Photosynthesis
People cannot make food.
People grow food.
Plants make food.
This is why agriculture is so important.
Sunlight Energy
6 CO2 + 6 H2O → → → → → C6H12O6 + 6O2
Chlorophyll
Chloroplasts
C6H12O6
Sugar - Glucose
LEQ:
1.
2.
3.
4.
5.
How does photosynthesis impact living organisms?
What are the byproducts of photosynthesis?
How does cellular respiration provide energy for organisms?
What is the main product of photosynthesis?
What do people get from consuming the main product of photosynthesis?
Day 1: Taste the main product of photosynthesis. Other tastes of photosynthesis, corn syrup, coconut sugar,
sugar cane sugar, beet sugar, molasses, honey, maple syrup, maple sugar, (white sugar, raw sugar, brown
sugar).
Day2: Cover the chemical formula for photosynthesis. Have them write it down, verbally say it repeatedly and
go over it with their shoulder partner.
Day 3: Reverse Engineer Photosynthesis i
Show students that the ingredients in glucose; Carbon, Hydrogen, and Oxygen can be removed
A marshmallow is basically sugar - glucose
Burn a marshmallow – the black is Carbon. The carbon originally came from CO2 and is stored as the C in
C6H12O6. The fire is aided by the Oxygen the air.
The fire is releasing the sunlight energy put into the sugar by photosynthesis. Sunlight energy was converted to
chemical energy and then to hear and light energy.
Burn marshmallow inside of a glass jar. The condensation (water) that accumulates on the inside of the jar was
stored in the glucose as H12O6.
The main ingredient in marshmallows is sugar (glucose, a carbohydrate). Glucose is the carbohydrate made in
the Photosynthetic process. So where does sugar come from? Plants. During photosynthesis, the plant used only
3 things to make sugar: water taken up by its roots, CO2 (Carbon Dioxide) taken in through the stomata, and
energy from the sun.
Plants take in Carbon Dioxide (CO2) made of Carbon and Oxygen and they give back to us Oxygen which we
breathe. Plants keep the Carbon. Then we breathe in the oxygen and give Carbon Dioxide (CO2) back to them.
What is Carbon? Carbon is the black stuff that is left behind when you burn something. Burn a rolled up piece
of paper with a blow torch. Anything that turns black when you burn it contains the element Carbon. The paper
contains carbon put there by the growing plant.
So plants take in CO2, water, and sunlight and change those three things into sugars. Let’s toast a marshmallow
and take that sugar apart. Toast the Marshmallow black with a hand held blow torch. Let it burn. You can see
that we are getting energy out of that marshmallow. The plan puts energy in, in the form of sunlight and we get
energy out in the form of light and heat in the form of flame. And what is this black stuff on the outside of the
marshmallow? It is Carbon. We are also getting back the water even though we can’t see it. The water is going
into the air in the form of water vapor. You can’t see water vapor. Have some charcoal to show them the black
of burned carbon.
However, if I set the Marshmallow on fire again and place it inside of this glass jar, you can see the water vapor
released in the form of condensation on the inside of the jar. Have a student put their hand in to feel the
moisture. Everything that the plant put into the sugar we got back – the Water, the Carbon , and the Energy. I do
this over and over, telling them that I would love for them to eat a marshmallow but the district won’t allow me
to give them something to eat that is not individually wrapped.
There is another way you can take a Marshmallow apart very safely, without fire. How? Eat it. Your body
functions take it apart and use the energy, the water, and the Carbon.
The energy is used to power your body.
The Carbon combines with the oxygen you breathe in to form the Carbon Dioxide that you exhale.
The water goes into your bloodstream and is used by your body. It becomes part of the 70% water that your
body that is made up of water.
i
The Happy Scientist, 9/8/2014, http://thehappyscientist.com/