In this lab, students are looking at photosynthesis, which is the process plants use to create their own food.  This is often considered the most important chemical reaction on the planet, because plants are the base of the food chain; even carnivores couldn’t survive without plants because they eat animals that ate plants.  However, photosynthesis is a really complex reaction that takes place in multiple steps, and it is something that you can’t usually see happen.

We wanted to see it happen!  What we did was use syringes to create a vacuum that forced the gases out of spinach leaves.  This made them sink instead of float like they normally do.  We then put them in a solution of baking soda and water and used lamps as a source of light energy, like the sun.  The baking soda provides carbon dioxide.  Plants need light energy, carbon dioxide, and water to make glucose (food).   As plants do photosynthesis, they bring carbon dioxide gas into their cells and they release oxygen gas.  This gas production makes them float again.  So as they move from sinking to floating, you can literally watch them do photosynthesis!