Every piece of manual apparatus has an inherent margin of error. The systematic uncertainty is typically half of the smallest graduation on the instrument. For example: A thermometer graduated in 1∘C1 raised to the composed with power C steps has an uncertainty of
Connect points with ruled, straight lines (dot-to-dot) unless told otherwise. 5. Identifying Sources of Error
Value of 1 Eyepiece Graticule Unit (EGU)=Number of Stage Micrometer Divisions × Distance per DivisionNumber of Eyepiece Graticule UnitsValue of 1 Eyepiece Graticule Unit (EGU) equals the fraction with numerator Number of Stage Micrometer Divisions cross Distance per Division and denominator Number of Eyepiece Graticule Units end-fraction
: Used to show the detailed features of specific cells, such as xylem vessels or guard cells.
, reject the null hypothesis. The difference between observed and expected results is statistically significant. 6. Exam Strategy & Common Pitfalls Distinguishing Error, Precision, and Accuracy biology 9700 practical notes
For the 9700 Biology syllabus, you will encounter two distinct practical assessments across the AS and A2 levels:
Unlike theory papers, the practical exams don't test rote memorization; they test technique, precision, and error analysis . You cannot "cram" for biology practicals, but you can master a set of core competencies.
Use a ruler to draw straight, horizontal label lines that touch the target tissue or cell precisely. Never cross label lines. Do not use arrowheads. 2. Qualitative Biochemical Testing Protocols
Draw the exact shape of the cells as seen down the microscope—do not draw idealized textbook shapes. Every piece of manual apparatus has an inherent
Dissolve the sample in ethanol, pour into water. A milky white emulsion indicates lipids.
The practical component consists of two parts:
Only draw internal structures if they are visible (e.g., guard cells, chloroplasts, or nuclei). Never draw structures from memory if they cannot be resolved on the slide. 6. Identifying Errors and Suggesting Improvements
Temperature (using a thermostatically controlled water bath), pH (using buffer solutions), and substrate concentration. Understanding Dilution Methods The difference between observed and expected results is
Quantitative experiments require you to gather numerical data to analyze rates of reaction or transport. Investigating Enzyme Concentration and Activity
Simple Serial Dilution: Halving the concentration at each step (e.g., Plant Anatomy Slides Expect to identify and draw tissues from cross-sections of:
You must be able to create a serial dilution. Remember the formula