rate of photosythesis practical

Question 1

What is the independent variable

Answer 1

The distsnace from light source

Question 2

What is the dependent variable

Answer 2

Number of ubbles produced per min

Question 3

What is the controlled variable

Answer 3

The concentration of sodium hydrogencarbonate using same piece of pond weed each time

Question 4

How to measure dependent variable

Answer 4

Count the number of bubled produced per min

Question 5

Name the 8 stages (method)

Answer 5

1) boiling tube containing 45cm cubed of sodium hydrogen carbonate
2) allow tube stand for min to acclimatise
3) cut pond weed 8 cm long
4) use forcepts to place weed in tube
5) position tube 10cm away from light source
6) coun bubles per min and repeat 5 times
7) calculate average with tube at diff distnaces