RESOURCES FOR QUEENSLAND STUDENTS & TEACHERS

'DEADLY' EXTENDED RESPONSE TASKS

Ideas for writing ERTs for Year 11 and 12 Chemistry

From Dr Richard Walding, FAIP, FRACI, CChem, Griffith University, Australia
Author New Century Senior Physics textbook by Oxford University Press.  
Email: r.walding@griffith.edu.au


An Extended Response Task (ERT) is an assessment instrument that requires you to respond to a "science question, statement, circumstance or issue". It is essentially non-experimental, but will require research and use of secondary (someone else's) data – although you may have to draw on primary (your own) experimental data. This webpage concerns completing an Extended Response Task in Queensland (Australia) Senior Chemistry in the persuasive exposition genre. It refers to criteria and task types from the syllabuses produced by the Queensland Studies Authority but is not meant to imply that the QSA endorses any of the comments. It is a personal opinion.


TECHNIQUES FOR PREPARING A ERT IN CHEMISTRY


In an ERT students are required to respond to a science question (a Research Question), statement (Thesis), circumstance or issue (Stimulus) related to their curriculum. It is essentially non-experimental, but requires research and use of secondary data – although students may have to draw on primary experimental data. An ERT can be created  by stating a Topic/Focus (F), providing a Stimulus or Scenario, and generating a Research Question and a Thesis, viz:

Topic: Thermochemistry and Fuels (Teacher given = closed; student generated = open).

 

Stimulus: At some time in the future, we will not be able to satisfy our expectations of a high standard of living if our transport system continues to rely on fossils fuels as our primary source of fuel. Alternatives to the petrol, diesel that drive our land-based infra-structure are in development, and it is imperative that research and development of these fuels continues so that we can switch from using fossil fuels to renewable fuels without a drop in our standard of living. Into which one/s should we be investing our intellect, time, money and efforts?  One politician said "When it comes to comparing two fuels, say Fuel X and Fuel Y, the single most important factor in determining which has the greater potential as a transport fuel would have to be the heat of combustion of the fuel itself." A colleague said, "I agree. The energy output must underpin all of our discussions about our future energy choices. And when we talk about one fuel having a greater potential as a fuel over another type, having the greatest molar heat of combustion means that it better satisfies these criteria of a good fuel." (Stimulus given by teacher).



Research Question: Do you agree with the statement that the molar heat of combustion is the most important consideration for a good fuel? (Teacher given = closed; student generated = open).



Thesis: Molar heat of combustion alone is not the best criteria for judging a good fuel.   (Teacher given = closed; student generated = open)

 

Topic: Organic Chemistry - Drugs, Medicine & Society (Teacher given = closed; student generated = open).



Stimulus: The study of Drugs, Medicine and Society is vast and encompasses many issues related to chemistry, such as the chemical and physical properties of the drugs, the history of their development, their uptake by the body, their mode of action, metabolism, and so on. In class, you have studied some of these aspects in relation to acetylsalicylic acid (Aspirin). However, while we can appreciate that a good therapeutic drug is one which, loosely defined, promotes healing, what other features would be desirable of a 'good drug'? (Stimulus given by teacher).

Research Question: Which is better, aspirin or paracetamol? (Teacher given = closed; student generated = open).

Thesis: Based on only its chemical/biochemical properties, aspirin is a better drug than paracetamol.   (Teacher given = closed; student generated = open)

 

Topic: Redox Reactions & Acid-base Equilibrium: Swimming Pool Chemistry (Teacher given = closed; student generated = open).





Stimulus: It is the dream of many people to have a swimming pool in their backyard. An important aspect of maintaining a pool is to understand the chemistry of the pool water itself. Knowing how factors such as pH, total alkalinity and chlorine level affect pool water balance is an essential part of caring for and maintaining a pool. The most common method of sanitising backyard swimming pools at present is the saltwater electrolysis method which results in the formation of the hypochlorite ion, OCl-. Some companies have developed alternatives to 'chlorine' as the sanitiser in pools. Pool owners ask "what are two of these alternatives"?  Knowledge of the chemistry involved in them and their effectiveness would help a pool owner compare these to ‘chlorine’ as a pool water sanitiser. (Stimulus given by teacher).

Research Question: Which is better, salt water chlorination or liquid hypochlorite? (Teacher given = closed; student generated = open).

Thesis: Chlorine sanitiser is the best method to sanitize a backyard swimming pool.    (Teacher given = closed; student generated = open)

EXAMPLES

The list below show examples of Focus Areas (F),  Research Questions (RQ) and Thesis statements (T) for use in a Persuasive Exposition ERT in Physics.  Note: these will not necessarily apply to other genres used for ERTs in Physics.

Examples of Topic/Focus areas:

Examples of Research Questions

Examples of Thesis Statements


CHANGING THE DEGREE OF OPENNESS OF INQUIRY (NON-EXPERIMENTAL)


The degree of openness of an ERT inquiry can be varied by changing the parameters of the task. The following table shows how this can be achieved. It does not necessarily mean that the complexity or challenge of the task increases with increasing open-ness, just the control the student has over the process. Level "0" Openness (verification) can apply equally to inquiry tasks or "closed" non-inquiry problems where the data is given and there is a "correct" answer; eg: calculate the pH of a solution of 0.15 M HCl. In Senior Chemistry students are most likely to be dealing with Level 2a Openness and above in their ERTs.
 

Change in Openness
Openness Level
Focus
Research Question
Thesis
Outcome
Common Name
Closed
0
Given
Given
Given
Closed
Verification
-
1
Given
Given
Given
Open
Guided Inquiry
2a
Given
Given
Open
Open
Open Guided Inquiry
-
2b
Given
Open
Open
Open
Open Guided Inquiry
Open
3
Open
Open
Open
Open
Open Inquiry

 

Sample ERT task - Greenhouse gases, Ozone and Pollution


This is a sample of an ERT to show how it can be set out. It can be downloaded here: Sample ERT.