Carolina Maffei, 8SG05/09/2014
PHOTOSYNTHESIS LAB
HOW THE LIGHT AFFECTS THE TIME FOR FIVE DISKS TO RISE UP
AIM:
My aim is to find out how the intensity of the light affects the time for at least fivedisks made out of a leaf to rise up until half a syringe.
TABLE OF VARIABLES:
Variables / Changed? Measured? Controlled?Independent variable / Intensity of the Light / Light intensity is meant as how far is a syringe placed from that source of light.
I’ll put the syringe at different distances from the light. (right next to the source; 10cm from the source)
Dependent variable / Time for five disks to rise up until half my syringe / I’ll measure it with a stop-watch. I’ll start taking the time as soon as I out the syringe next to the light and stop when five disks are half up the syringe.
Controlled variable / 1.The type of the Light
2.The color of the leaf / The same source of light will be used throughout the experiment.
I won’t change the color of the leaf through the experiment.
HYPOTHESIS:
If the intensity of the light is stronger, then the time for the disks to rise up will be less, because the more light we have, the more the Photosynthesis will take place, and the more oxygen will be produced: therefore, faster the disks will start rising.
EQUIPMENT:
-Leaf/Leaves( left in cold water over night);
-Syringe (10cc or greater);
-Water;
-Baking Soda solution (20 g/ 1L of water);
-Beaker;
-Tweezers;
-Paper Punch;
-Syringe Holder;
-Source of Natural or Artificial Light.
METHOD:
-Use the Paper Punch to make 20 disks out of a leaf;
-Put them into your syringe (Push them to the bottom using tweezers);
-Squeeze them to the bottom by adding the plunger of the syringe.
-Suck up 10cc of Baking Soda with water;
-Put your finger on the end of the syringe, and then pull and push continuously the plunger to suck out all the air in the disks, so that they will all be able to sink;
-Once all the disks reached the bottom again, push out the Baking Soda Solution( make only a few ccs remain in the syringe);
-Suck up other 10cc of water(without Baking Soda Solution);
-Put the syringe into a syringe holder, under a source of light;
-Repeat the same process and put the syringe into a further syringe holder in order to run your experiment.
DIAGRAM OF APPARATUS: