The Practical Techniques used to Investigate Photosynthesis

Use of the Pondweed Experiment: Through this technique, you can investigate the rate of photosynthesis under different light intensities. Submerge a piece of pondweed in water, place a lamp at varying distances and count the number of bubbles produced over a set period.
Elodea Canadensis (Canadian waterweed): This is a popular plant used in school labs to study photosynthesis. The reason being it’s an aquatic plant and gives off bubbles of gas (oxygen) from a cut stem when photosynthesising, making it easy to assess the rate.
Use of a Colorimeter: This device measures how much light is absorbed by a solution. The stronger the colour, the more light it absorbs. In photosynthesis studies, it’s used to measure the percentage of light absorption by chlorophyll extract.
Use of Data Loggers: Data loggers can automatically collect data over a period of time, tracking changes in light intensity, temperature, etc. This is particularly useful when studying the effects of different environmental conditions on photosynthesis.
Hydrogen Carbonate Indicator: This is a solution that changes colour depending on the concentration of carbon dioxide, hence can be used to measure the rate of photosynthesis (CO2 intake).
Use of a Quadrat: Used in fieldwork, it’s a simple square frame (generally 1m x 1m) used to define the sample area. It’s used to study the distribution or the abundance of plants species in a given area, indirectly providing insights about photosynthesis.
Starch Test: After photosynthesis, plants store glucose as starch. Smearing iodine solution on a leaf from a plant which has been photosynthesising will turn the leaf blue-black if starch is present, giving an indication of photosynthetic activity.
Designing a fair test is vital for any investigation. To ensure the outcomes are due to the variable being investigated, for example, light intensity, ensure all other factors such as carbon dioxide concentration and temperature are kept constant.
Accurate measurements: Precision is very important in experiments. Always ensure accurate measurement of variables like light intensity, time or carbon dioxide concentration.

Remember, safety is always of paramount importance in any scientific investigation. Handling lamps and glassware require extreme care. Wear goggles and aprons when dealing with chemicals.