BIOLOGY PAPER 2:
REACTION TIME REQUIRED PRACTICAL 7:
1. SIT on a chair and place your forearm of your WEAKER HAND on the table with you hand
hanging over the end of the table
2. Someone else should hold a METRE RULER in line so that the 0cm mark is level with the top
of your thumb.
3. Your partner should DROP the ruler without telling you
4. CATCH the ruler as QUICKLY as you can
5. NOTE and RECORD the number level with the TOP OF YOUR THUMB after you have caught
the ruler.
6. Repeat this at least 5 times
7. Swap places and repeat the steps for the other person
INDEPENDENT VARIABLE- the person catching the ruler
DEPENDENT VARIABLE – the effect of repetition on the reaction time
CONTROL VARIABLES- same ruler, held from same height.
ERROR SOURCES –
Participants may have performed similar tasks so are quicker to react.
Sample size may be too small to make a valid conclusion.
PLANT RESPONSES REQUIRED PRACTICAL 8:
1. Pour a fixed volume of water into 3 petri dishes and add cotton wool.
2. Place 10 seeds in each petri dish
3. Place the petri dishes in a WARM location
4. Allow time for the seeds to germinate
5. Place one petri dish in FULL SUNLIGHT , a second petri dish in PARTIAL SUNLIGHT and a third
petri dish in DARKNESS.
6. Use a RULER to measure the height of each seedling everyday for at least a week
7. Record in a table
8. Find the mean height
9. Plot the graph of mean height of each seedling
INDEPENDENT VARIABLE- location of the plants
DEPENDENT VARIABLE- mean height of seedlings
CONTROL VARIABLE-
Number of seeds on each dish
Volume of water the seedlings that are given
Temperature they are kept at
ERROR SOURCES-
Seedlings in the same petri dish may not receive the same exposure to sunlight.
Sample size for each environmental condition may be too small.
Temperature is not controlled but can affect results
REACTION TIME REQUIRED PRACTICAL 7:
1. SIT on a chair and place your forearm of your WEAKER HAND on the table with you hand
hanging over the end of the table
2. Someone else should hold a METRE RULER in line so that the 0cm mark is level with the top
of your thumb.
3. Your partner should DROP the ruler without telling you
4. CATCH the ruler as QUICKLY as you can
5. NOTE and RECORD the number level with the TOP OF YOUR THUMB after you have caught
the ruler.
6. Repeat this at least 5 times
7. Swap places and repeat the steps for the other person
INDEPENDENT VARIABLE- the person catching the ruler
DEPENDENT VARIABLE – the effect of repetition on the reaction time
CONTROL VARIABLES- same ruler, held from same height.
ERROR SOURCES –
Participants may have performed similar tasks so are quicker to react.
Sample size may be too small to make a valid conclusion.
PLANT RESPONSES REQUIRED PRACTICAL 8:
1. Pour a fixed volume of water into 3 petri dishes and add cotton wool.
2. Place 10 seeds in each petri dish
3. Place the petri dishes in a WARM location
4. Allow time for the seeds to germinate
5. Place one petri dish in FULL SUNLIGHT , a second petri dish in PARTIAL SUNLIGHT and a third
petri dish in DARKNESS.
6. Use a RULER to measure the height of each seedling everyday for at least a week
7. Record in a table
8. Find the mean height
9. Plot the graph of mean height of each seedling
INDEPENDENT VARIABLE- location of the plants
DEPENDENT VARIABLE- mean height of seedlings
CONTROL VARIABLE-
Number of seeds on each dish
Volume of water the seedlings that are given
Temperature they are kept at
ERROR SOURCES-
Seedlings in the same petri dish may not receive the same exposure to sunlight.
Sample size for each environmental condition may be too small.
Temperature is not controlled but can affect results
