Photosynthesis "Floating Disk" Lab
The Experiment
Photosynthesis: H2O + Energy + CO2 --> C6H12O6 + O2
The experiment is to test the photosynthesis rate of baby organic spinach. To begin, use the hole puncher to make small circles out of the spinach, make about 5 of these. Second, pull the plunger out of the syringe and place the spinach circles inside. After, re-insert the plunger in the syringe and pull distilled water into the syringe. Tap the syringe to move the air bubbles to the top and push the plunger until all air is gone. Now to remove all air in the spinach circles, place a thumb over the hole and pull down the plunger to cause the inside to become low pressure, hold this for about 20 seconds. Then, with a thumb still over the hole, compress the plunger to create a high pressure area, hold this for an additional 20 seconds. The spinach circles should now begin to sink. Take a beaker and fill it with 100 ml of distilled water and 1g of baking soda. Put the spinach circles into this solution. Now fill a glass dish with distilled water and place it on top of the beaker. This will protect the beaker from heating up and skewing the results. Place a lamp over the dish and beaker and begin timing how long it is before the leaves begin to float again.
Independent variable: This variable can vary because anything changed in the experiment can change the results. Some examples of an independent variable could be color of light used, different solutions amounts of baking soda, or a longer period being held in the low and high pressures in the syringe.
Dependent variable: The dependent variable is the rate of photosynthesis in the spinach circles. This can be recorded by the time it takes for the spinach circles to begin to float again.
Materials
As stated under the independent variables, there are many variables that could be used in this experiment. One of which is the time the spinach circles are held in high and low pressures in the syringe. This would cause even less oxygen to be present in the spinach, which would be replaced with water. This would cause the floating disks to take longer to begin floating because the leaf would have to make even more oxygen than the spinach leaves only held in high and low pressures for 20 seconds.
Questions
a. By creating a vacuum with the syringe oxygen will leave the spinach cells and enter the less concentrated surrounding water. As seen in the "Leaf Cross Section", the leaf's stomas allow for control of oxygen and carbon dioxide to enter and exit the leaf. By causing the surrounding area to have a lower pressure the oxygen and carbon dioxide normally entering and exiting the cell is pulled out.
b. The leaf disks got the carbon dioxide from the baking soda. It accomplished this because the baking soda reacted with the water to release carbon dioxide gas.
c. In the experiment, after being placed in the distilled water with baking soda, the spinach disks began to float. This occurred because of photosynthesis. In photosynthesis, CO2 and other ingredients are needed, the process produces glucose and O2. Though some O2 is released the cells do store some for the aerobic respiration cycle in the plant. The baking soda and water the disks were in react to release CO2 gas which is needed for photosynthesis. Once a light source, or lamp in this case, was available to the disks, they had all they needed to begin photosynthesis again. As the process occurred, the stored oxygen began to displace the water inside the cells and make the density of the disk less then water, thus it begins to float.
The experiment is to test the photosynthesis rate of baby organic spinach. To begin, use the hole puncher to make small circles out of the spinach, make about 5 of these. Second, pull the plunger out of the syringe and place the spinach circles inside. After, re-insert the plunger in the syringe and pull distilled water into the syringe. Tap the syringe to move the air bubbles to the top and push the plunger until all air is gone. Now to remove all air in the spinach circles, place a thumb over the hole and pull down the plunger to cause the inside to become low pressure, hold this for about 20 seconds. Then, with a thumb still over the hole, compress the plunger to create a high pressure area, hold this for an additional 20 seconds. The spinach circles should now begin to sink. Take a beaker and fill it with 100 ml of distilled water and 1g of baking soda. Put the spinach circles into this solution. Now fill a glass dish with distilled water and place it on top of the beaker. This will protect the beaker from heating up and skewing the results. Place a lamp over the dish and beaker and begin timing how long it is before the leaves begin to float again.
Independent variable: This variable can vary because anything changed in the experiment can change the results. Some examples of an independent variable could be color of light used, different solutions amounts of baking soda, or a longer period being held in the low and high pressures in the syringe.
Dependent variable: The dependent variable is the rate of photosynthesis in the spinach circles. This can be recorded by the time it takes for the spinach circles to begin to float again.
Materials
- 100 ml of distilled water
- beaker
- 1 g of baking soda
- hole punch
- syringe
- baby organic spinach
- lamp
- dish
- timer
As stated under the independent variables, there are many variables that could be used in this experiment. One of which is the time the spinach circles are held in high and low pressures in the syringe. This would cause even less oxygen to be present in the spinach, which would be replaced with water. This would cause the floating disks to take longer to begin floating because the leaf would have to make even more oxygen than the spinach leaves only held in high and low pressures for 20 seconds.
Questions
a. By creating a vacuum with the syringe oxygen will leave the spinach cells and enter the less concentrated surrounding water. As seen in the "Leaf Cross Section", the leaf's stomas allow for control of oxygen and carbon dioxide to enter and exit the leaf. By causing the surrounding area to have a lower pressure the oxygen and carbon dioxide normally entering and exiting the cell is pulled out.
b. The leaf disks got the carbon dioxide from the baking soda. It accomplished this because the baking soda reacted with the water to release carbon dioxide gas.
c. In the experiment, after being placed in the distilled water with baking soda, the spinach disks began to float. This occurred because of photosynthesis. In photosynthesis, CO2 and other ingredients are needed, the process produces glucose and O2. Though some O2 is released the cells do store some for the aerobic respiration cycle in the plant. The baking soda and water the disks were in react to release CO2 gas which is needed for photosynthesis. Once a light source, or lamp in this case, was available to the disks, they had all they needed to begin photosynthesis again. As the process occurred, the stored oxygen began to displace the water inside the cells and make the density of the disk less then water, thus it begins to float.
Respiration Lab
Experiment
Respiration: O2 + Glucose --> CO2 + Energy + H2O
The three respirometers are very similar except for the living organism and bead area.
The three different tests have: 1. all beads and no living organisms
2. half the amount of beads and one worm
3. no beads and three worms
For the experiment, it was determined that measuring the volume of the worms would have too high of a risk of killing them so a volume evaluation was not conducted.
The three different tests have: 1. all beads and no living organisms
2. half the amount of beads and one worm
3. no beads and three worms
For the experiment, it was determined that measuring the volume of the worms would have too high of a risk of killing them so a volume evaluation was not conducted.
Conclusion
The respiration rate was clearly visible in the data that reflected on the lab experiment. The sample with 3 worms most clearly demonstrates the respiratiopn rate of the worms. The group increased dramaticdally within the first 10 minutes, then leveled out for the remainder of the tests. The quick rise in respiration levels at the begining may have been caused by the worms trying to burrow into the cotton balls before becoming comfortable and moving less around 10 minutes. The single worm and all beads samples also followed their intended paths at first. The single worms increase originally was attributed to it having had burrowed into the cotton balls before the recording had taken place compared to the 3 worm group. The controll began as intended and remained linear for the initial 10 minutes. For both the single worm and control groups their oxygen levels began to increase unexpectedly at the 10 minute mark. The control may have had an increased oxygen level bcause of an error in measurement or a temperature change. If the interior air was cooler than the water, the copntained air may have had an increased temperature causing it to have a higher pressure and appear to have increased in oxygen levels. On the other hand, the single worm could have had either the same error or phenomenon, but it could have a third explanation. The single worm could have gone through respiration using oxygen and releasing carbon dioxide, but the KOH that was supposed to capture the CO2 could have maxed out its capacity. Thus the carbon dioxide would could the oxygen levels to appear to be increasing instead of decreasing.
There was opportunity for several errors in this experiment, here they are. One is that the 3 samples were plaaced into the water at different times which could mean they were sitting in different temperatures. Second is that the worms begin to try to burrow into the KOH satyurated cotton ball which could have harmed them. Another is that the KOH levels dropped onto each cotton ball coiuld have varied. Fourth, the respirometers could have had leaks that were undetectable skewing the data.
The rate of respiration of the worms in this lab is calculated as follows:
Control: has no respiration rate
1 worm: appears to have had possible error, but initially was
3 worms: on average consumes .0075 mL of oxygen per minute
In the lab, there were three key components needed. One of which was the beads. These were used only to try to keep a similar volume in the three groups, even though they contained different combinations of beads and worms. The KOH was in equal amounts in all three groups respirometers. It's main goal was to capture the CO2 released by the cellular respiration of the worms so only oxygen would be present when being measured. The respirometer played the role of being the reaction chamber. It contained the worms, KOH, and beads while having measurements to be able to determine the amount of oxygen that has been consumed.
There was opportunity for several errors in this experiment, here they are. One is that the 3 samples were plaaced into the water at different times which could mean they were sitting in different temperatures. Second is that the worms begin to try to burrow into the KOH satyurated cotton ball which could have harmed them. Another is that the KOH levels dropped onto each cotton ball coiuld have varied. Fourth, the respirometers could have had leaks that were undetectable skewing the data.
The rate of respiration of the worms in this lab is calculated as follows:
Control: has no respiration rate
1 worm: appears to have had possible error, but initially was
3 worms: on average consumes .0075 mL of oxygen per minute
In the lab, there were three key components needed. One of which was the beads. These were used only to try to keep a similar volume in the three groups, even though they contained different combinations of beads and worms. The KOH was in equal amounts in all three groups respirometers. It's main goal was to capture the CO2 released by the cellular respiration of the worms so only oxygen would be present when being measured. The respirometer played the role of being the reaction chamber. It contained the worms, KOH, and beads while having measurements to be able to determine the amount of oxygen that has been consumed.