Freezing salt water

Freezing salt water

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Further Resources
This task is about planning a fair test.

Question 1Change answer

Plan a fair test to find out if dissolving table salt in water will affect the time it takes for the salt solution to freeze. 

Plan your fair test using these three different amounts of table salt: 5 g, 10 g and 15 g. 

You will need to think about:

  • What you would need to keep the same.
  • What measurements you would take.
  • How many trials you would do.
  • Whether you need a control.
Task administration: 
This task can be completed with pencil and paper or online.
Level:
5
Curriculum info: 
Science, Investigating in science, Material World
Key Competencies: 
Thinking
Keywords: 
changes of matter, freezing, fair testing, planning investigations
Description of task: 
Task: Plan a fair test to see if adding salt water to water affects how long it takes to freeze. Assessment focus: managing variables.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
Capability: Gather and interpret data
This resource provides opportunities to discuss making decisions about the best way to collect data to answer a question.
Science capability: Gather and interpret data (TKI)
 
Science capabilities: 
Gather and interpret data
Answers/responses: 
  Y10 (06/1998)
Any 5 of:

  • Using the same amount of water each time.
  • Using identical containers.
  • Placing each trial in a consistent and appropriate location, i.e., the same position in the freezer.
  • Checking freezing at consistent and appropriate intervals.
  • Using a control container with no salt.
  • Using repeat trials.
  • Other plausible points.
 5 correct – very difficult

4 correct – difficult

3 correct – moderate

2 correct – easy

1 correct – easy