REQUIRED PRACTICALS PAPER 2

Question 1

investigating reaction time

Answer 1

investigating reaction time

• this requires two people to do the test. Choose who will be person 1 & 2
• person 1 sits on a stool with good upright posture and places the forearm of their dominant arm across the table
• person 2 holds a ruler vertically ; the zero cm mark should be between persons thumb and first finger
• person 2 now drops the ruler at a random time
• Person 1 has to catch the ruler as quickly as possible
• Person 2 now records the measurement on the ruler that is level with the to of persons 1 thumb
• person 1 has a short rest and the test is then repeated several times and a mean is calculated
• convert these results to reaction time using a conversion table
• at the end the two people switch roles to give us another set of results

Question 2

give the independent , dependent and control variable for investigating reaction time

Answer 2

independent variable: person having reaction time measured
dependent variable: reaction time
control variable: starting distance e.g. 0cm , keep conditions in room the same e.g lighting and background noise

Question 3

Investigating Plant Responses
- include independent control and dependent variable

Answer 3

iv: light intensity
dv: height of the seedling
cv: volume of water, type of seed , number of seedlings

• place cotton wool in 3 petri dishes and soak with equal volumes of water
• place 10 mustard seeds in each dish
• leave the dishes in a warm place and allow to germinate
• water the seeds every day with same column of water
• after a few days the seeds with generate
  next use a ruler to measure the height of each seedling
• place the 3 dishes inn different conditions e.g. full sunlight, partial sunlight, and in darkness of a cupboard
• measure the height of each seedling every day for 5 consecutive days
• record the results in a table
• calculate a mean seedling height for each day

Question 4

what are the typical results from the plant response practical

Answer 4

• partial and full sunlight similar as chlorphyll is very efficient at absorbption of light enery
• grow towards light surfacce
• seedlings in dark grow longest as seeds germinate underground growing rapidly to reach light