Setting Up Your Photosynthesis Experiment
You'll be investigating how light intensity affects the rate of photosynthesis by counting oxygen bubbles produced by pondweed. The chemical equation for photosynthesis is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
Your independent variable is light intensity (what you change), whilst your dependent variable is the number of oxygen bubbles produced (what you measure). Keep everything else constant - the size of pondweed, volume of water, and temperature.
The key relationship you'll discover is the inverse square law: light intensity = 1/distance². This means if you double the distance from the light, the intensity becomes four times weaker.
Quick Tip: Always use an LED light source rather than a normal bulb - it produces less heat, which could mess up your results by changing the water temperature.
