Looking for a good experiment to increase the amount of inquiry in your lab? Read on…..
The floating leaf disc lab is a standard lab that many Biology teachers use to teach how various variables affect the rate of photosynthesis. It is a pretty easy concept. Cut leaf discs. Flood the mesophyll with sodium bicarbonate solution – the discs sink. As they photosynthesize the O2 will cause the discs to float. The time it takes the discs to float is quantifiable.
Minimally, student groups can select a variable they think might affect the rate of photosynthesis. (Amount of light, temperature of water, type of leaf, etc.) It’s easy and manageable. So, if you haven’t taken the plunge into inquiry yet – this would be a way to dip your toe into the pool. Fairly painless – but very valuable.
It is also the perfect lab to increase the level of inquiry by allowing students to develop the central question. Using their background knowledge of photosynthesis, students can generate a testable question to be answered using the variable of their choosing.
The deep learning happens when students begin to analyze their results. I have them run multiple trials and graph their data prior to analysis so they have a visual to use when trying to decide what is going on. Sometimes they have difficulty deriving meaning from their data, but collaboration and feedback will usually lead to a much deeper understanding of what is happening in the process of photosynthesis.
This is the beauty of inquiry and it is a wonderful thing to watch!