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Biology Practicals - A you n d to know
1. Practical Skills Overview
Planning: Understand what a fair test is (control variables, independent/dependent variables). Observation & Measurement: Accuracy with instruments (ruler, thermometer, stop clock, microscope). Recording Data: Tables with clear headings and correct units. Analysis: Graph plotting (independent variable on x-axis), identifying trends. Evaluation: Comment on accuracy, reliability, improvements to method.
2. Common Apparatus and How to Use Them
Apparatus Usage Beaker Hold/mix solutions Test tube Hold small reactions Measuring cylinder Measure liquid volumes accurately Thermometer Measure temperature Stopwatch Measure time intervals Microscope Observe slides; know parts and functions Dropper/Pipette Add small, controlled volumes Ruler Measure length (e.g., seedlings)
3. Core Biological Techniques
1. Food Tests (Know color changes and reagents)
Test for Reagent Positive Result Starch Iodine solution Blue-black Glucose Benedict's + heat Brick-red (orange/yellow if less) Protein Biuret solution Purple/lilac Lipid Ethanol + water Cloudy/milky white
2. Microscope Use
Start on low power objective. Use coarse focus first, then fine focus. Know how to calculate magnification : Total Magnification = Eyepiece × Objective lens Measure specimens using an eyepiece graticule (if included).
3. Osmosis Experiments
Using potato cylinders or dialysis tubing. Measure change in mass or length after soaking in solutions. Know how to interpret % change and graph results.
4. Enzyme Activity
E.g., amylase breaking down starch. Factors: temperature, pH. Test at intervals using iodine in spotting tiles. Graph rate of reaction or time taken for starch to disappear.
- Recording Results Use tables with headings and units. Label everything clearly. Units in column headings only (not in cells). Example:
Word What to do Describe Say what you see Explain Give reasons using biology knowledge Compare Identify similarities AND differences Evaluate Discuss strengths, weaknesses, improvements Suggest Apply logic and biological understanding
- Safety in the Lab Wear goggles when heating or using chemicals. Tie hair back , no loose clothing. Handle glassware and hot objects with care. Dispose of biological waste properly.
