Method
- Set up the apparatus as in the diagram.
- Leave for five minutes for the pondweed to acclimatise to the new light intensity.
- Count the number of bubbles given off in one minute.
- Move the light 10 cm further back.
- Leave for five minutes for the pondweed to acclimatise again.
Why is pondweed used for photosynthesis experiments?
Bright light provides more energy than dim light. Red light is more easily used by the pond weed than most other colours. This process of making sugar and oxygen is called photosynthesis. Pond weed uses the carbon dioxide which is dissolved in the water it is in.
How does light intensity affect photosynthesis in pondweed?
The effect of light intensity on photosynthesis can be investigated in water plants. the light intensity is related to distance – it will decrease as the distance away from the bulb increases – so light intensity for the investigation can be varied by changing the distance from the lamp to the plant.
How are we measuring the rate of photosynthesis in this experiment?
The rate of photosynthesis will be measured by counting the number of oxygen bubbles produced by the Elodea plants in each 2-minute trail. After completing a number of experiments, students and teachers will discuss their findings in relation to macro-level factors that affect ecosystem health and climate change.
Why are plants Destarched before photosynthesis experiments?
It is necessary to destarch a plant before performing photosynthesis experiment because the amount of starch formed during the experiment should be validated. Plants produce starch through an important process called photosynthesis with the help of the chlorophyll pigment that is present in the leaves.
What gas is produced by the pondweed in the light?
The plants will release bubbles of oxygen – a product of photosynthesis – which can be counted. A lamp with an LED bulb is set up at different distances from the plant in a beaker of water: an LED bulb is best as this will not raise the temperature of the water.
What factors affect photosynthesis lab?
1) the variables of light intensity, temperature, carbon dioxide, light quality all influence the rate of photosynthesis.
How is temperature controlled in photosynthesis experiment?
Place the tube in a beaker of fresh water. Place excess sodium bicarbonate (NaHCO3) in the water to give a constant saturated solution of CO2. Place the lamp (the only light source) at a fixed distance from the plant. Maintain the room temperature at 20°C.
Which plant is used for photosynthesis experiment?
Egeria densa, also known as Elodea densa because of its previously incorrect classification in the Elodea genus, is the most popular aquatic plant used to teach photosynthesis in the classroom.
What is photosynthesis equation?
The process of photosynthesis is commonly written as: 6CO2 + 6H2O → C6H12O6 + 6O2. This means that the reactants, six carbon dioxide molecules and six water molecules, are converted by light energy captured by chlorophyll (implied by the arrow) into a sugar molecule and six oxygen molecules, the products.
How do you acclimatise pondweed?
Count the number of bubbles given off in one minute. Move the light 10 cm further back. Leave for five minutes for the pondweed to acclimatise again. Count the number of bubbles given off in one minute. Repeat by moving the lamp away by 10 cm intervals until 50 cm is reached.
What are the independent and controlled variables of pondweed?
1 Independent variable – the light intensity (how close the light is). 2 Dependant variable – the number of oxygen bubbles given off (the rate of photosynthesis). 3 Controlled variables – the size of the pondweed, the volume of water used and its temperature.
Does light intensity affect photosynthesis in pondweed?
Practical – effect of light intensity on photosynthesis in pondweed. The effect of light intensity on photosynthesis can be investigated in water plants. Use Cabomba or Elodea, which are sold in aquarium shops. The plants will release bubbles of oxygen – a product of photosynthesis – which can be counted.
How do you light a pondweed tank?
Set up the apparatus as in the diagram. Leave for five minutes for the pondweed to acclimatise to the new light intensity. Count the number of bubbles given off in one minute. Move the light 10 cm further back. Leave for five minutes for the pondweed to acclimatise again.
