Bernarda VasconezCompensation Point: To investigate gaseous exchange in leavesHypothesis:Tube A (covered with aluminum foil and has leaves) will change first and the liquid will turn yellow because it is not photosynthesizing. Tube C (without aluminum foil and leaves) will change second because it photosynthesizing. Tubes D (without aluminum foil and no leaves) and B (covered with aluminum foil, no leaves) will not change. Table 1:TubeAluminumleavesColour at the beggingColour at the end

A Pale pinkYellow

B Pale pinkPale pink

C Pale pinkPale yellow

D Pale pinkYellow

Table 2: (scale from 1-5, 1 being pale pink and 5 being yellow)Time minTest tube

abcd

31111

61112

91112

122223

154234

Strengths: We didnt contaminate the indicator, which made our result more reliable We had an scale for the colour of the indicator from the start of the investigation We discussed in the group which number we should put before having a concluding choiceWeaknesses: We werent constant on the timeSources of error:Source of errorHow to solve it

We didnt use the same clock to measure the time each timeUse a chronometer, or the same clock each time

The light of the lamp was too closePut it in a position where the distance is reasonable

Put the same number of the scale when it had change a littleIf it has changed a little put 0.5 more if you are not sure

The plants may have photosynthesized Put more than two discs of the plant

Ways to improve the experiment: Use a chronometer and try to always take the same time to analyze the test tube Use a more precise scale for the colour of the indicator Put 5 or more disc to make sure that the result wont be so affected if the plants photosynthesize Have enough space to make sure that the light is not so intense or too dim Repeat the experiment if possible 3 or more timesConclusion:In conclusion our hypothesis was not completely correct. Tube A did change the most, but tube D also changed. Which is strange because tube D doesnt have anything, it might have been that oxygen got inside the tube and reacted with the indicator. Throughout the experiment I have learnt that the indicator change of colour with the presence of oxygen in the test tube. Tube A changed the most because it was not photosynthesizing, but it was respiring and by respiring it was giving off oxygen. That means that plants are respiring all the time, during night and day. They only photosynthesize when there is light that means when there is sun.