Eureka! 20: Measuring Temperature

Summary

The video script explores the concept of temperature and its measurement. It explains how matter expands when heated and contracts when cooled, affecting our perception of hotness or coldness. The script introduces Anders Celsius, who in 1742, invented the thermometer using mercury's expansion to measure temperature. He set the freezing point of water at 0°C and the boiling point at 100°C, creating a scale to measure the relative speed of molecules, or temperature. The video humorously suggests that the ideal bathwater temperature is 37°C, matching the human body temperature.

Takeaways

• 🌡️ Temperature is a measure of how hot or cold something is.
• 🔥 When matter heats up, its molecules move faster and take up more space, causing expansion.
• ❄️ When matter cools down, its molecules move slower and take up less space, causing contraction.
• 🛀 The human body can't directly measure temperature but can sense differences in hotness or coldness relative to something else.
• 🌡️ Anders Celsius invented a thermometer in 1742 to measure temperature by observing the expansion of mercury in a tube.
• ⚖️ Celsius labeled the freezing point of water as 0°C and the boiling point as 100°C, creating a scale for temperature measurement.
• 🌡️ The thermometer measures the speed of molecules indirectly by measuring the expansion of a liquid like mercury.
• 🏠 A comfortable room temperature is around 20°C, while 30°C is considered too hot and -20°C is too cold.
• 🌡️ The ideal temperature for bath water is about 37°C, which is also the normal body temperature.
• 🚿 The script humorously suggests taking a shower instead of a bath, implying that adjusting the water temperature might be unnecessary in that case.

Q & A

What happens to matter when it gets hot?

When matter gets hot, its molecules move faster and take up more space, causing the solid, liquid, or gas to expand.

What occurs when matter cools down?

When matter gets cold, its molecules move slower and take up less space, leading to the contraction of the solid, liquid, or gas.

How does the human body perceive differences in temperature?

The human body perceives differences in temperature by comparing how hot or cold something is relative to something else, but it may not always agree on the exact degree of hotness or coldness.

What is the significance of Anders Celsius's thermometer?

Anders Celsius's thermometer provided a standardized way to measure temperature by using the expansion of mercury to indicate degrees of hotness or coldness.

What substance did Anders Celsius use in his thermometer?

Anders Celsius used mercury in his thermometer because it expands quite a bit when it gets hot.

What did Anders Celsius label as 0° C on his thermometer?

Anders Celsius labeled the freezing point of water as 0° C on his thermometer.

What point did Celsius mark as 100° C on his thermometer?

Celsius marked the boiling point of water as 100° C on his thermometer.

What is the ideal temperature for human body according to the script?

The ideal temperature for the human body, as per the script, is around 37° C, which is also the normal body temperature.

How can one ensure the bath water is at the right temperature according to the script?

One can ensure the bath water is at the right temperature by adjusting it to 37° C, which is the ideal temperature for human comfort.

What is the term for the device that measures temperature?

The term for the device that measures temperature is a thermometer.

Why might taking a shower be a better option than a bath in the context of the script?

Taking a shower might be a better option because it allows for easier and more immediate adjustment of water temperature to the body's comfort level.

Outlines

00:00

🌡️ Understanding Temperature

The script discusses the concept of temperature and how it relates to the speed of molecules. When matter heats up, its molecules move faster and occupy more space, causing expansion. Conversely, when matter cools, molecules slow down and contract. The script uses the analogy of choosing a bathtub with the ideal temperature to illustrate the difficulty in judging hotness or coldness without a standard reference. It introduces Anders Celsius and his method of measuring temperature using mercury's expansion in a tube, which he calibrated against the freezing and boiling points of water, creating the Celsius temperature scale. The script concludes with the idea that adjusting bath water to 37°C would provide the perfect temperature for a bath, based on the normal human body temperature.

Keywords

💡Matter

Matter refers to anything that has mass and occupies space. In the script, matter is discussed in its three states: solid, liquid, and gas. The concept is central to the video's theme of temperature and expansion, as it explains how matter behaves differently when it gets hot or cold, leading to expansion or contraction.

💡Molecules

Molecules are the tiny particles that make up matter. The script uses the term to describe how the speed of molecules changes with temperature, leading to the expansion or contraction of matter. Molecules moving faster in hot matter take up more space, while slower molecules in cold matter take up less.

💡Temperature

Temperature is a measure of the average kinetic energy of the particles in matter. The script discusses how temperature affects the speed of molecules and, consequently, the size of matter. It's the central theme of the video, as it explains the need for a standardized way to measure hotness or coldness.

💡Expansion

Expansion is the process by which matter increases in volume when heated. The script uses the concept to illustrate how matter, when hot, takes up more space due to the increased speed of its molecules. This is exemplified by the mercury in the thermometer expanding when heated.

💡Contraction

Contraction is the opposite of expansion, where matter decreases in volume when cooled. The script mentions how matter contracts when it gets cold, with molecules moving slower and taking up less space, as seen with the mercury contracting in the thermometer when placed in cold water.

💡Thermometer

A thermometer is an instrument for measuring temperature. The script introduces the invention of the thermometer by Anders Celsius, which uses the expansion of mercury to measure temperature. It's a key tool for understanding the video's message about quantifying temperature.

💡Anders Celsius

Anders Celsius was a Swedish scientist known for his work on temperature measurement. The script highlights his invention of the Celsius temperature scale, which is central to the video's narrative about the standardization of temperature measurement.

💡Celsius Scale

The Celsius Scale is a temperature scale where 0° represents the freezing point of water and 100° represents the boiling point of water. The script explains how Celsius used this scale to measure temperature, which is crucial for understanding the video's theme of temperature measurement.

💡Freezing Point

The freezing point is the temperature at which a liquid turns into a solid. In the script, the freezing point of water is set at 0° Celsius, which is used to calibrate the thermometer and is a fundamental concept in understanding temperature measurement.

💡Boiling Point

The boiling point is the temperature at which a liquid turns into a gas. The script mentions that the boiling point of water is set at 100° Celsius, which, along with the freezing point, helps define the Celsius temperature scale.

💡Body Temperature

Body temperature refers to the internal temperature of a living organism. The script uses the example of human body temperature being around 37° Celsius to illustrate how the thermometer can be used to measure and maintain a comfortable temperature for bathing.

Highlights

Matter expands when heated and contracts when cooled due to changes in molecular motion.

Temperature measurement helps determine whether something is hot or cold.

The human body perceives temperature differences relative to other objects.

Anders Celsius developed a thermometer to measure temperature in 1742.

Celsius used mercury's expansion to measure temperature indirectly.

He set the freezing point of water at 0°C and the boiling point at 100°C.

The Celsius scale was created to measure the relative speeds of molecules.

Comfortable room temperature is around 20°C.

Normal body temperature is approximately 37°C.

The thermometer allows for precise temperature measurement for comfort.

The term 'thermometer' comes from the Greek word for hotness, 'thermos'.

Adjusting bath water to 37°C provides an ideal temperature for bathing.

The narrative humorously suggests taking a shower instead of a bath at the end.

The importance of accurate temperature measurement for various applications is emphasized.

The historical context of temperature measurement is provided.

The relationship between molecular speed and temperature is explained.

The narrative uses a bathtub analogy to explain temperature perception.

The concept of relative temperature perception is introduced.

The narrative discusses the limitations of human perception in judging temperature.

Transcripts

Eureka The Story So Far when matter in

any of its three states gets hot its

molecules go faster and take up more

space and the solid liquid or gas

expands when matter gets cold its

molecules go slower and take up less

space and the solid liquid or gas

contracts and now measuring

temperature can you tell whether

something is hot or

cold in that case decide which of these

three bath tubs you'd like to step into

this

one which is freezing

cold or this

one which is boiling hot or this one

which is neither too hot nor too cold

it's an easy Choice isn't it well go on

step into the middle one feels just a

bit too hot doesn't it try the other

foot oh now it feels a bit too cold well

perhaps judging whether something is hot

or cold isn't so easy after

all this is because the human body can

only notice differences in hotness or

coldness how hot or cold something is in

comparison with something

else but even your own

can't agree about how hot or cold the

water in the middle bathtub

is there must be a better way to measure

degree of hotness or temperature as we

usually

say what do we know about

hotness well when the temperature of

something goes up its molecules go

faster the molecules in the boiling hot

bath water are going too fast for

comfort and the molecules in the

freezing cold bath water

are going too slowly for

Comfort if we could only make sure that

the molecules in the in between bath

water were going at just the right speed

for the human body you could take your

bath but how can we measure their speed

molecules are so tiny we can't even see

them let alone clock how fast they're

going wait a minute there's something

else we know about hotness it not only

causes a speed up of molecules but this

speed up causes matter to expand and so

we could measure molecule speed

indirectly by measuring the effect of

that speed the expansion

itself and that's exactly what a Swedish

scientist by the name of Anders Celsius

did in

1742 he took a liquid that expands quite

a bit when it gets hot Mercury and

poured it into a little tube he then put

the tube into some freezing cold water

and the Mercury contract Ed down to here

he decided to label this freezing point

of water

0°

C next he put the tube into some boiling

hot water and the Mercury expanded up to

here he marked this boiling point of

water 100°

C now we had a means of measuring the

relative speeds of molecules in other

words the relative temperature or degree

of hotness of things comfortable room

temperature is

20° but 30° is a bit too hot and - 20°

is much too cold Celsius could even take

his own

temperature and find it to be about

37° which naturally enough is the ideal

temperature for your bath water normal

body

temperature all you have to do is adjust

the water to

37° and you'll finally be able to take

your bath courtesy Anders Celsius and

his hotness meter or if you prefer the

Greek word for hotness which is thermos

as in Thermos bottle his thermos meter

or

thermometer is your bath water at the

right temperature now oh my

my you should have taken a shower

a