GCSE Biology Required Practical 6 | Investigating the Rate of Photosynthesis (AQA)

Описание: Master the GCSE Biology Required Practical 6 – Investigating the effect of light intensity on the rate of photosynthesis in one clear video. This experiment uses pondweed to measure how changing light intensity affects the rate of photosynthesis.

In this video, we will:

Explain the aim: to investigate how light intensity affects the rate of photosynthesis using an aquatic plant such as Elodea or Cabomba, by measuring oxygen production.

Show the full apparatus setup: beaker, pondweed, water with sodium hydrogencarbonate (for CO₂), lamp, ruler, thermometer and stopwatch.

Walk through the step‑by‑step method, including setting the lamp at a known distance, allowing the plant to acclimatise, and then counting the number of oxygen bubbles per minute (or measuring gas volume) at different distances.

Show you how to change light intensity by moving the lamp and how this links to the inverse square law (light intensity ∝ 1 ÷ distance²).

Demonstrate how to record results in a table, calculate light intensity using 1 ÷ distance², and plot a graph of rate of photosynthesis vs light intensity, identifying the pattern and where another limiting factor takes over.

Identify the independent, dependent and control variables and how to keep the test fair: same plant length, same CO₂ concentration, same time interval, and controlling temperature (heat shield or LED lamp).

Discuss sources of error and improvements, such as counting bubbles consistently, dealing with irregular bubbling, controlling temperature, and repeating for reliability.

✅ Don’t forget to subscribe for more CK's GCSE & A-Level Hubs!

#GCSEBiology #AQA #RequiredPractical #photosynthesis #GCSERevision #BiologyGCSE