Green Chemistry

Introduction

This unit is about relationships and cycles. The relationships involve green chemistry. This topic can be very interesting due to the fact that it has so many different components that you can research and look at. So, as I walk around on a cool brisk day contemplating my writing, I ask myself what will be beneficial to my students. Should I think green as everyone else does? So I started to ponder images of green places that are scenic and beautiful. A park in my city came to mind. The park is Point State Park. It is full of trees where all of the three rivers meet, the Ohio, Allegheny and the Monongahela. As I walked through this park looking at the leaves in their autumn state, I thought about oxidation in its proudest form. How it shows off in different phases and cycles. About thirty percent of the world is forested, and trees are very popular in urban and rural settings. I know I have at least two trees in my yard. I will be discussing trees in several different ways, but the main point is that, without the infrastructure of an ecosystem, this topic would not exist. For example, a tree interacts a certain way with the soil, an animal that may use it for shelter, the amount of sun available to it, the amount of water available and the climate. A tree has abiotic and biotic features; sunlight is abiotic and the tree is biotic. So, I guess from this you can tell that trees will be important in this unit. Decomposition is often referred to as composting. Composting will also be discussed in this unit.

To begin with, there were two Pennsylvanians who had an interest in what I will be writing about. The first is Joseph Priestley, a British born theologian, philosopher, educator and political scientist. He wrote over 150 works. He discovered oxygen. He tried to explain the oxidation theory by using phlogiston, but this was incorrect. Nonetheless, he took the current theory and tried to make something from it. He focused on the scientific thought on combustion from the 1700's. He tried to understand oxygen through respiration. He experimented with a lit candle by covering and uncovering it with a bell jar. Then after the candle went out, he put a piece of mint plant in the bell jar to see if it would grow. His conclusion was that plants helped cleanse the atmosphere. After many different tests, he determined that only the green parts of plants cleaned the air (http://wikepedia.org/wiki/Joseph_Priestley) ¹. (Accessed July 6, 2009.) The second person from my state and very near to my city is Rachel Carson. She was a writer, a scientist and an ecologist. She enjoyed working with natural habitats. She wrote pamphlets on natural resources and edited scientific journals. She wrote a children's book named "Preserving a Sense of Wonder" and a very popular book about pesticides called "Silent Spring". The reason I choose Rachel is because she has a homestead trail. I intend to visit this place with my class and see demonstrations on composting. They also have a Sense of Wonder Hike with examples of organic gardening using native plants. I will be discussing her in this unit. Both she and Joseph will be discussed in relation to trees and ecological systems.

The most important science of the sciences I believe is biochemistry. I sat listening to Gary W. Brudvig, a Eugene Higgins Professor of Chemistry, Biochemistry and Molecular Biophysics, talk about pollution prevention by way of green chemistry. This discussion went into the molecular structures and the periodic chart and common chemical reactions that affect our daily lives related to polluting and conserving. I enjoyed taking in all of this information and I couldn't wait to get to our next meeting. This is what I want for my students, to feel excited and curious about biochemistry as I do. Oh well! Back to the biochemist; this type of chemist is the chemist of the living world. Plants and other living things use the basic chemical compounds to live their lives. Biochemists look at the molecules in a living thing. They also look at the cycles that create those molecules. When you put these three individuals together, Rachel, Joseph and Gary, you get a clear idea of what science is in its broadest sense.

Why oxidation? I teach half the semester about trees. This content is part of my science class that I teach two periods a week per year. The curriculum that is used is FOSS Full Options Science Systems. So how do I tie in green chemistry with trees? Plants are at the base of all living organisms. So we know all the physical parts of a tree. Let's learn its function. My student's demographics consist of several factors. They are kindergarteners who are very curious. I teach in a relatively brand new school five years old to a predominantly African American population in an urban setting. It is a technology-equipped school environment. This unit will be taught over a three-month period using one of my science periods that is forty five minutes in length. I find that my students are very curious and want to learn. My belief is that all students must be motivated to learn and it's my job as teachers do it, and this includes socioeconomic, gender, race and learning ability. Learning styles are different for every individual and I plan to incorporate activities that will meet the various learning styles in my classroom. The FOSS curriculum that I use fosters integration of science stories, exploration, discussion and language development. I will focus on the same principles while developing this unit. Assessing the students will be in three categories. They are content knowledge, investigation and explanation. I will talk about these more in the strategies section of this paper.

The subject green chemistry has twelve principles. In this unit we will focus on three. The first one is that it is better to prevent waste than to clean up after it is formed. The second one is that chemical products should be designed to preserve efficacy of function while reducing toxicity. The third one is to design chemicals and products to degrade after use: design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment. I will be teaching on these three principles through the use of trees. There will be three specific topics related to trees. The three are the photosynthesis cycle, air pollution and composting. The main motivation will be how we can help with controlling air pollution. The carbon cycle is part of the larger cycle called photosynthesis. In this cycle, a great many things are happening. This is studied under the title of a biochemist. In biochemistry, you are studying the living world. Plants and other living things use basic chemical compounds to live their lives. In this part of chemistry, a chemist looks at the molecules in a living thing. They look at the cycles that create the compounds. The cycles that repeat themselves allow for us to live on this earth. So as a biochemist, we will be looking at photosynthesis.

The carbon cycle as I stated is part of a bigger cycle called photosynthesis. Carbon dioxide is an odorless gas. The cycle just like other cycles of give and take are in perfect balance. An example of this cycle is when people inhale oxygen and then exhale carbon dioxide. This is the carbon/oxygen cycle. How do you relate this to trees? Trees let off oxygen and take in carbon dioxide. All living things need oxygen to live. All living things use carbon dioxide. This is how trees make their own food. Living things are joined by a natural balance. They are joined by energy and other living material. There is a balance between oxygen and carbon. Also, a good way of saying this is when people inhale O ₂ they exhale CO ₂, the plants use that CO ₂ as humans use O ₂. This is why trees let off oxygen to balance the CO ₂ they have taken in.

First of all green plants are autotrophic and self-nourishing with the help of energy from the sun, and also water, nutrients from the soil and carbon dioxide. From this point on, I will call it by its chemical name CO ₂ (carbon dioxide). All life is connected in a very delicate balance called ecosystems. All living things do one of three things: produce, consume or decompose. A tree takes on all of these things in its own special way. They produce oxygen, O ₂. And they consume CO ₂. And they decompose through the weathering process and eventually can be used for composting. Now back to this cycle. I will explain it from the photosynthesis standpoint. In order for trees to survive, they need a supply of CO ₂. Photosynthesis is the process by which plants transform water and carbon dioxide into carbohydrates using the energy of sunlight. Sunlight provides energy to create a reaction. There are two phases of photosynthesis. These are called the light reactions and the dark reactions. The light reactions store light energy in chemical form and the dark reactions use the stored energy to form sugars. A chemical in the leaves make these reactions possible. The chemical is called chlorophyll. The chlorophyll absorbs the light and gives the leaves their green color. The captured energy is used to build carbohydrates known as sugars. Along with the sunlight, plants take water from the soil. The process is CO ₂ + H ₂O = chlorophyll/light energy = (CH ₂O) + O ₂. The oxygen produced replenishes the oxygen that was used. This process is the most important biological process on earth. Chlorophyll is a catalyst. This means that it helps chemical reactions take place. (The Columbia Encyclopedia, Sixth Edition/2008.) ²

How does this work? Trees are like busy factories. The main production is in their leaves; the transportation of raw material is done through the roots. The soil contains water and minerals. This is where the roots of a tree live. The roots get tiny hairs on them. This is where the absorption of water takes place. The stems transport this water and material to other parts of the tree. There are different types of tubes in the stems; one transports water and minerals and the other transports food from the leaves to other parts of the tree. Leaves are mostly flat; this gives them a wide surface to absorb the sun. The more leaves, the more light a tree absorbs. Did you know that it is estimated that a full-grown maple tree has over 100,000 leaves. I guess this is why it grows so tall. A leaf has many parts. The top layer is like a sunroof to let in the sun. Inside of a leaf, so much goes on. CO ₂ passes through tiny holes that you cannot see. They are called stomata. These stomata have other cells that watch out for the stomata holes to make sure that not just anything passes through. When they are open gases can pass in and out; when they are closed nothing can pass through. This is how it is run and then to the chloroplast and so on. Photosynthesis keeps this world alive by providing fuel by which we get energy, providing oxygen to burn the fuel and keeps the world's climate in balance. The balance would be aided by having trees in everyone's backyard.

(Carbon Cycle/Photosynthesis. Wikimedia Common-NASA, Encyclopedia.com) Accessed July 27, 2009.

Air Pollution

The purpose for writing this unit is air pollution. I want my students to help with stopping air pollution by planting trees. Clean air or lack of it can cause many problems. It can affect the balance that I spoke of when discussing ecosystems such as in photosynthesis. Air pollution is the action of the environment contaminated with manmade waste into the air. It includes all contaminants found in the atmosphere. They can be in the form of gas or particles. It can be indoor or outdoor. The ozone formed at breathing altitude is bad and is affected by spraying aerosols. Combustible such as barbecues or propane space heaters are not good for the air. Dust, pollen, fungus and viruses are not helping with eliminating air pollutants. Here are some facts about the air we breathe. The air we breathe is composed of nitrogen and oxygen, CO ₂, H ₂O vapors and argon. The earth's air has its own contaminants. Some factories release other harmful gases, which are called green house gases. The green house gases cause the earth's heat to be trapped, raising the temperature so high that it causes global warming. They also injure the health and environment. There are four important pollutants. They are carbon dioxide, carbon monoxide, hydrocarbons, and particulates. These gases directly affect the environment. There are also others that may interact with these. Regulating these pollutants is important and that is why the Environmental Protection Agency was developed; this agency oversees the laws that monitor the environment. Some of the laws are listed below www.epa.gov .

(Accessed July 10, 2009.)

The EPA has been in the forefront of keeping the environment under control. Grant you, we should do more, and with green chemistry developing, there will be more done for the environment. The acts with the asterisks are the ones that have impact on this unit. Without these acts, trees would not be so important around the world. The trees help keep pollution down by trapping pollutants that are in the air. Also, having these regulations helps with cutting down on diseases. Common illnesses in developing countries are respiratory diseases. Respiratory diseases are caused by a combination of factors. These factors can be genetic or environmental. Air pollution may trigger some effects of a respiratory disease. I know in my city of Pittsburgh, Pennsylvania, we were known for our steel mills and even named our football team after them. The steel mills made everyone prosper, but they were polluting the city. Now some of the local residents that have been there all their lives are experiencing respiratory illnesses. One of the major combinations of those diseases is COPD - Chronic Obstructive Pulmonary Disease. This is a combination of emphysema and bronchitis. This illness was formerly related to coal miners, but now people who have never worked in the mines are coming up with this disease. In children, one of the major diseases is asthma. This is also affected by the air and can be caused by air pollutants. I know on some very humid days children with these types of diseases cannot come outside.

There are some improvements that have happened to decrease air pollution. We in America have cut back on air pollution through new automotive and fuel regulations. With different manufacturing going on, fewer pollutants are going into the air. Lead that use to be so heavy in the air is greatly decreased. Pollution has declined in major cities. I would hope that this tree unit will also assist in some small way with cleaning the air. Some of the things trees help with are they settle and trap particles and dust and they absorb dangerous gases. They also keep it cool when it's warm.

Composting

Composting is a great way to recycle from a tree. This concept came to mind because it creates a cycle of its own related to trees. There are three processes that occur within composting. They are microbiological, chemical and physical. The carbon bond is broken down in the presence of oxygen and moisture. Composting occurs in a closed bin and the heat makes the process last longer. It is a process that occurs when the leaves (organic waste) are decomposed by soil microorganisms. Compost is usually mixed with other soils to improve the quality of soil. It adds nutrients for plant growth. The major benefit of composting is that the organic content of compost changes the soil structure to hold oxygen, minerals and water. It is also a natural fertilizer. During the composting process, the material oxidizes, breaking down organic matter into proteins and carbohydrates. The proteins break into nitrates that can be used by plants to make chlorophyll. The carbohydrates break down into simple sugars, organic acids and CO ₂. The compost then goes through the roots and provides nutrients for the tree (www.wikipedia.org/wiki/compost/) ³. (Accessed July 10, 2009.)