasium films I always try to
start with the misconceptions how long
does it take for the earth to go around
the Sun well I died obviously that is
this is representing the earth again and
this represents what do you think yes
how far apart are they what rough leg
roughly
is the following statement true or false
humans lived at the same time as
dinosaurs I'll say true we really have
to tackle these misconceptions somehow
it seems if you just present the correct
information five things happen number
one students think they know it too they
don't pay their utmost attention three
they don't recognise that what is
presented is different to what they're
already thinking and four they don't
learn a thing and finally five perhaps
most troubling ly they get more
confident in the ideas they were
thinking before and this is a vicious
cycle that we have to find a way to
break in order to have effective science
education so the Khan videos are amazing
and definitely a valuable resource for
science educators and perhaps people
looking for a bit of review but for
those who are just starting to learn
science I question whether it's going to
be that valuable because it doesn't
really question their misconceptions
may the other person take one day to get
around the Sun thanks for year