Photosynthesis Lessons

2 Photosynthesis Lessons: The Effects of Air on Plants and The Effects of Light on Plants
Grade(s): 4-6

L.OL.E.1 Life Requirements- Organisms have basic needs, Animals and plants need air, water, and food.  Plants also require light. Plants and animals use food as a source of energy and as a source of building material for growth and repair.
L.OL.04.15 Determine that plants required air, water, light and a source of energy and building material for growth and repair.

List of Items Needed for Experiement:
water, backing soad, test tubes or syuringes, plastic cups, tweezers, hole punchers, leaves, and soapy water (not pictured: green plastic or glass bottles, and lamp)

                An In-Depth Look at the Key Concepts of Photosynthesis   
                                                                                                                                 (Background Information)

ust like humans, plants need food too.  But, unlike humans, plants can make their own food.  They do this through a process called photosynthesis.  Photosynthesis occurs when plants convert energy from sunlight into a simple sugar, glucose.  This occurs as carbon dioxide and water are taken in, glucose is produced, and oxygen and water are given off.

Glucose is slightly different from the sugar (sucrose) that you put into your tea. Glucose is simpler than sucrose but, contains the same three chemical elements:  carbon, hydrogen, and oxygen.    Different sugars are put together to form starch, which serves as the major food storage for green plants. The carbon needed for photosynthesis comes from carbon dioxide in the air (unless they are aquatic plants, in which case they get it from the water surrounding them).

The hydrogen comes from water, most likely from the soil in which they grow.

They also need other nutrients such as nitrate, sulphate and phosphate. These are sold under the incorrect name “plant food,” when plant food is really the sugars and starches produced in photosynthesis.  A few plants cannot get nitrate out of the soil easily, so they have to eat small animals.  Insects are mainly the type of small animals that are consumed in order to get the nitrogen that they need to grow.

The chloroplasts, small green-pigmented structures within a cell containing chlorophyll, are responsible for the absorption of light that drives photosynthesis. 

Before respiration, plants break down the starch into the glucose that will be needed as the plant respires and uses oxygen like an animal does.  Respiration is often thought of as the opposite of photosynthesis because CO2 and water are formed as energy and oxygen and used.  However, oxygen use in respiration is much less than oxygen production in photosynthesis, so plants are producing oxygen. 


When plants use carbon dioxide and water to make glucose there is a lot of oxygen left over. Here is a word equation:

                        Carbon Dioxide  +  Water ------------------------->>>>  Glucose  +  Oxygen

Here is a summary of the most important information on photosynthesis:

*Photosynthesis requires:
                -carbon dioxide,
                -light energy,

*Photosynthesis produces:
                - oxygen
*Photosynthesis is the conversion of:
                -light energy into,
                -chemical energy

*Photosynthesis is essential for:

*Photosynthesis takes place in:
                -but sometimes in stems, such as in a cactus where the leaves are reduced to spines.

Developmental Relevance to Fourth Graders

         There are few resources available for teachers in Michigan to teach photosynthesis to fourth graders.  Yet these students still need to learn the important elements needed to create photosynthesis and sustain plant life.  This experiment helps students understand what plants need through questioning their background knowledge and inquiry processes, helping feed their intellectually curious minds.  Fourth graders also enjoy making the connections to the “bigger world” which can explain why they also appreciate learning new vocabulary (Wood, 2007).  To start the construction of understanding photosynthesis or at least the pieces that are involved with why plants are living things or green could pose interesting to many fourth graders.  Science always encourages learning new terminology and for fourth graders that can be a good time to introduce the term photosynthesis.  Photosynthesis is a very important vocabulary word for any grade school student to know before they enter middle school and high school as it is more frequently referred to at those grade levels.
        Overall, fourth graders can use this inquiry based experiment to learn about photosynthesis as it encourages them to  physically move around the room and their tables, mentally challenge their brains, and expand their previous knowledge to build new knowledge.
             Wood, C. (2007) Yardsticks: children in the classroom ages 4-14. 3rd Ed.  Northeast Foundation for Children.
                               Turners Falls, MA.

Lesson Plan for Effects of AIR on Plants

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Lesson Plan for Effects of LIGHT on Plants

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Pictures Above from Left to Right, Top to Bottom
Picture 1: Shows how the green plastic pop bottles can be wraped around the light fixture
Picture 2: One cup with the disks is under the green light and other cup is under white light.
Picutre 3. Green light leaf disks after 10 min. (none have risen)
Picture 4. White light leaf disks after 10 min. (4 have risen)
Picture 5. Green light leaf disks after 12 min. (none have risen)
Picture 6. White light leaf disks after 12 min. (5 have risen)

Ways to develop three different experiments from here the disk assay:

1. do a light experiment with room lighting as the control and a clamp on light blasting white light (have to control for heat) as the treatment
2. do a light experiment with white light as the control and green light as the experimental treatment.  Shown in Experiment 2
3. do a carbon dioxide experiment with water as a control and baking soda water as the carbon dioxide treatment.
**Of course controls and treatments should be run simultaneously.
*** Never experiment with too many variables.  Keep it simple.

Photosynthesis Rap Lyrics

You got your chlorophyll and your sunlight too
You got your water and you got your CO2
Put it all together gonna make some food

Food is sugar
Gotta build some starch
Gonna save it up
Til the end of March

Got it all together gonna make some gas
A little bit of oxygen will make us last


Leaves:  Plant Leaves (spinach is recommended), Fresh leaves are best bought from a grocery store
Hole Punches: Craft Stores, Super Stores  (Walmart, Meijer)
Tweezers: Dollar Store, Super Stores (Walmart, Meijer)
Sodium Bicarbonate: Baking Soda bought at a grocery store
Plastic Cups: Grocery, Party Stores, Super Stores (Walmart, Meijer)
Dish Soap: Dollar Store, Super Stores (Walmart, Meijer)
Syringes:  Local Pharmacies about 24 cents apiece.
Lamps:  Hardware Store (shop lights), Pet Shops
100 Bulbs:  Grocery and Super Stores (Walmart, Meijer)
If you choose to use a more native leaf, it will be helpful to contact more local resources such as the state agricultural extension director or agricultural bureau in your area.  They will have tips on how much light, water, and diseases that could effect  plant leafs’ proficiency during the experiments.

Calhoun county extension office contact:
315 West Green Street

Marshall, Michigan
United States

Email Address:
Phone: 269-781-0784
Fax: 269-781-0768

Other MSU extension offices in Michigan:
America Society of Plant Biologist: Compiled a large resource of programs and websites for students and teachers.   A majority of the material is for Secondary education teachers, however, there are plenty of great sources for ideas or references.  There is also a few good K-12 websites.

Fast Plants: Information on purchasing fast plants as well as activities for teachers.

Field Museum and the Evolving Plant: Photosynthesis starting during the Precambrian.  Connections to evolution of plants.

FT exploring science and technology: Informational page on photosynthesis and energy in nature. FT Exploring is a fun award winning site that explores energy and other basic science principles and shows how the same fundamental principles control how things work in nature, living organisms, and human technology.

Green Machine: List of books and internet resources on plant parts and mechanics for K-12 students.

Oxygraphics: Idiosyncratic books on photosynthesis and related topics such as global climate change. Many of those in PDF available for free download.

The Rose Hills Foundation Conservatory for Botanical Science: Huntington Conservatory as put together a great educational website to learn about plants.  Plant Basics is a good place to start and includes figures defining photosynthesis.