The Nature of Scientific Investigations (VCE SSCE Chemistry): Revision Notes
The Nature of Scientific Investigations
What is chemistry?
Chemistry is the study of matter—how it behaves and how it interacts with other matter. As scientists, chemists develop their understanding using the scientific method, which involves investigations that are carefully designed, conducted, and reported. Well-designed research builds on existing knowledge and requires careful preparation, accurate measurements, and detailed observations.
The scientific method is a systematic approach that ensures investigations are rigorous, reproducible, and build upon existing scientific knowledge. This structured process helps scientists maintain objectivity and produce reliable results.
Making observations in science
When conducting scientific investigations, you use your senses along with various instruments and laboratory techniques to make observations. These observations fall into two main categories: qualitative and quantitative.
Understanding the difference between qualitative and quantitative observations is fundamental to scientific investigation. Both types of observations are valuable and often complement each other in providing a complete picture of what is being studied.
Qualitative observations
Qualitative observations provide information about what is present in an investigation. These observations describe the qualities or characteristics of what you observe.
Worked Example: Qualitative Observation in Electrolysis
During an electrolysis investigation, you might observe the formation of crystals on the negative electrode. This qualitative observation could indicate that metal ions are being reduced.
What makes this qualitative? It describes what is happening (crystal formation) rather than measuring how much is forming.
Quantitative observations
Quantitative observations provide numerical information that answers questions such as "how many?", "how much?", and "how often?". These measurements must always include appropriate units.
Common Quantitative Observations in Chemistry:
Examples of quantitative observations include:
- Taking a reading on an electronic balance (measured in grams, )
- Measuring initial and final volumes on a burette (measured in millilitres, )
- Recording temperature changes (measured in degrees Celsius, )
Remember: A number without a unit is meaningless in scientific work!
Interpreting observations
How you interpret observations depends on your past experience and existing knowledge. An enquiring scientific mind will use observations to generate further questions.
Worked Example: Generating Questions from Observations
A student observes that when tin(II) chloride solution is electrolysed, metallic crystals form at the negative electrode. Similarly, electrolysing copper(II) chloride produces a red-brown coating on the negative electrode, and lead(II) nitrate also forms metallic crystals.
These observations might prompt questions such as:
- How can we confirm the crystals or coating are made of metal?
- Does electrolysis of all metal compounds produce solid metal?
- Why do some metals form coatings whilst others form crystals at the negative electrode?
- Does the concentration of the aqueous solution affect crystal size?
Many questions cannot be answered through observation alone. They require systematic scientific investigation. Good scientists have sharp powers of observation and curious minds. They rely on evidence and trends, make the most of unexpected discoveries, and carefully record their observations for future reference.
The scientific method
Scientists observe the world around them, consult existing knowledge from other scientists' work, and then ask questions about what they observe.
Scientific inquiry is not a linear process—it's cyclical and iterative. Scientists don't necessarily complete the steps of the scientific method in a fixed order. Some steps may need to be repeated or modified to address the research question more accurately.
A hypothesis is a prediction based on scientific reasoning that can be tested experimentally. This testability is crucial—without it, we cannot apply the scientific method.
Key Stages of the Scientific Method:
The scientific method involves several key stages:
- Formulating a research question
- Developing a hypothesis
- Designing and performing an experiment
- Collecting and analysing results
- Checking whether results support the hypothesis
- Repeating the experiment to verify findings
- Drawing conclusions
If results don't support the hypothesis, scientists modify their experiment or develop a new hypothesis and repeat the process.
Investigation methodologies
Scientists test their ideas using various investigation methodologies. The methodology describes the general approach used to investigate a research question and explains why this approach was chosen.
Methodology vs Method: A Critical Distinction
There is an important distinction between these two terms:
- Methodology: The general approach used to investigate the research question
- Method (or procedure): The specific steps taken to collect data during an investigation
Think of methodology as the "big picture" strategy, whilst the method is the detailed "how-to" guide.
Practical investigations involve direct, hands-on experiences. Suitable methodologies include controlled experiments, simulations, fieldwork, or modelling. In contrast, research investigations might use a literature review or begin with a case study.
| Type of methodology | Explanation |
|---|---|
| Case study | Investigation of a real or hypothetical situation, such as an activity, event, or problem, often involving analysis of data within a real-world context |
| Classification and identification | Using features or properties to classify or identify a substance |
| Controlled experiment | Experimental investigation involving formulating a hypothesis and testing the effect of an independent variable on the dependent variable whilst controlling all other variables |
| Fieldwork | Collecting data outside the laboratory |
| Literature review | Critical analysis of what has already been investigated and published, using secondary data from other people's investigations to explain events or propose new ideas or relationships |
| Modelling | Using models as representations of objects, systems, or processes to aid understanding or make predictions |
| Product, process, or system development | Using scientific understanding and advances in technology to design a new tool, method, or process to meet society's demands or needs |
| Simulation | Using mathematical models or computer simulations to test hypotheses or conduct virtual experiments |
Limitations of the scientific method
The scientific method has important limitations that you need to understand:
Limitation 1: Only Testable Hypotheses Can Be Investigated
The scientific method can only be applied to hypotheses that can be tested experimentally. A hypothesis that cannot be tested can neither be supported nor disproved using the scientific method.
This means questions like "Which painting is more beautiful?" or "Is this action morally right?" cannot be answered using the scientific method.
Limitation 2: Results Are Context-Specific
Even when experimental data supports a hypothesis, this doesn't mean the hypothesis is true in all circumstances. It has only been found to be true under the specific conditions that were tested.
Scientists must be careful not to overgeneralise their findings beyond the conditions of their experiments.
Limitation 3: Ethics and Morality Cannot Be Tested
The scientific method cannot be used to test questions of morality or ethics. These judgements belong to the fields of philosophy, history, politics, and law.
However, science can provide valuable information that people consider when making ethical judgements. For example, science can predict the environmental consequences of pollution or the medical effects of chemical weapons, but it cannot tell us whether these things are morally right or wrong.
Non-scientific factors in investigations
When investigating questions or issues related to chemistry's applications in society, it's important to distinguish between scientific and non-scientific factors. Many investigations into chemical issues must consider non-scientific information, including sociocultural, economic, political, legal, or ethical factors.
The SEPEL Framework
Remember the acronym SEPEL for the five categories of non-scientific factors:
- Sociocultural
- Economic
- Political
- Ethical
- Legal
These factors often overlap and may be classified under more than one category.
For example, discussing climate change involves scientific data (such as atmospheric carbon dioxide concentrations) but must also consider political factors (such as government support for international climate agreements).
Sociocultural factors
Sociocultural factors relate to individuals, communities, cultures, and society. Key questions include:
- Who is directly involved?
- Who will benefit?
- Who might be negatively affected?
Economic factors
Economic factors relate to costs and resources. Key questions include:
- Who will pay for the research?
- Who will fund development, production, and application?
- Will this cause a loss of profit for any stakeholder?
- What costs might the government incur?
Political factors
Political factors relate to government or public affairs. Key questions include:
- What is the relevant government policy?
- Is there disagreement between political parties?
Legal factors
Legal factors connect to laws (legislation) or rules. Key questions include:
- What state legislation covers this area?
- What federal legislation applies?
Ethical factors
Ethical factors relate to moral principles and the need to determine what is right and wrong. Key questions include:
- Does the outcome advantage one group over another?
- Does the outcome prevent anyone from meeting their basic needs?
- Has the investigation been reported honestly, or were unfavourable results omitted?
Worked Example: COVID-19 Vaccine Development
The rapid development of COVID-19 vaccines in 2020-21 demonstrates how a single scientific issue requires consideration of all five categories of non-scientific factors:
| Sociocultural | Economic | Political | Legal | Ethical |
|---|---|---|---|---|
| Why is vaccination necessary? | Who will pay for research, development, and production? | What agreements have been made for the supply of various vaccines? | Have the vaccines been approved for use in Australia by the Therapeutic Goods Administration? | Are there vulnerable groups who should be prioritised for vaccination? |
This example shows that successful scientific applications require balancing multiple competing factors beyond just the scientific data.
Key Points to Remember:
- Chemistry is the study of matter and its interactions, investigated using the scientific method
- Qualitative observations describe what is present, whilst quantitative observations provide numerical measurements with units
- The scientific method is a cyclical process involving research questions, hypotheses, experiments, analysis, and conclusions
- Eight main investigation methodologies exist: case studies, classification, controlled experiments, fieldwork, literature reviews, modelling, product development, and simulations
- The scientific method can only test testable hypotheses and cannot address questions of morality or ethics
- Non-scientific factors (sociocultural, economic, political, legal, and ethical) often influence chemical issues and should be considered in investigations—remember SEPEL!