probably, well, that I love the end of the world.

I've made a lot of videos about it on Vsauce 3 like

Could You Be The Last Of Us? Could You Survive A Fallout? What If The World Ended?

And then one recently about what if everyone were taken over by parasites?

So this episode is all about different types of disasters that can occur.

And I'm going to give you safe ways to simulate them but just in case you find yourself in a real life one

Well there's disasterpreparer.com/websites.

And that could help. It's a website full of more websites that show you what you could do in case of an emergency.

It's a DONG, something you could do online now guys.

On the Habitable Planet you can learn through lessons and their corresponding simulations.

I did the Disease Lab which helps you visualize and understand how pandemics like the Spanish

Influenza of 1918 occur and affect populations. It infected around 500 million people worldwide

and killed an estimated 50 to 100 million. That's anywhere from 3 to 5% of the global

population at the time which was thought to be around 1.8 or 1.9 billion. If we go further

back in time to The Black Death, well that killed an estimated 450 million people during the 14th century.

Of course this simulation can't possibly show the kind of devastation and grief caused

by a massive pandemic like one of those but it does give you an idea of just how quickly diseases

can spread. Pick through four diseases…well, made up diseases based on real ones. Like

Kold with a K or the Neasles instead of measles. Not only does it imitate the name but it even

shares the measles 90% transmission rate and the fact that it's typically contagious

4 days before a rash appears and 4 days after. You can also choose the degree

of population mixing which is when migrants of different origins come in contact with

one another. If you run the simulation it will automatically go for 100 days. But there's

value in going step by step because you can see the spread of illness at work and calculate

it yourself to see if it fits what's typical for that disease. For example, each contagious

dot has eight neighbors. Divide the number of newly red neighbors by 8

to see that it's pretty close to that

90% transmission rate. If you keep going some dots disappear completely and these are the

ones that have died.

Of course some disasters would occur with or without the presence of humans, like hurricanes.

On create-a-cane your job is to set the ideal conditions for its formation. If you wanna

be a pro before you even get into it you can read up on them first with this page. There

are pretty cool facts like how the term hurricane only refers to the large storms that form

over the Atlantic or eastern Pacific. In fact they all have different names depending on

where they are from so it could be a typhoon, cyclone, severe tropical cyclone or severe

cyclonic storm. Whichever one it is, it still requires the same conditions to form. The first is

that there has to be warm ocean water that's at least 80 degrees Fahrenheit and about 165

feet below the surface. This contributes to warm moist air forming above the surface.

Since warm air rises it leaves the surface and creates an area with fewer air molecules

per unit. This lower density causes a low pressure zone which just means there is less

force distributed over the area. The surrounding air has a higher pressure and pushes in to

the low-pressure zone. This new air warms and rises and the surrounding air

swirls in to take its place. These colliding air pressures are what cause those strong

winds. And then there are other factors of course such as wind direction and wind strength

and distance from the equator at formation. But I don't wanna ruin the experience for

you. So you should definitely check this out yourself and explore on your

own. If you do need some help, there are question marks that can give you some guidance. Speaking of strong

winds you can also

Experience the formation of a tornado. Unlike hurricanes, tornadoes form over land and their

winds get much faster. On this simulation you are guided through the ingredients for

a perfect tornado, the storm formation, and at the end you can watch the funnel form.

Many funnel clouds do not actually touch the ground and cannot be defined as tornadoes.

It's definitely cool to see because they're not always visible at this stage in real life.

And also you probably don't want to get that close to one. A category 5 hurricane,

the strongest it can get rarely goes above 195 mph but tornadoes have gotten up to about

300 mph. However, hurricanes can cause more widespread damage due to their size and duration.

They are measured by the Saffir-Simpson Hurricane Scale and Tornadoes by the F-scale. Both categorize

the storms based on their wind speed. Since tornadoes are so strong they would probably

destroy any measuring device, their wind speed is actually just an estimate based on the

amount of damage inflicted.

Now disasters like this can obviously affect the population and sometimes it's hard to Imagine

The Population of Tomorrow. This website predicts age distribution as well as population size depending

on a variety of factors. They will change based on the geographical zone selected. For

example, population growth in the United States is negative since it actually has a sub-replacement

fertility rate of only 1.89 children born per woman. This is the rate that needs to be sustained

for each new generation to be less populous than the subsequent one. But let's change it to

Egypt where the average number of children born per woman is 3.16 and the growth is pretty

fast. During that Flu pandemic in 1918, average life expectancy in the United

States dropped 12 years. So let's say that happened in 2018. Decrease it by 12 and watch

how the population slows down. This is probably intuitive since the death rate is slowing

while the birth rate has been kept constant. But it's still interesting to watch how

that might have looked 100 years ago.

Population growth can get complex with all these factors but predictions can be

made using complex mathematics. To figure out the rate of change of population you can

use something called differential equations. These can also be applied to predict things

like chemical reactions and economic trends. But what are differential equations?

Well, Brilliant.org has a whole course on them with quizzes and it is awesome. Let's go through one

of the questions. Here is an example of a differential equation.

A solution is a function y(x) whose derivative is 6xy. We'll see in the next chapter how

to find such functions. For now, we can whether a function is a solution by differentiating

and seeing whether the equation is satisfied. Which of the following is a solution to this

equation? y=e^3x². CORRECT.

Brilliant was nice enough to sponsor this episode and their site is incredible

It allows you to test your knowledge in subjects like math and science

and it really aligns with Vsauce's mission perfectly so if you want

to continue expanding your knowledge sign up with the link at the top of the description

for 20% off an annual subscription. But, only the first 36 of you will get it so I would recommend going and clicking that link.

Alright I'm gonna go make this entire studio disaster proof...uhh...and as always, thanks for watching.

uhhhh okay.