Paper 2 required practical Flashcards
(12 cards)
whats the method of the reaction time practical
1.Hold a ruler vertically from one end. The test subject should have their thumb and finger either side of the ruler at the 0cm mark.
2.Drop the ruler. The subject should try to catch it between their thumb and forefinger as fast as possible.
3.Note down the distance from the 0cm mark that the ruler travels before the subject catches it.
4.Use a table to convert this distance into a reaction time.
5.Repeat the experiment on a subject who has just had a coffee.
6.Compare reaction times.
what are the variables for the reaction time practical
The independent variable is whether or not the subject has had caffeine.
The dependent variable is the subject’s reaction time.
whats the method for the plant reposnes practical
1,Line each petri dish with damp cotton wool.
2,Sprinkle 10 seeds evenly on the cotton wool in each dish.
3.Label the dishes A, B, and C.
4.Dish A in full light (control).
5.Dish B in a box with light entering from one side only (unidirectional light).
6.Dish C in complete darkness (optional comparison).
7.Leave for 3–5 days at room temperature, keeping the cotton wool moist.
8.Measure and record the direction and length of growth of seedlings.
what are the variables for the plant responses practical
Independent Variable is the direction of light
Dependant variable is the amount of growth in length and the direction of growth
whats the method for the field investigations practical
1.Use two measuring tapes to mark out a 10m × 10m area
2.Use a random number generator to generate coordinates
3.Place the 1m x 1m quadrat at the randomly chosen coordinate.
4.Record the number of a certain plant species within the quadrat
5.Repeat steps 2–4 at 10 or more random points.
6.Record all results in a table.
7.Calculate mean number of plants per quadrat and multiply it by the area of the field (100m)
what are the variables for the field investigation practical
independant variable is not applicable as its random
dependant varaiable is the amount of flowers in the given area
whats the method for the decay practical
1.Label test tubes for each temperature.
2.Add 5 cm³ of milk and 5 cm³ of sodium carbonate to each test tube. (This makes the solution alkaline.)
3.Add a few drops of pH indicator (e.g. cresol red turns yellow as pH drops).
4.Place each test tube in a water bath at a set temperature. Allow to reach that temperature.
5.Add 1 cm³ of lipase solution to each tube using a pipette then start the stopwatch immediately.
6.Observe and time how long it takes for the indicator to change colour (from purple/red to yellow), showing a fall in pH as fat is broken down and acid is produced.
7.Record the time taken for colour change at each temperature.
8.Repeat experiments twice to get a mean
what are the variables for the decay practical
Independent Variable: Temperature
Dependent Variable: Time taken for the indicator to change colour (rate of decay)
what are some control varaibles for the reaction time practical
Same hand used for the test
Time of day (reaction time can vary throughout the day)
Same person tested (to avoid individual differences)
what are some control variables for the plant responses practical
Number of seeds per petri dish
Amount of water given to each dish
Duration of the experiment (same number of days)
Temperature and humidity of the environment
what are some control varaibles for the field investiagtion practical
Size of quadrat
Time of day when sampling is done (to avoid changes in conditions)
Time of day when sampling is done (to avoid changes in conditions)
what are some control varaibles for the decay practical
Volume of milk used in each test
Concentration and volume of lipase enzyme
Amount of sodium carbonate (to keep pH consistent at start)
Duration before measuring pH change or color change (timing)
