Green is Great!

PDQ1

Fantastic photosynthesis with databot™!

Overview

Grades:
Time:
Subject:

5-8
5-15 minutes
Life Science

The magic ingredients for life on earth are CO2, sunlight, and water! View the process of photosynthesis first hand using databot™, light, and your scientific skills!

Background

Photosynthesis is a process in plants activated by light. In the presence of light, with water and carbon dioxide, photosynthesis takes these ingredients and, among other things, forms glucose – a simple sugar that becomes fuel to sustain the plant. Plants are the only living organisms capable of obtaining carbon straight out of the air by absorbing CO2.

Light, the activating ingredient, is an electromagnetic radiation with wavelengths visible to our eye. Visible light is one of the key ingredients in photosynthesis. You probably know that plants absorb carbon dioxide and give off oxygen, but did you know this only happens in the presence of light? Light+Water+CO2 = Oxygen for us to breathe and the carbon required to form glucose (fuel) for the plant. A great deal for us all!

databot™ has a CO2 sensor that can help us “see” plants consuming CO2. It also has a light sensor that can tell us the intensity of light in lux – a unit of measure for light. Are you curious to see how light, plants, and CO2 all come together?

Let’s explore photosynthesis further with databot™!

What You'll Need

IOS or Android smart device with Bluetooth Low Energy (BLE) to connect to databot™
databot™ + Phypox App installed on your IOS or Android device
Gallon sized zip lock freezer bag
Plastic straw
A clamp light that can be positioned at different heights for varying light intensity
Assortment of green, broadleaf plants to experiment with. We selected romaine, red lettuce and spinach for our experiments assuming they would be easily sourced. Other plants from your garden are fun to experiment with, and you may be surprised at some of the results you get!

Objectives

By completing this experiment and conducting the scientific observations associated with it you will master the following knowledge! Good luck science explorer!

Plants conduct photosynthesis to provide themselves with the carbon needed to grow and survive.
Plants are considered producers because they harvest the carbon necessary for growth and repair from CO2 in the air.
Consumers are animals and other life forms that obtain the carbon they need for growth and repair by consuming carbohydrates formed by producers in photosynthesis.
Carbon Dioxide (CO2) is:
- An invisible and odorless gas.
- Absorbed by plants during photosynthesis.
- The source of carbon for plants.
Light intensity is measured in lux and effects the rate of photosynthesis.
Photosynthesis requires sunlight, CO2, and water to take place.
Plants store carbon in sugar molecules called glucose, a carbohydrate that can be consumed by people and other organisms to provide them with carbon.
Scientific sensors allow us to measure the scientific world around us with better precision and accuracy.

Important Terms

Carbohydrates: Sugars containing oxygen, hydrogen, and carbon.

Carbon: A highly abundant, incredibly important chemical element with the symbol C that, due to its unique ability to form bonds, serves as a common element to all known life. All life that we know of we refer to as “carbon-based” and our human body is made up of approximately 18.5% carbon.

Carbon Dioxide (CO2): A colorless, odorless gas comprised of oxygen and carbon that is naturally present in the air you breathe and is absorbed by plants in photosynthesis.

Chlorophyll: a pigment in plants that enables them to absorb and use light energy in the process of photosynthesis.

Consumers (heterotrophs): Consumers are living organisms that acquire their carbon from means other than photosynthesis, such as eating plants and absorbing the carbohydrates stored in the plant.

Glucose: A simple carbohydrate, a sugar, that is used as a source of energy by plant and animal cells.

Light: A form of electromagnetic radiation capable of being seen by the human eye. Stars like our sun give off radiation, sunlight, that provides energy for the process of photosynthesis in plants.

Lux: The lux is unit of measurement used to express light intensity as perceived by the human eye. For example, a dark overcast day might read 100 lux, classroom lighting 500 lux, a sunny day 25,000 lux, and direct sunlight 100,000 lux.

Oxygen (O2): A molecule formed of two oxygen atoms and is a major component (21%) of the air we breathe. When we breathe, we extract oxygen from the air and absorb it into our bloodstream. Our cells then use oxygen to convert food to energy!

Photosynthesis: The chemical process in plants, driven by sunlight, that absorbs carbon dioxide from the air and combines it with water to provide the carbon needed by the plant to form complex molecules that enable it to grow and repair itself. Glucose, its source of energy, is one of these complex molecules.

Producers (autotrophs): Plants are considered producers due to their unique ability to produce complex molecules from carbon gained through the process of photosynthesis. They draw the carbon supply needed to survive from CO2 molecules in the air!

Stomata: Tiny pores found on plant leaves used for gas exchange. Carbon dioxide enters the plant through the stomata and oxygen is released.

Water: A chemical substance that covers over 70% of Earth’s surface and is essential to all living things. Water is an important component of photosynthesis as it, sunlight, and carbon dioxide work together to produce carbohydrates, the source of energy for the plant.

Prep (5 Mins)

This is a simple and fun activity in which you will put databot™ in a closed container with plant leaves and expose the leaves to light while watching CO2 consumption with databot™ You will vary the intensity of the light during different runs to see if it affects the CO2 consumption.

You will need an airtight container. Here we are using a large zip lock bag, some spinach, and a drinking straw.
Make sure your databot™ is fully charged.
Your light source should be able to be adjustable to test different light intensity levels, measured in lux, against CO2 consumption. You can vary light intensity by changing the angle of the light or the distance from the light to the plant.
What do you think will happen as you vary the levels of light intensity?

PDQ 1 (10 mins)

Terms and Process

Look at this simple image representing the process of photosynthesis and think about these important terms as you conduct your experiment. You are about to see some of these in action using databot™!

Carbon Dioxide
Carbohydrates
Oxygen
Water

Of particular importance is the concept of carbon – an element critical to life on Earth. Plants are the only living organisms on our planet capable of acquiring carbon from thin air!

Procedure

Place your charged databot™ in your bag or container with your plant leaves as shown. Spread the leaves out so they are nice and flat to receive lots of light!
Select the CO2 + Lux experiment setting in Phyphox.
Exhale some air into your bag with the straw and seal it. You want to get a level of at least 1000 ppm or higher. databot does not read below 400 ppm so you need some room to work.
Set your light up, turn it on, and take note of the light intensity in lux. You should be able to change the height of your light source which will vary the light intensity for each of your 3 runs.
Let the CO2 level in the container stabilize which may take a few minutes. When you see a steady rate of decrease in CO2 you can begin.
Stop Phyphox and clear your data to prepare for your experiment!
Write down the starting CO2 level. Now begin your 1 minute run and begin your Phyphox recording. Run the test for 60 seconds and stop. Write down the ending CO2 value at 1 minute. Note: You can run your experiment longer if desired.
Now repeat this twice more, moving your light source to reduce the lux reading for each run. Let’s see if the light intensity makes a difference in CO2 consumption!

Deep Thoughts with databot

What do you notice about your PPM levels?
Does changing the light intensity make any difference?
What does this mean in the real world? Explain what impact your findings have on how CO2 is absorbed by plants.
What do you think is the most important ingredient in photosynthesis?
Carbon is extracted from the CO2 in photosynthesis, and used to build other substances, including glucose, a fuel that gives us energy. What would an animal look like that could extract carbon and food straight from the air? Can you imagine that?

Great Work!

Great work! Another PDQ coming up! Ready. Set. Go!

Next Step, Another PDQ!

Educator Info

Prep: (30 Minutes)

Study the background information in the Overview and familiarize yourself with the learning objectives and terms for this activity and what you would like to emphasize.
Conduct the PDQ yourself, at different light intensities, before conducting it for your class. Different plants provide different results so check first to make sure your class will go smoothly!
Review the guiding questions to help guide the student experience.

Objectives:

Understand:

Plants conduct photosynthesis to provide themselves with the carbon needed to grow and survive.
Plants are considered producers because they harvest the carbon necessary for growth and repair from CO2 in the air.
Consumers are animals and other life forms that obtain the carbon they need for growth and repair by consuming carbohydrates formed by producers in photosynthesis.
Carbon Dioxide (CO2) is:
- An invisible and odorless gas.
- Absorbed by plants during photosynthesis.
- The source of carbon for plants.
Light intensity is measured in lux and effects the rate of photosynthesis.
Photosynthesis requires sunlight, CO2, and water to take place.
Plants store carbon in sugar molecules called glucose, a carbohydrate that can be consumed by people and other organisms to provide them with carbon.
Scientific sensors allow us to measure the scientific world around us with better precision and accuracy.

NGSS

MS-LS1-7. Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism.
MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem. (Grades 6 – 8)
MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved. (Grades 6 – 8)

Cross Cutting Concepts

Systems may interact with other systems; they may have sub-systems and be a part of larger complex systems.
Models can be used to represent systems and their interactions.
Energy and Matter. Matter is conserved because atoms are conserved in physical and chemical processes.
Within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter.
Cause and Effect. Cause and effect relationships may be used to predict phenomena in natural or designed systems.

Engineering Practices

NGSS Practice 4: Analyzing and Interpreting Data
Excerpt: When possible and feasible, students should use digital tools to analyze and interpret data. Whether analyzing data for the purpose of science or engineering, it is important students present data as evidence to support their conclusion.

Disciplinary Core Ideas

LS1.C: Organization for Matter and Energy Flow in Organisms. Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy.

Misconceptions:

Glucose is the only substance formed in the process of photosynthesis. In reality, very little glucose is produced but it is often portrayed as the sole product. Carbon extracted from CO2 is used to build and repair tissue in the plant as well as create glucose. The bulk of a plant’s tissues are actually made up primarily of materials drawn from the air which is a remarkable thing for students to contemplate.

Guiding Questions:

What happens when we change light intensity?

Why?

Why do you suppose plants are called producers and other living organisms are called consumers?

What is your favorite food? Was the process of photosynthesis involved in it in any way?

Additional Resources:

References

Awesome sunlight and leaf image by dmarr515 from Pixabay

Photosynthesis diagram from Wikimedia Commons under CC 4.0.

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