This simple version of a traditional scientific experiment is a fantastic project to prove that oxygen is a byproduct of photosynthesis. It is best to start it on the morning of a sunny day. The elodea was chosen because it is a plant that gives oxygen in the form of easily observable bubbles.
Steps
Step 1. Prepare the elodea plants
Remove several leaves at the base of the cut stem.
Step 2. Gently place each plant in a jar or beaker
Cut the stem at an angle and gently pound it.
Step 3. Flip a glass funnel over each elodea plant
They should get trapped under the funnel at the base of the jar or beaker.
Step 4. Fill each jar or beaker with water, making it approximately 2.5cm from the top edge
Step 5. Fill two tubes with water
Step 6. Hold a finger or thumb on top of the tube (repeat for each plant)
Gently invert the tube and lower it into the jar or beaker, placing it under water. Remove your finger or thumb and place the tube over the cylindrical part of the glass funnel.
Step 7. Make sure everything is firm and secure
Step 8. Place a jar in the sunlight
On a windowsill it is ideal. Check for bubbles; if you don't see any after 5 minutes, remove the plant, cut a little more of the stem and stomp it again.
Step 9. Place the other jar in a dark area
It will be perfect when closed in a closet. Leave a note on the door that says "Do not open!". This jar will serve as a "control".
Step 10. Leave both jars in their places for one day
Step 11. Run the experiment
At the end of the day, take the jar that has been in the sun and place it in an appropriate place for the experiment. Carefully remove the tube from the jar, keeping it capped with your thumb.
Step 12. Light a match
Quickly extinguish the flame and, while it is still glowing, place the match in the test tube.
Step 13. Repeat this operation with the "control" praise you stored in the dark
Step 14. Observe the results
- You should see that the match placed in the elodea tube exposed to the sun catches fire.
- On the contrary, you should not find any flame coming from the match placed in the elodea tube stored in the dark; rather, since water is still present, the burning of the match should stop.
Step 15. Make a note of your results
You need to understand that the reason the match placed in the tube held in the sun caught fire is that the tube contained oxygen, which is the byproduct of photosynthesis. Photosynthesis is a process by which plants produce their nourishment from carbon dioxide and water. To carry out this process, plants use the energy coming from sunlight thanks to chlorophyll. Plants release the oxygen produced during the photosynthesis process through the stomata. Combustion occurs in the presence of oxygen.
Advice
- It is best to use your thumb, as it is larger and, when you turn the tube upside down, it will prevent water from escaping more effectively than any other finger.
- Thanks to the "check" you can check the results of your experiment to see if they are valid.
- If there is no sun, use a 40-watt lamp directly on the plant to simulate it.
- There are other methods for conducting this experiment, which consist of measuring the rate of photosynthesis by counting the bubbles. See the links below for other versions of this experiment.
