Dtse2007:Photosynthesis

Photosynthesis

Demographics

Gender	Age /   Grade	Bio-background Female	17 /  12	Advanced Biology Advanced Chemistry Male	18 /  12	Advanced Biology Advanced Chemistry Female	15 /  10	Biology General Science Female	17 /  12	Honors Biology Chemistry with Lab Advanced Biology Male	17 /  12	Biology Chemistry Earth Science Female	17 /  12	Biology Chemistry Earth Science Female	16 /  10	Biology Male	16 /  10	AP  Biology AP Chemistry Female	11 /  6	General Science Female	12 /  7	Biology General Science Female	13 /  8	Biology General Science Female	13 /  8	Biology General Science

Objectives
 * 1) 	SWBAT identify and describe different types of energy and understand conversion of solar energy to chemical energy.
 * Energy cannot be created or destroyed. It can only be converted from one type to another.
 * Energy is not a “thing”. Energy is the capacity of a system to do work.
 * Understand the difference between Work, Force and Energy.
 * SWBAT define and explain what an autotroph and heterotroph are and their roles in the ecosystem.
 * Autotrophs are the only organisms that can produce their own food.
 * Energy is stored in an autotroph and then transferred to different trophic levels.
 * The interdependence of organisms in a food web.
 * 1) 	SWBAT draw and label the parts of a chloroplast, including chlorophyll pigments and understand their role in photosynthesis.
 * Understand wavelengths, the color spectrum and refraction and absorption of light.
 * 1) 	SWBAT define and explain the equation of photosynthesis (its reactants and products) and various factors that affect the rate of photosynthesis.
 * Emphasize the production of glucose as the purpose of photosynthesis and oxygen as a byproduct.
 * 1) 	SWBAT define and explain the two pathways light and dark reactions (Calvin Cycle).
 * Light and dark reactions are two parts of the photosynthesis equation.

Protocol


 * 1) 	Can you tell me what energy is? Where does energy come from?
 * 2) 	(If they do not mention solar energy) Is light a form of energy?
 * 3) 	What do plants need to survive? Draw it. Why?
 * 4) 	Why do you think they need: water……light……soil. How it happens?
 * 5) 	Do you know where plants get their food? Is it similar to how humans get their food?
 * 6) 	(If they mention Sun) How does the Sun help the plants?
 * 7) 	(If say make food from Sun) How do you think that happens?
 * 8) 	What happens with the plant if you put it in a dark place?
 * 9) 	Why are leaves green?
 * 10) 	Why are plants needed in the environment?

Possible follow up questions: How do you think it happens? Can you tell me what that/it means?

Summary This was the most difficult concept for the students to understand. Every student mentioned the word force; some mentioned work or motion. Typical answers were, “It’s a force…a force that is found in nature”, and “a force, um power and things that move or things that involve moving them”. They seemed to think that energy is a thing that is either created or found in nature. They intuitively knew that there were different types of energy and could name some types but beyond that they were very confused. None of them understood how energy was converted. Some of them had a notion of a “change” or “reaction”. Some of them thought that light itself was the food for the plant and only a few understood that it is used to make food. Instructional ideas: We need to make sure that students understand the difference between energy, work and force, how energy is actually converted and be able to define and explain the types of energy. Most of the students did not understand why plants do photosynthesis. They thought the main reason for the photosynthetic process was oxygen production. They did not understand the idea of a food web or relate other organisms to the role of plants. They mainly referred to a plant’s role as fulfilling our need to breath. Only one student referred to the medicinal benefits of plants. Instruction: The students need to understand the complexity of a food web and the idea of interdependence beyond human beings. Students confused chloroplast with chlorophyll. Most of them knew it could be found in leaves but didn’t understand its role in photosynthesis. Only a few of the students knew the leaves were green because of chlorophyll or chloroplast. Three students knew that photosynthesis took place in chloroplast. These three students mentioned different light waves and something to do with color but couldn’t put it into the why the leaves are green. Instruction: We need to work a bit on the chemistry inside the chloroplast for the students to understand how the conversion of energy is done. Only six out of twelve students knew that glucose is the end product produced in photosynthesis. The products and reactants were not clear and therefore they could not expand on what would affect the rate of the plants production. Most of them understood there was a process and a change involved but couldn’t explain it fully. Instruction: We need to help the students become familiar with describing a chemical equation and the inputs and outputs of the photosynthesis reaction. Also, because of the idea that oxygen seemed to be the “purpose” of photosynthesis, we need to focus on the significance of the glucose production-that plants do it for themselves, not for us or anything else. Instruction: These are terms and ideas the students should be familiar with but they are not part of the enduring ideas of this unit. The kids should understand that the dark reaction does not occur in the dark or only at night but is the second phase of the light reaction and both are needed to produce glucose.
 * 1) 	Energy
 * 1) 	Autotrophs and Heterotrophs
 * 1) 	Chlorophyll in Photosynthesis.
 * 1) 	Photosynthesis equation. Factors affecting its rate.
 * 1) 	Light/Dark reaction: Not part of the interview process.