What is a scientific investigation?
A scientific investigation is an organised way of finding answers to questions about the world. Instead of guessing, scientists follow a series of steps so their results are fair and can be trusted. This process is sometimes called the scientific method.
The main steps
A typical investigation follows these steps in order:
- Identify the problem: ask a clear question to investigate.
- Make a hypothesis: a smart, testable guess about the answer.
- Plan the experiment: decide what to do and what to measure.
- Collect data: carry out the experiment and record the results.
- Analyse the data: study the results, often using tables and graphs.
- Make a conclusion: decide whether the hypothesis is supported.
Key idea
A hypothesis is a testable prediction. A conclusion states what the results show and whether they support the hypothesis.
Variables in an experiment
To keep a test fair, we control the variables. The manipulated variable is the one we change. The responding variable is the one we measure. The fixed variables are kept the same so the test is fair.
Example
To test how sunlight affects plant growth, sunlight is changed (manipulated), plant height is measured (responding), while water and soil are kept the same (fixed).
Remember
- Investigations follow ordered steps, starting with a question.
- A hypothesis is a testable guess.
- Keep fixed variables the same to make a fair test.