Reading: Making Trees from Thin Air (Photosynthesis)
Duration: Approximately 45 minutes
Most students have heard of photosynthesis, but what they’ve learned about photosynthesis can now help them to understand chemical reactions. They will now use their new vocabulary to explain in a more precise way something they learned when they were younger.
In chemical equations, the big numbers written before the formula for a chemical show how many molecules of that chemical are used or produced in the reaction compared to the other compounds. The small numbers below and to the right of element symbols are called “subscript” numbers. The subscript numbers refer to the elements in front of them, and show how many atoms of each element go into a compound. For example, an H2O molecule has two hydrogen atoms and one oxygen atom.
No atoms are destroyed or created in a chemical reaction. Atoms are just rearranged. This sameness of mass in reactants and products in chemical reactions is called the Law of Conservation of Matter, because mass is conserved (kept the same) in chemical reactions.
One of the most important chemical reactions for life on earth takes place in plants and is called photosynthesis. Plants take in carbon dioxide (CO2) and water (H2O), and, with a little help from the sunshine, produce oxygen molecules (O2) and sugar molecules. The sugar molecules provide food to animals, but are also used by plants as basic building blocks for their own woody and leafy bodies.
This activity connects the concepts of photosynthesis and conservation of matter.
Students will connect the concepts of photosynthesis and conservation of matter.