IAP Class # 6

Class 6: More Molecules, for Life

Review atoms and molecules (NaCl, H₂) from last time, and idea of their motion, heat. Introduce more examples of energy: motion, heat, Sunlight, chemical; needed for life processes.

After reintroducing H and O, introduce a new atom: C, and talk about it. "Coal", fires, and burning: what's needed?

Fuel (name some types - anything that burns, including sugar; coal easiest to describe)
Air - specifically, OXYGEN
Heat is also involved - possibly some to start, a lot coming out

Demo of oxygen's diatomic molecule, and "coal" - one carbon atom (large black styrofoam sphere), and "burn" the coal, producing CO₂. Then show typical "hydrocarbon" CH₄, explain name, relate to oil, etc., and demo "burning" that (producing CO₂ and H₂O). Finally, describe "carbohydrate" - explain name, get them to give examples. "Food is fuel!"

Materials for Hands-on Activities (per group of 3-5 students)

1 C atom (large black styrofoam ball)
2 H atoms (small blue styrofoam balls)
3 O atoms (large white styrofoam balls)
4 toothpicks (for attaching atoms to each other)
3 colored paper cards: yellow, green, pink

Hands-on Activity - Modelling Photosynthesis and Respiration

Food is our fuel - it gives us energy when we burn it in our bodies, using oxygen we breathe. How does the energy get into the sugar? How is the sugar made? Where does the energy come from? (Get students' answers)

Each group at each table manipulates the atoms to show the processes of PHOTOSYNTHESIS (explain name) and RESPIRATION:

Assign roles within each group (by colored card choice): a "Sunlight" student, a "Plant" student, and an "Animal" student
If more than 3 students, have the 1 or 2 extras assemble H₂O and CO₂ from individual atoms
"Sunlight" student breaks apart the CO₂ and H₂O into atoms
"Plant" student then assembles the atoms into simple sugar - HCOH - and "leftovers" (discuss what is left over, make diatomic)
"Animal" student then takes molecules produced, representing "eating" the sugar and breathing the oxygen, and reassembles atoms into products of resspiration: CO₂ and H₂O

Take some time to draw and write up a description of what we just did, including how it's important to us and to ALL LIFE! Note that this endless back-and-forth is happening around us all the time. Earth is an ECOSYSTEM, powered by the Sun!