Freezing and melting points

Freezing and melting points

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Further Resources
This task is about freezing and melting points of some liquids.

Question

Not everything will freeze when left in a freezer! The temperature inside a freezer is ¯4°C. 
Below is a table of the melting points for three substances which are all liquids at room temperature.
 
Substance Melting point (°C)
methylated spirits (meths)
(mostly ethanol)
 ¯114
petrol (mostly octane)
 ¯56.8
ethanoic acid

(used to make vinegar)

  16.7
 
Three 500 mL bottles are each half-filled with the liquids and were placed in a freezer overnight.
 
a)   Which liquid(s) would be frozen the next day? 

    • Methylated spirits

    • Petrol

    • Ethanoic acid

Question 1Change answer

b) Explain, in terms of particles, what has happened when a liquid has frozen.

Question 1Change answer

c)   Will the level in the frozen bottle(s) be higher or lower than before?
HigherLower
Explain your answer in terms of the particles.
Task administration: 
This task can be completed online or with pencil and paper.
Level:
5
Curriculum info: 
Science, Knowledge, Material World
Keywords: 
changes, particle nature of matter, solid, liquid, changes of state, table interpretation, freezing
Description of task: 
Using provided data students decide which of three liquids would freeze if placed in a freezer. Students explain what happens to particles when they freeze and how the level changes due to freezing.
Curriculum Links: 
Science capabilities

The capabilities focus is brought about by the conversations you have and the questions you ask.

Capability: Use evidence

This resource provides opportunities to discuss using information from a table to make inferences about freezing and melting
  • and from their developing science understandings to help explain aspects of the particle theory.
Answers/responses: 
  

Y9 (08/1997)

Y10 (08/1997)
a)   Ethanoic acid. easy easy
b)   The particles get closer together/
slow down.		 very difficult difficult
c) i)
ii)		 Lower.
The particles in a solid are closer together than those in a liquid so the solid takes up less space (water is the exception, not the rule).		 very difficult difficult