Scientific Inquiry and Skills
Core concepts
Scientific inquiry follows a process: observe, ask a question, form a hypothesis, design a controlled experiment, collect and analyze data, and draw conclusions. A hypothesis is a testable prediction. The independent variable is changed by the researcher; the dependent variable is measured; controlled variables are kept constant. A control group provides a baseline for comparison. Data can be qualitative (descriptive) or quantitative (numerical). Graphs should match the data type: line graphs for continuous change, bar graphs for categories. Accuracy refers to closeness to the true value; precision refers to consistency among measurements. Sample size and repetition improve reliability. Conclusions should be based on evidence, and results should be communicated clearly.
Common traps
Questions often confuse independent and dependent variables, or identify the control group incorrectly. Do not assume correlation proves causation. Distinguish accuracy from precision. Remember that a hypothesis can be supported or rejected but not proven absolutely. Watch for bias and missing controls.
Worked example
A student tests whether fertilizer affects plant height. Fertilizer amount is the independent variable; plant height is the dependent variable; soil, light, and water are controlled. A group with no fertilizer is the control. Rule of thumb: change one variable, measure one variable, and keep everything else the same.