Rates Of Photosynthesis Flashcards
What substances do green plants use in the presence of light energy to produce glucose and oxygen?
Carbon dioxide and water
What factor is being changed to affect the rate of photosynthesis (dependent variable)?
Light intensity
What type of plant is use in the practical?
Pond weed
What solution is added to the boiling tube to encourage photosynthesis?
Sodium hydrogen carbonate solution
Why is the stem of the pond weed cut underwater?
To make it easier to see oxygen being produced
What is measured to determine the rate of photosynthesis (independent variable)?
Number of oxygen bubbles
Why should the number of oxygen bubbles be counted from the cut stem?
To keep it a fair test
Is the pond weed cut at an angle? Why?
Yes - ensures a steady stream of oxygen bubbles
How is light intensity changes in the experiment
Distance to the light source
Why is LED light source better than a regular light bulb?
Gives off less heat
Why should the overhead lights be turned off during the experiment?
Control the light source
How many values of the independent variable should be tested?
Five
What is an error that could be introduced in the first method?
Bubbles may not be the same volume
Alternative method for measuring the rate of photosynthesis?
Collecting volume of oxygen
What is used to trap the pond weed?
Glass funnel
What is placed over the funnel to collect the oxygen?
Boiling tube full of water
What happens to the water in the boiling tube as oxygen is collected?
It is displaced
