Fair TestingPresenters: Maria Barrett & Jodi-Ann Gulley

Science & Engineering FacultyQueensland University of Technology (QUT)

Scope

• Fair testing – life skills focus :– ACARA – Science Inquiry Skills focus (also SHE – not

covered in this session)– Problem-based learning– Inquiry-based learning

• Recognises variations between reporting formats – The ‘scientific method’ is not covered in full in this session

• Session will benefit beginning teachers and those seeking more information on fair testing as a process and skill.

What is fair testing?

Fair testing is a way to find the answer to a researchable question and know that the answer is correct.

It helps us to be sure of the cause of something.

Fair testing• Change one thing• Measure one thing*• Keep all other things

the same

Doing this means we can tell what causes the change.

* Measure can also include observe one thing.

Fair testing

• The thing we are changing is called an independent variable (changed by the scientist conducting the test)

• The thing we are measuring is called the dependent variable – This is because the result depends on the thing we

are changing• The things kept the same are the controlled

variables

Example 1 Sherbet Fizz(ACARA Chemical Sciences – Year 6*)

Step 1: the research questionWe know that sherbet fizzes when put in our mouth

– but...What question do we want to answer?

Q: What sherbet ingredients react to cause the fizzing?

Note: Those teachers who use Primary Connections may have used a variation of this experiment in the ‘Change Detectives’ unit.

Step 2: the hypothesis

• An educated guess about how things work

• An easy way to remember:If ......[I do this]....., then .....[this will happen]*.If I mix [different combinations of sherbet ingredients] with water, then I can find out which ones cause sherbet to fizz.

• Needs to be worded so that it can be tested by your experiment

* A ‘because’ statement may be added here to determine student prior understanding and reasoning, and for development of argumentation skills. A ‘because’ statement is not used in secondary school contexts when writing hypotheses.

Step 3: test the hypothesis

• How will you answer the question?

• Design and conduct an experiment using fair testing principles.

• Devise method:– Mix ingredients together– Add water– Watch for fizz

Sherbet testing

• First measure out all the ingredients into the testing tray in a logical order– This prevents contamination (using clean, dry sticks)– We can compare all results at the same time – there

may be some bubbles but only one should fizz up– Make sure this includes testing the ingredients on

their own (control)• Then add the water and watch for fizzing

Icing sugar & citric acid

Icing sugar & bicarb soda

Icing sugar & jelly crystals

Icing sugar

Jelly crystals & citric acid

Jelly crystals & bicarb soda

Jelly crystals

Bicarb soda & citric acid

Bicarb soda

Citric acid

How do I know I am right?

• Fair testing!– Test combinations of ingredients

(independent variable) • Test each ingredient• Test pairs of ingredients

– Watch for fizz (the dependent variable)– Keep all other things the same

(controlled variable)

Example 2 WaterWorks(ACARA Chemical Sciences – Year 7*)

Step 1: the research question

Water filtration is needed to make water safe to drink. You are supplied with a dirty water sample and different filter materials.

What research question do you want to answer?

How will you answer the question?

Conduct an experiment– Select different filtering materials to test– Fill each column with one of the filter materials– Pour water sample into column– Leave to filter through column– Check ‘clean-ness’ of water

How do I know I am right?

• Fair testing!– Change one thing at a time

(independent variable – filter material)– Measure one thing – ‘clean-ness’ of water

after filtering (dependant variable)– Keep all other things the same – use same

syringe, base water sample, amount of water filtered*, etc (controlled variables)

* Having to ‘measure’ the sample being filtered or amount of filter material can cause some confusion for students – this is preparation measurement NOT the output being measured

Water Filtration

1. Use water from same sample – shake before pouring to ensure well mixed

2. Measure same quantity (10ml)3. Pour water into column4. Repeat 1-3 for other columns (filter materials

are the independent variable)5. Wait for 5 minutes6. Check ‘clean-ness’ of water in beaker

(dependent variable)

Example 3 LEGO car design(ACARA Physical Sciences – Year 7*)

Step 1: the BIG design question

What makes a car go faster?

In this example you are provided with a LEGO car and a variety of wheels...

What research question do you want to answer?

How to run a Fair Test - recap

• Remember– Step 1: What’s the question?– Step 2: State your hypothesis – a guess about how

things will work– Step 3: How do I find the answer?

• Design the experiment

– How do I know I am right?• Change one thing• Measure (or observe) one thing• Keep all other things the same

Resources

• Elsie and the Golden Cows:http://learningplace.com.au/sc/online/Elsie_and_the_golden_cows/pirates_v0_04.html• STAQ website – members only – log-in

requiredwww.staq.qld.edu.au/programs/primary