Use a light microscope to observe, draw and label biological specimens.

Calculations: Magnification =
size of image ÷ real size of object

Investigate the effect of a range of concentrations of salt or sugar solutions on the mass of plant tissue.

Independent Variable: Concentration of salt/sugar solution
Dependent Variable: Percentage change of mass in plant tissue
Control Variables: Size of potato chips
Volume of salt/sugar solution
Calculations: % change in mass =
change in mass ÷ original mass

Use qualitative reagents to test for a range of carbohydrates, lipids and proteins.

Starch: Iodine (brown to black)
Sugar: Benedict's Solution + Heat (blue to green/yellow/red)
Proteins: Biuret Solution (Blue to purple)
Lipids: Sudan III (Brown to red stained layer)

Investigate the effect of pH on the rate of reaction of amylase enzyme.

Independent Variable: pH
Dependent Variable: Time taken for iodine to remain brown
Control Variables: Volume of amylase solution
Concentration of amylase solution
Temperature

Investigate the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed.

Independent Variable: Distance of pondweed from lamp
Dependent Variable: Volume of oxygen produced
Control Variables: Temperature
Carbon dioxide levels

Plan and carry out an investigation into the effect of a factor on human reaction time.

Independent Variable: Caffeine levels
Dependent Variable: Reaction time
Control Variables: Age of participants
Light levels

Measure the population size of a common species in a habitat. Use sampling techniques to investigate the effect of a factor on the distribution of this species.

Independent Variable: Distance from object
Dependent Variable: Number of particular plants
Control Variables: Time sampled
Sampling method (must be random)
Calculations: Area = length x width

Making soluble salts: preparation of pure, dry copper sulfate crystals.

Chemical Equations:
Copper Oxide + Sulfuric Acid → Copper Sulfate + Water
CuO (s)   +   H2SO4 (aq) → CuSO4 (aq)   + H2O (l)

Investigating what happens when two different aqueous solutions are electrolysed using inert electrodes.

Anode (Positive Electrode): Hydrogen gas will always be observed, unless there is an element less reactive than hydrogen (e.g. copper, silver, gold).

Cathode (Negative Electrode): Oxygen gas will always be observed, unless the solution contains halide ions (fluoride, chloride, bromide, iodide).

Investigate the variables that affect temperature change in chemical reactions, e.g. acid plus alkali.

Independent Variable: Volume of alkali
Dependent Variable: Change in temperature
Control Variables: Room temperature
Volume of acid
Concentration of acid/alkali

Investigate how changing the concentration of a reactant changes the rate of reaction by measuring the decrease in transparency of solution.

Independent Variable: Concentration of sodium thiosulfate
Dependent Variable: Time taken for cross to disappear
Control Variables: Temperature
Volume of sodium thiosulfate
Volume/concentration of
hydrochloric acid

Investigate how changing the concentration of a reactant changes the rate of reaction by measuring the volume of gas produced.

Independent Variable: Mass of marble chips
Dependent Variable: Volume of gas produced
Control Variables: Volume of hydrochloric acid
Calculations: Rate of reaction = change in reactants or products
÷ time taken

Investigate how paper chromatography can be used to separate and identify a mixture of food colourings.

Independent Variable: Ink
Dependent Variable: Distance moved by spot
Control Variables: Solvent used
Calculations: Rf = Distance moved by solute ÷
Distance moved by solvent

Analysing and purifying a sample of water and making it safe to drink.

Independent Variable: Water sample
Dependent Variable: Mass of dissolved  solids
Control Variables: Volume of water

Investigating the specific heat capacity of different materials.

Independent Variable: Material
Dependent Variable: Specific heat capacity
Control Variables: Surface area of material
Calculations: ΔE = m c Δθ

Investigate the effectiveness of different materials as thermal insulators and the factors that may affect the thermal insulation properties of a material.

Independent Variable: Insulation material
Dependent Variable: Water temperature
Control Variables: Starting temperature
Volume of water
Surface area of beaker

What happens to the current through a component when the potential difference across it changes?

Independent Variable: Potential difference
Dependent Variable: Current
Control Variables: Power setting
Temperature

Investigating the density of regularly and irregularly shaped solids and liquids using a range of appropriate apparatus.

Independent Variable: Object
Dependent Variable: Density
Control Variables: Type of fluid displaced
Calculations: ρ = m ÷ v

Investigate the relationship between force and extension of a spring.

Independent Variable: Force
Dependent Variable: Extension
Control Variables: Spring
Calculations: F = k e

How are force, mass and acceleration related?

Independent Variable: Force
Dependent Variable: Acceleration
Control Variables: Mass in system
Surface area of trolley
Gradient
Calculations: F = m a

Observing the properties of waves in liquids and solids.

Independent Variable: Length of wire
Dependent Variable: Resistance
Control Variables: Power setting
Thickness of wire
Temperature of wire
Calculations: v = f λ

Investigating the amount of infrared radiation radiated from different surfaces.

Independent Variable: Surface type
Dependent Variable: Temperature
Control Variables: Starting temperature
Distance of thermometer
Volume of water

Random Error: Chance difference between
observed value and true value.
Systematic Error: Consistent or proportional
difference between observed
value and true value.
Zero Error: Type of systematic error
where base reading is not zero.
Uncertainty: Half the range. Where the
true value can be expected to be.