Biology Required Practicals Flashcards
Microscopy
Independent Variable: Type of cell
Range: Plant or animal
Dependent Variable: N/A
How it was measured: N/A
Control Variable: Type of microscope
Additional Facts: Aim was to learn how to use a microscope
Osmosis
Independent Variable: Potato slice
Range: different masses
Dependent Variable: % change in mass
How it was measured: Weighed at beginning and end then do change in mass / mass at beginning.
Control Variable: Time in sugar solution, scale, amount dried (to make experiment fair)
Additional Facts: Aim was to investigate osmosis in potatoes.
Food Tests
Independent Variable: What is being tested for
Range: Glucose or protein or lipids
Dependent Variable: If the substance is present or not
How it was measured: Using indicators (Glucose =
Benedict’s solution , Protein = biuret solution, Lipids = N/A, Starch = Iodine).
Control Variable: Mass of food sample, volume of indicator used
Additional Facts: If present, glucose turns orange, protein turns purple, lipids go cloudy (emulsification is formed) and starch goes blue/black.
pH on Enzyme Activity
Independent Variable: pH (buffer)
Range: N/A
Dependent Variable: Presence of starch
How it was measured: Comparison to starch-iodine solution
Control Variable: Volume of starch, volume of amylase, volume of iodine, volume of pH buffer
Additional Facts: Optimum pH is between 6.7 - 7.0
Antiseptics on Bacteria
Independent Variable: Antiseptic
Range: N/A
Dependent Variable: Area of inhibition
How it was measured: measuring and calculating area
Control Variable: Bacteria, volume of antiseptic
Additional Facts:
Photosynthesis
Independent Variable: Distance from light
Range: 10 - 50 cm
Dependent Variable: number of bubbles produced
How it was measured: counted by sight
Control Variable: Light source, pond weed
Additional Facts:
Reaction Time
Independent Variable: Reaction conditions, Person
Range: Visual or auditory
Dependent Variable: Reaction time (where ruler was caught in cm)
How it was measured: Using graphs to convert cm to seconds
Control Variable: Height dropped from
Additional Facts: Each reaction was repeated 3 times to find a mean
Plant Growth
Independent Variable: Light conditions
Range: no light, light from above/side, light all around
Dependent Variable: Growth of seedling and direction
How it was measured: Length measured before and after then range was found
Control Variable: Plant, light source
Additional Facts: Seedling with plant from all around grew the most
Sampling
Independent Variable: Location of sampling, technique used.
Range: Random or systematic sampling
Dependent Variable: number of chosen plant
How it was measured: counted from sight
Control Variable: size of quadrat, chosen plant
Additional Facts:
Effect of temperature on the rate of decay of milk by measuring pH change.
Independent Variable: Temperature
Range:
Dependent Variable: pH change
How it was measured: Universal indicator
Control Variable: Amount and type of milk,
Additional Facts:
