SCIENTIFIC INVESTIGATION Notes, Quizzes & Revision

A scientific investigation is a careful process used to answer questions about the world. It uses observations, tests, measurements and reasoning to produce reliable findings. For learners in Kenya (age age_replace), investigations connect school science to everyday life — for example, testing river water quality, studying plant growth in local soils, or measuring how light affects maize seedlings.

• Observation — noticing and recording facts.
• Question — a clear, testable thing you want to find out.
• Hypothesis — a prediction that can be tested.
• Variable — a factor that can change (independent, dependent, control).
• Method — step-by-step plan for an experiment.
• Data — information collected during an investigation.
• Conclusion — what the data show about the hypothesis.

1. Ask a clear question — e.g., "Does amount of water affect maize seed germination?"
2. Background research — read books, ask teachers, or observe local farms and sources like KEPHIS or agricultural extension officers.
3. Form a hypothesis — a short, testable statement: "If maize seeds receive more water, then they will germinate faster."
4. Identify variables
   Independent (what you change) Dependent (what you measure) Control (what you keep the same)
   Example: independent = water amount; dependent = number of seedlings that germinate after 7 days; controls = seed variety, soil type, sunlight, temperature.
5. Plan the method & materials — write clear steps so others can repeat the experiment. Use locally available materials: seeds, soil, measuring cups, notebooks, thermometers (if available).
6. Collect data — record observations in tables, use drawings or photos, and repeat trials to reduce error.
7. Analyze data — calculate averages, look for trends, draw simple graphs (bar or line charts).
8. Draw a conclusion — say whether the hypothesis is supported and explain using data. Suggest improvements and further questions.
9. Report findings — present results clearly: written report, poster, or short oral presentation to classmates or community (farmers, parents).

• Always wear protective gear (gloves, goggles) when handling chemicals or dirty water.
• Label all samples clearly — do not taste or drink any sample from the field.
• Get permission from teachers or parents before collecting samples from private farms or homes.
• Treat living organisms humanely — return animals or plants to their place when possible or follow teacher guidance.
• Dispose waste safely — follow school rules and local council guidelines for disposal.

• Use local examples to make questions relevant: maize, tea, coffee, river water, soil quality, mosquito breeding sites.
• When equipment is limited, repeat simpler measurements (counts, time to event) and use average results.
• Work in small groups so each pupil practices a different skill: measuring, recording, drawing graphs, or presenting results.
• Link results to community needs — share practical advice from findings with farmers or families (e.g., safe water tips).

Teachers can assess understanding by asking learners to:

• Write a short plan that identifies variables and a clear method.
• Record and present data clearly (table, simple graph).
• Explain whether the data support the hypothesis and suggest an improvement.
• Discuss safety, ethics and real-life applications of the investigation.

• How does amount of water affect the germination of maize seeds?
• Does exposure to sunlight affect growth of school garden vegetables?
• Is river water near the market safe to use? (test for smell, turbidity, simple pH if kits available)
• Which local soil (sandy, loam, clay) holds more water and supports plant growth better?