NGSS HS-LS2-5 Photosynthesis

One of the really important HS-LS2-5 performance expectations is that students know the inputs and outputs of photosynthesis.  The video below shows a lab I've used for years with my biology students to teach this concept.


The word equation for photosynthesis is summarized below.

carbon dioxide  +  water  +  light  ->  glucose (sugar)  +  oxygen

Students test plants (anarcharis or elodea) in three different types of water.
1. tap water = medium CO2
2. tap water boiled one day before the lab = low CO2
3. tap water with added baking soda = high CO2

The lab also provides an opportunity to introduce (or review) the concept of a limiting reactant since the level of carbon dioxide determines how much oxygen the plants will make as they carry out the light reaction of photosynthesis.


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