Name: 5 Measurements You Might Not Realize Are Named After Scientists
Uploaded: 2020-03-30T03:39:26.000Z
Duration: 12 min 8 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Like any teacher will tell you, units are important.

Like, saying something is “100 degrees” doesn't mean anything.

Are you talking degrees Fahrenheit, or degrees Celsius, or just degrees of rotation?

Pretty big difference between those things!

Units are a major way we describe the world around us, but in conversation,

they can go by so quickly that we don't give them a second thought.

After all, many units are named after influential scientists.

So by looking at their stories and the discoveries they made,

we can get a sense of how we've learned so much about our universe.

On a different note, we can also get an idea of the kinds of voices that researchers historically valued.

Which means that, demographically, this list might not be a shocker:

It's a bunch of rich, white European men.

Rich, white European men who made some important discoveries.

Every day, millions of people use a temperature scale named after Daniel Gabriel Fahrenheit,

who was born in 1686 in what is now Poland; so probably I pronounced his name wrong.

and it dominated scientific measurements right up until the middle of the 1900s.

So even though using it is something Americans get picked on for,

it's really no surprise that it remains widespread.

But really, “Fahrenheit” wasn't Fahrenheit's biggest contribution to science.

Instead, he stood out because of his thermometers.

Thermometers in the 18th century were glass tubes filled with a liquid that expanded as it warmed up.

Typically, they contained water, oil, or purified alcohol, but those liquids weren't great at that job,

because they tended to freeze or boil at pretty mundane temperatures.

And once that happened, the thermometer was useless.

Fahrenheit improved this system in two big ways.

For one, he made his thermometers using mercury.

Mercury stays liquid across a much wider range of temperatures,

so you could use mercury thermometers in more situations.

The purity of mercury also varied less from place to place, meaning Fahrenheit's thermometers

would behave consistently regardless of where they were made and sold.

Admittedly, a few people had tried mercury thermometers before,

but mercury doesn't change size quite as much as other liquids,

which meant that it was harder to tell when the height changed in the tube.

So Fahrenheit's second improvement was to make his instruments with really thin glass tubes.

Whenever the mercury inside expanded even the tiniest bit, he could tell, and he could measure it.

Fahrenheit was able to make those narrow tubes over and over and over again,

and he could get mercury no matter where he sold them.

So his tools quickly spread all over Europe, as did the scale he invented to go with them.

Eventually, more precise and accurate thermometers were invented,

but the idea to use mercury stuck around, along with what was by then

commonly called “Fahrenheit's scale”, or, as we know it today, Fahrenheit.

The watt is a unit of power, defined as the consumption of one joule of energy in one second.

For reference, one watt is about how much energy two bulbs consume

on an older string of Christmas lights, which is not very much at all.

So it's a little bit of energy, but James Watt, its namesake, was no chump.

He was a Scottish engineer and inventor in the late 1700s and early 1800s.

And his biggest claim to fame was his steam engine.

Kind of like what happened with Fahrenheit and mercury,

Watt did not invent the modern steam engine. That happened in the 1690s.

But he did make some significant improvements to them.

In 1764, he realized that the steam engines of the time wasted a lot of energy.

Steam engines work by boiling liquid water into steam,

which expands and pushes on something like a piston.

Pushing a piston once isn't generally that helpful, so the steam then gets collected, cooled down,

and condensed back into a liquid so that it can re-boil, push again, and repeat the cycle.

Original steam engines used the same chamber for both the heating and the cooling stages.

But Watt realized that constantly changing the chamber's temperature

wasted energy that could have gone into moving the piston.

After all, every time you cooled the chamber down,

you undid the work you had put in to heat it up in the first place.

To fix this problem, Watt designed an engine with separate boiling

and condensing chambers that was far more efficient than other engines of the day.

His engine would let you accomplish way more with the same amount of energy.

Like, if you could only burn a certain amount of coal each day,

you would get more out of it with Watt's design.

The engineer also made lots of tweaks and improvements to his work,

and had plenty of other inventions, too, including a photocopier.

But a better steam engine was his biggest legacy.

And because he did so much to improve how people use energy,

the unit of energy consumption was named after him in 1882.

At first, the ampere might sound less familiar than other units we've talked about so far.

But its nickname might ring more of a bell: the amp. Amps measure electric current;

the amount of electric charge moving past a point in a given length of time.

Cell phones draw one or two amps while they charge,

and each ampere is equal to about six million trillion electrons going by per second.

The ampere is named after André-Marie Ampère,

who was a physicist that worked in France around 1800.

Scientists in Ampère's day were just starting to seriously study electricity,

and they'd already discovered that a current in a wire could affect a compass.

This sounds weird, but it proved that there was

some sort of connection between electricity and magnetism.

And Ampère wanted to understand that connection better.

He sent currents through two parallel wires and found that the wires either attracted

or repelled each other, depending on the direction of flow in each wire.

The wires acted like magnets with north and south poles,

except that Ampère didn't have any magnets in his experiments.

He only had these two wires carrying currents.

Eventually, he realized that current was like a magnet that you could turn on and off.

And today, this idea is used in electromagnets that spin motors

in everything from ceiling fans to car engines.

But this isn't where Ampère's work stopped.

After this, he also discovered a precise relationship between the amount of current

and the strength of the magnetism it produced; a relationship that is today known as “Ampère's Law”.

His research into electromagnetism laid the groundwork

for some of the most important physics in the last two centuries;

work that has affected everything from power generation to computers.