English chemist John Mayow — refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Phlogiston theory Robert HookeOle BorchMikhail Lomonosovand Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. Becherand modified by the chemist Georg Ernst Stahl by phlogiston theory stated that all combustible materials were made of two parts.
Measuring the rate of photosynthesis Measuring the rate of photosynthesis Without photosynthesis life as we know it would not exist. Plant biomass is the food and fuel for all animals.
Plants are the primary producers. These amazing organisms are capable of capturing the energy of sunlight and fixing it in the form of potential chemical energy in organic compounds.
The organic compounds are constructed from two principle raw materials; carbon dioxide and water which is a source of hydrogen.
These compounds are stable and can be stored until required for life processes. Hence animals, fungi and non-photosynthetic bacteria depend on these for the maintenance of life. But how can we measure the rates at which photosynthesis takes place? The quantities are mind boggling.
There is a total of x tonnes of carbon dioxide in the atmosphere and photosynthesis fixes x tonnes per year. What are the different methods of measuring the rate of photosynthesis? There are a few key methods to calculate the rate of photosynthesis.
Measuring photosynthesis via the uptake of carbon dioxide Using 'immobilised algae' - It's easy and accurate to measure the rate of photosynthesis and respiration using immobilised algae in hydrogen carbonate indicator solution - known as the 'algal balls' technique.
Read the full protocol on using immobilsed algae to measure photosynthesis.
Using a CO2 monitor - More simply, you could put a plant in a plastic bag and monitor the CO2 concentration in the bag using a CO2 monitor. Naturally, the soil and roots must NOT be in the bag as they respire. Alternatively, you could place some Bicarbonate Indicator Solution in the bag with the plant and watch the colour change.
This would best be done with a reference colour chart to try to make the end-point less subjective. This could give a comparison between several plants. There are difficulties with this method, as I'm sure you can appreciate.
The leaf area of the plants should be measured so you can compensate for plant size. Atmospheric air is only ppm CO2, so there is not much CO2 to monitor and the plant will soon run out of CO2 to fix. Measuring photosynthesis via the production of oxygen Oxygen can be measured by counting bubbles evolved from pondweed, or by using the Audus apparatus to measure the amount of gas evolved over a period of time.After learning about Aerobic and Anaerobic Respiration, revise the topic and test yourself to affirm your knowledge.
Extracts from this document Introduction.
Effect of Sodium Hydrogen Carbonate Concentration on the Rate of Photosynthesis Method Firstly I will attach a capillary tube to the nozzle of end of a. Investigating the rate of photosynthesis. This is an example of a common experiment used to investigate light intensity and the rate of photosynthesis.
Suggested Activity 1: Investigating the factors that can affect the rate of photosynthesis.
Investigating the factors that can affect the rate of photosynthesis. Revision summary help for the OCR Gateway Combined Science A 1st biology exam paper - learning objectives. OCR Level 1/2 GCSE (Grade ) in . Play a game of Kahoot! here.
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