Quick tips for acing paper 6
When planning your experiment, make sure you cover the CORMSS
Requirement Explanation
C: Change Independent variable: What you change in the experiment (what you’re
studying the effect of)
Depending on your objective, identify the independent variable (factor
you’re investigating) and design how you’ll change it. You can either
1. place a range of values: always have a minimum of 5 values in range
(e.g. if you’re investigating the effect of pH on enzyme activity,
measure the activity at a pH of 2, 4, 6, 8, 10
2. Have two groups, one with the factor (e.g plant exposed to sunlight)
and one without (e.g. plant in the darkness)
State a clear method of how you’re going to set the indpendent
variable, e.g. use water baths to set different temperatures, use buffer
to set different pHs..)
O: Organism What species/size/age/gender will you use?
If you’re planning an investigation into enzyme activity, identify the
enzyme and the substrate
You can use the organism to set control variables, e.g. use same type of
plant (e.g. all apple pieces from the same plant, all potato pieces from
the same plant, all plant samples of the same species, same age..)
R: Repeat Take more than one reading- you should take a minimum of 3 readings
and repeat the whole experiment
M: Measure What will you be measuring, i.e. dependent variable (e.g. colour change,
number of bubbles..)
how often (e.g. every 2 minutes)
what are the units (number, cm, cm3)
describe, in a clear deptailed manner how you will take the
measurement, and with what equipment.
S: Same State the factors you will keep the same (control variables) to make sure
you have carried out a fair valid test, e.g. temperature/light
intensity/volume of water etc.
S: Safety Safety precautions related to your experiment
Control Many experiments need two groups, namely an experimental group and
a control group. This is because if you only have a group where you
change your IV (an experimental group), you cannot tell what would
have happened if you did not change your IV.
Therefore a control group involves replicating everything about the
experimental group, except for keeping the IV the same. This allows you
to test if the IV is having a true effect on the DV
When an experiment involves a range of independent variable values
A control is when you place everything but what you are testing, e.g. a
test tube that has water, the substrate but not the enzyme
4
, Magnficiation
magnification = image size ÷ actual size
Make sure the image size and actual size are both in
the same units (e.g. both are in millimetres (mm) or
both are in micrometres (μm)
When using a ruler, careful: change cm to mm (cm
to mm: multiply by 10).
Calculate magnification and size of biological specimens using millimetres as units
Convert measurements between millimetres (mm) and micrometres (μm) where
necessary ( 1mm = 1000 μm), (1 μm = 0.001 mm)
Mm to m: multiply by 1000, mm to m: divide by 1000
Recording your data
Your table should have the independent variable as the firt column.
Make sure to include clear headings with units
Don’t put units with data in the body of a table (only at the heading)
Data should be recorded to the appropriate number of significant figures
Biological Drawings- doS and don’ts
• DO Draw using a sharp pencil
• DO Draw clear, unbroken lines
• DON’t shade or colour unless stated otherwise
• DO Draw to scale unless stated otherwise
• DO Draw larger than the specimen unless stated otherwise. Take about three
quarters of the space provided for drawing!
DO clearly label major structures or features using a ruler
When Drawing: LLLDPN
• L: Lines: Clear, single, unbroken (NO Sketching)
• L: Large: Your drawing must take at least two thirds of the space provided
• L: Label your drawing
• D: Detailed
• P: Proportional
N: NO shading
When Graphing: just SLAAP
• S stands for Scale: choose a linear scale on the two axes that uses up at least 2
thirds of the space provided
• L stands for Line: join each point to the next with a straight line. This “dot to dot”
plotting shows the trend in results. But read the question carefully – the examiner
MAY WANT YOUu to plot a “line of best fit” or a freehand curve through the
points. If they don’t explicitly mention it, get a ruler and join dot to dot with
straight lines.
• A stands for Axes: The thing that you have altered in your experiment (the
independent variable) always goes on the X axis. The thing that you
have measured in your experiment (the dependent variable) always goes on the Y
axis.
• A stands for Axes (again): this mark is for labelling your axes correctly, with
numbers AND units
• P stands for Points: correct plotting
5
When planning your experiment, make sure you cover the CORMSS
Requirement Explanation
C: Change Independent variable: What you change in the experiment (what you’re
studying the effect of)
Depending on your objective, identify the independent variable (factor
you’re investigating) and design how you’ll change it. You can either
1. place a range of values: always have a minimum of 5 values in range
(e.g. if you’re investigating the effect of pH on enzyme activity,
measure the activity at a pH of 2, 4, 6, 8, 10
2. Have two groups, one with the factor (e.g plant exposed to sunlight)
and one without (e.g. plant in the darkness)
State a clear method of how you’re going to set the indpendent
variable, e.g. use water baths to set different temperatures, use buffer
to set different pHs..)
O: Organism What species/size/age/gender will you use?
If you’re planning an investigation into enzyme activity, identify the
enzyme and the substrate
You can use the organism to set control variables, e.g. use same type of
plant (e.g. all apple pieces from the same plant, all potato pieces from
the same plant, all plant samples of the same species, same age..)
R: Repeat Take more than one reading- you should take a minimum of 3 readings
and repeat the whole experiment
M: Measure What will you be measuring, i.e. dependent variable (e.g. colour change,
number of bubbles..)
how often (e.g. every 2 minutes)
what are the units (number, cm, cm3)
describe, in a clear deptailed manner how you will take the
measurement, and with what equipment.
S: Same State the factors you will keep the same (control variables) to make sure
you have carried out a fair valid test, e.g. temperature/light
intensity/volume of water etc.
S: Safety Safety precautions related to your experiment
Control Many experiments need two groups, namely an experimental group and
a control group. This is because if you only have a group where you
change your IV (an experimental group), you cannot tell what would
have happened if you did not change your IV.
Therefore a control group involves replicating everything about the
experimental group, except for keeping the IV the same. This allows you
to test if the IV is having a true effect on the DV
When an experiment involves a range of independent variable values
A control is when you place everything but what you are testing, e.g. a
test tube that has water, the substrate but not the enzyme
4
, Magnficiation
magnification = image size ÷ actual size
Make sure the image size and actual size are both in
the same units (e.g. both are in millimetres (mm) or
both are in micrometres (μm)
When using a ruler, careful: change cm to mm (cm
to mm: multiply by 10).
Calculate magnification and size of biological specimens using millimetres as units
Convert measurements between millimetres (mm) and micrometres (μm) where
necessary ( 1mm = 1000 μm), (1 μm = 0.001 mm)
Mm to m: multiply by 1000, mm to m: divide by 1000
Recording your data
Your table should have the independent variable as the firt column.
Make sure to include clear headings with units
Don’t put units with data in the body of a table (only at the heading)
Data should be recorded to the appropriate number of significant figures
Biological Drawings- doS and don’ts
• DO Draw using a sharp pencil
• DO Draw clear, unbroken lines
• DON’t shade or colour unless stated otherwise
• DO Draw to scale unless stated otherwise
• DO Draw larger than the specimen unless stated otherwise. Take about three
quarters of the space provided for drawing!
DO clearly label major structures or features using a ruler
When Drawing: LLLDPN
• L: Lines: Clear, single, unbroken (NO Sketching)
• L: Large: Your drawing must take at least two thirds of the space provided
• L: Label your drawing
• D: Detailed
• P: Proportional
N: NO shading
When Graphing: just SLAAP
• S stands for Scale: choose a linear scale on the two axes that uses up at least 2
thirds of the space provided
• L stands for Line: join each point to the next with a straight line. This “dot to dot”
plotting shows the trend in results. But read the question carefully – the examiner
MAY WANT YOUu to plot a “line of best fit” or a freehand curve through the
points. If they don’t explicitly mention it, get a ruler and join dot to dot with
straight lines.
• A stands for Axes: The thing that you have altered in your experiment (the
independent variable) always goes on the X axis. The thing that you
have measured in your experiment (the dependent variable) always goes on the Y
axis.
• A stands for Axes (again): this mark is for labelling your axes correctly, with
numbers AND units
• P stands for Points: correct plotting
5
