3.3 Phase changes

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

Chapter 3.3 Phase changes

Schedule for this lesson

Explanation about the new paragraph

Making question in the workbook/on your laptop

Discussing questions

Recapping

Learning objectives

You can name the six phase changes that substances can undergo

You can describe how the phase transitions of water play a key role in all kinds of weather phenomena

You can use the particle model to explain why temperature plays a key role in melting and evaporation

Last time we talked about...

Temperature

How are we able to measure the temperature?

And do we remember which unit(s) we use for temperature?

Phase transitions 

As we know, weather can change suddenly

A day can start sunny, but end up with a thunderstorm

Phase transitions 

And so do substances!

When water freezes or melts it is known as a phase transition 

A substance transitions depending on the temperature

Phase transitions 

There are six phase transitions 

We will walk through these transitions with examples and pictures

Freezing/solidification liquid->solid

When water freezes it turns into ice

The term solidifying is also used, but for things that turn solid at temperatures above 0 degrees Celsius like candle wax

Melting solid->liquid

When the temperature rises, the solid ice will turn into a liquid again

Evaporation liquid->gas

Over time, when it is warm enough, water can turn into invisable water vapour

Condensation gas->liquid

But when warm air cools down and meets a cold object, water vapour condenses out and turns water vapour into visable water

Deposition gas->solid

When the temperature drops below 0 degree Celsius, water vapour turns into solid ice

Sublimation solid->gas

Snow will slowely get thinner, this is because ice turns into water vapour when the air is cold and dry

But there are substances that can turn from a solid to a gas a lot faster

Both processes are called sublimation

https://www.youtube.com/watch?v=8Gj8dr6AsYg

Phase transitions in the particle model

We are going to look at the particle model again. This time we will look at how to movement of the molecules change depending on the temperature.

https://phet.colorado.edu/sims/html/states-of-matter-basics/latest/states-of-matter-basics_en.html

Making questions 3.3

Make the following questions: 1, 2, 3, 4, 6, 7, 8, 9 and 10

Done? take a look at the extra questions

Discussing questions 3.3

Question 1

• Condensation
• Evaporation
• Deposition
• Sublimation
• Condensation

Discussing questions 3.3

Question 2

• They are similar because the phase transitions from liquid to solid

• They are different because freezing happens at 0 degree Celsius or lower, while solidifying could happen at higher temperatures

Discussing questions 3.3

Question 6

• The temperature indoors in higher than outdoors

• The water droplets are water vapour turning into a liquid because of the temperature change (coming from the air outside)

• Condensation

What did we learn today?

In today's lesson we talked about the different phase transitions 

What did we learn today?

And how temperature changes the way the molecules move in the particle model

End of the lesson