- These are pictures of people who have arrived late
to their exam and have been locked out.
They might've only been a few minutes late,
but this is Brazil's National High School Exam, ENEM.
And at the same time, all across the country,
the exam starts and the gates are locked.
And by the looks of this, if you're not there on time,
they're really not letting you in.
This footage is heartbreaking
because the exam is so important.
It only takes place once per year.
And it is used for entry into many
of the Brazilian universities.
In 2016, there were 8.6 million candidates,
which makes it the second largest exam in the world
behind China's Gaokao.
It doesn't come without controversy.
This year, the exam took place despite the pandemic
causing extensive school closures and hardships
for many students, in fact, this year about 50%
of registered candidates failed to show up.
And only a month ago, 37 workers resigned
from the agency that prepares the exam amidst claims
of political censorship with some of the questions.
Thank you to everyone who requested
I take a look at this exam, some have even be waiting
two years for me to get around to it.
One person said they thought it was harder than the SAT,
but easier than exams in Asian countries.
And I do tend to agree with that.
At least the countries that I've looked at
in previous videos, I've got a copy of the 2021 exam
here to take a look at, in total,
there are 180 questions taken over two days,
lasting a total of 10 and a half hours, which is huge.
It covers languages, social science,
and natural science and mathematics.
I've got here, the natural science and math paper.
For this, there are 45 questions on the sciences,
that's chemistry, physics, and biology,
and then another 45 questions for math.
For this paper, you would have five hours.
So that works out to just over three minutes per question,
the questions are all multi choice,
but if you take a look at them,
they're extremely wordy and very long in sort of set up.
Now, this is all in Portuguese,
but I've also run the exam through a translator.
And here's the English version.
Some things have been lost in translation,
but I think it gives a pretty good idea
of what the exam's about.
You might also notice that some of the questions
are pretty visual, this one here is
from the pretty famous comic Calvin and Hobbes,
and it looks like the boy is complaining that it's hot,
but the tiger says that what really bothers him
is the humidity.
The question then asks why that might be the case
with the answer being that sweat has greater difficulty
in evaporating from the body when it's humid,
let's have a go at question 115.
Again, there's a really long lead up to even know
what the question is about, but it says that,
"In autumn, the leaves and trees change color
from green to shades of yellow, brown, orange, and red.
The green color of the leaves
is due to the pigment chlorophyll
in plants with deciduous leaves,
the production of chlorophyll decreases
and the green tone fades, allowing other pigments,
such as carotene, with a yellow orange coloration.
And anthocyanin with a reddish tone
to dominate the tone of the leaves.
The observed coloration is due to the interaction
of these pigments with solar radiation.
As shown in the absorption spectrum,
the chlorophyll molecules absorb solar radiation
in the blue and red regions, so the light reflected
by the leaves lacks these two tones
and we see them as green color,
anthocyanins absorb light from the blue to the green.
So in this case, the light reflected by the leaves
contains the complimentary colors,
which are red and orange."
All of that is to ask, "In what range
of the visible spectrum do the carotenes absorb the most?"
What they've told us about the carotenes
is that those leaves are higher yellow-orange in color.
So if we look at the little color wheel we've got yellow
and orange here,
the complementary colors to those are violet and blue.
So those are the correct answer, A.
Whilst these questions may not be as rigorous
as some of the other ones we've seen.
You still need a very broad base of knowledge
because you're doing everything from writing essays
to answering these questions about the planets.
You might even learn a thing or two
while you're in the exam.
Here's question 135, it tells us about the memetic octopus,
which has very curious color patterns and behaviors.
It often changes the orientation of its tentacles,
resembling some other animals.
Here you can see the octopus mimicking a lure fish.
That's what a lure fish looks like,
here it is mimicking a lionfish
and here it is mimicking a sea snake.
The question asks from an evolutionary point of view,
the capacity presented was established
because octopuses what?
With the correct answer being because they survived
the selective pressures with these behaviors.
Here's the start of the math section.
Again, very wordy, even for math questions,
the amount of reading that's involved
means the test can become very tiring to take,
especially after five hours of this.
Here's a question that jumps out as being interesting.
It looks like a tesseract, a four-dimensional cube.
The questions says, "Many toys that are often found
in public squares and parks are shaped like two
and three dimensional geometric figures.
A company was hired to develop a new form of toy.
The proposal presented by the company was a structure
formed only by metal rods connected to each other
as shown in the figure."
But it turns out you don't actually need to know anything
about four dimensional cubes,
because the question just asks,
"Based on the proposal presented,
how many plane geometric figures of each type
are formed by the union of the rods?"
So basically take a good look at this picture
and see how many shapes are in there.
Luckily, the first answer turns out to be the correct one.
See if you can spot 12 isosceles trapezoids and 12 squares.
Here, we have the cutest little mug I've ever seen
in an exam with the question asking us
to find the volume of the shape here.
Now this is actually called a truncated cone
or a frustum, and there is a formula
for finding the volume of one of these.
So if you show up with that memorized,
it's probably gonna be a bit easier for you,
but if you're left high and dry and don't know the formula,
it's not impossible to work it out from scratch as well.
What you do is you imagine extending this
to become a complete cone,
and then you find the volume of this large cone
and subtract off the volume of this little cone here,
doing that and using three as an approximation for pie,
you'll get 732 as the answer.
They have this very intricate
and very Brazilian question here
about all of the football teams.
The question had been asking something
about how many combinations you could make
if you arranged all of these team logos on a shelf
with a set of intricate conditions.
But in the end, this question was nullified
because I think they couldn't totally agree
on what the correct answer would be.
So, all this work kind of was for nothing.
The second to last question, 179,
looks best formatted in the Portuguese version.
And it's about the golden ratio.
It talks about how, if you have a line divided
into two parts, then those two parts
will be in golden proportion when the ratio
between the hole and the largest one of the paths
is the same as the ratio between the larger part
and the smaller part.
You can also find the golden ratio
as the solution to the equation,
phi squared is equal to phi plus one,
and that becomes the first element of this table here.
It then goes on to say that phi cubed
can be found as two phi plus one.
And there are similar relations for the rest of the powers.
The question is defined,
what would phi to the seven be equal to.
I guess you don't need to understand the context too much,
but if you just look at the table
and try to find a pattern that will give you
this missing box, you might notice the Fibonacci numbers.
That the coefficient out here in front of the phi
is the previous two added together,
five plus three gives you eight,
two plus three gives you five, one plus two gives you three.
So with that we'd have eight plus five is 13.
And the Fibonacci numbers are also in the second term.
One, one, two, three, five, eight, the golden ratio
and the Fibonacci numbers are interlinked with each other
in so many weird ways.
But if you didn't already know that,
then good luck noticing it for yourself
during the pressure of the exam.
The very last question is basically an essay
that describes this sculpture here in Brussels
called the Atomium.
It tries to describe that the whole thing
is a giant cube tilted onto one vertex,
which is touching the ground.
And you can take an elevator straight up from this sphere
through the middle one, through to one at the top,
I found this a really hard to visualize given
that you can't really see half of it in this picture here,
but the questions says that we have a visitor
who moves around the interior of the sculpture,
always following the shortest path between vertices
and passing all inches and all diagonals of the cube.
They want to know what the path of this traveler
would look like if it was projected down onto the ground.
The question does say that there are
nine of these metal spheres.
And since you are traveling to each one of them,
you would expect, I guess,
nine distinct points on the projection.
Although this first part of the journey up the elevator
from the ground, to the middle,
to the top, all three of those spheres are in the same line.
So, would only appear as one, in total then
we would expect seven dots on the projection.
One, two, three, four, five, six, seven,
means that E is the correct answer here.
It's also got the right amount of symmetry compared to C,
which would be more of a rectangular sculpture.
I happened to have seen, a bit of a Brazilian TV show
called "3%" and it's this futuristic dystopia
where most people live in this impoverished inland.
And when everyone is 20 years old,
they get a single opportunity to complete
something called the process, which is essentially
a big test and only 3% of candidates pass this test
and get to go and live luxurious, affluent lives,
in this distant offshore society.
In the show passing the process
is basically your only chance at a good life.
And so people spend their entire lives up until they're 20
preparing for this one shot, it's a fictional story
that speaks to a lot more social issues like inequality,
but I can't help, but notice a lot of parallels
between that show and this exam.
It's this idea that you spend so much of your life
preparing for one single test,
which can determine so much of your future.
This article I found from inside higher ed,
spoke about how in 2016, they were 8 million students
who were competing for approximately 250,000 places
in the federal universities.
And when you crunch the numbers on this,
it works out to around 3%, the same number
that make it through in the show.
In both cases, whether you're talking about
the physical process that they go through on TV
or this intellectual exam, both are supposed
to give an equal chance to everyone,
they're supposed to admit the 3% most deserving candidates.
But of course, there's always issues associated
with that goal for one in education, private coaching,
and access to better schools and teachers,
will always be easier for people that start off
from a more privileged position.
But for many countries not just Brazil,
where you've got huge numbers of students applying
for relatively small amount of places,
then you need to figure out some way of doing things.
And these giant exams seem to be currently
one of the best strategies that we have,
I suppose, as a student,
you just have to do the best you can to be prepared
and to not be late.
I'd like to thank Brilliant for sponsoring this video.
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These are some clips from their recently
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So, I hope that whoever receives it,
enjoys learning something new, a big thank you to Brilliant
and thank you to my Patreon supporters,
for making this video possible.
A special shout out to today's rather dog looking Patreon,
cat of the day, Pepper.
(gentle music)