3.2 Temperature

• Natuurkunde / Scheikunde
• Middelbare school
• havo, vwo
• Leerjaar 2

Chapter 3.2 Temperature

Schedule for this lesson

Explanation about the new paragraph

Making question in the workbook

Recapping the last 2 paragraphs

Learning objectives

You can describe how you can measure the temperature of te air around you

You can list the parts of a liquid thermometer 

You can explain how a liquid thermometer works

You can describe a digital thermometer

You can explain what the measurment range of a digital thermometer is

You can give a thermometer a graduated scale in degrees Celsius using the melting point of ice and the boiling point of water (experiment?)

Measuring the temperature 

Your perceptions of heat and cold are not that reliable when it comes to measuring temperatures

When your fingers are cold things could feel warmer than they really are

And when cycling through the wind, it seems a lot colder than it really is, even though the temperature stays the same

Measuring the temperature 

A thermometer lets you measure the temperature 

of the air around you

This gives the temperature a value that is the same for everyone 

So one might think it is really cold, while someone else thinks it's nice and fresh outside

Measuring the temperature 

If you hang a thermometer directly in the sun, its shows a higher

temperature than the outside air (just like how our skin feels 

warmer when we sit in the sun)

When a cloud moves in front of the sun, the temperature will fall

A thermometer that in hung up in the sun can not give the right value for the air temperature

Measuring the temperature 

This is why meteorologists hang their thermometers

up 1,5 m above the ground

They have these weather station huts with open walls so the wind can pass through 

The liquid thermometer

A well-know type of thermometer is the liquid thermometer which consist of 3 parts

The liquid thermometer

The reservoir and part of the riser capillary are filled with a liquid (this liquid is alcohol with an added dye in most thermometers)

The liquid thermometer

When the temperature increases, the liquid in the reservoir expands. This will push the level of liquid in the cappilary tube up.

When the temperature decreases, the liquid contracts and the liquid level falls

The liquid thermometer

You read of the temperature by comparing the height of the liquid in the capillary tube against the graduated scale next to it

The difference between the highest and lowest temperature that can be measured is known as the measurement range

The liquid thermometer

Most of the thermometers we use in our daily life have the temperature measured in degrees Celsius 

There are a few different units in which temperature can be measured, do you maybe know one of them?

Kelvin

Kelvin (K) is a bit of a weird unit, but the unit we use most to define temperature in physics 

We are able to convert the temperature in Celsius to Kelvin

0 degrees Celsius = 273 Kelvin

20 degrees Celsius = 293 Kelvin

-10 degrees Celsius = 263 Kelvin

Kelvin

Kelvin is a unit which has an absolute zero

Which means it can´t get any lower than 0

The digital thermometer

Digital thermometers use a smaller scale to measure temperatures

The digital thermometers you use when you 

are sick don´t need to measure temperatures 

below 35 or above 43 degrees celsius

The digital thermometer

While other digital thermometers could have different ranges

Making question 3.2

Make the following questions: 1, 2, 3, 4, 5, 6 and 7

What did we learn today?

In today's lesson we talked about temperature

How we all feel temperature differently and need a thermometer to know what the temperature really what

What did we learn today?

We talked about different kinds of thermometers and their parts

And we know what Kelvin is

Small recap

What are the 3 phases in which a substance can occur?

• Solid
• Liquid
• Gas

Small recap

Which phase do we see in the picture below?

Small recap

Which phase do we see in the picture below?

Small recap

According to the particle model, how are the molecules moving in a solid substance?

Small recap

According to the particle model, how are the molecules moving in a solid substance?

Small recap

How do we measure the temperature outside?

Small recap

How does a liquid themometer work?

End of the lesson