Living Environment
Student Work
Biochemistry Unit Lesson 9
pH and Living Things
Name:
Period ______
Laboratory Experience
Worth 90 Lab Minutes
Date :
Bridge
Quiz: Answer all of the following questions based on the information from
yesterday and last night’s homework.
1. In terms of molecules, what would you expect to find in a strong
acidic solution?
2. Give two properties and two examples of acids.
3. Give two properties and two examples of bases.
4. Describe how we would use the pH scale.
5. How would you measure the pH of a solution?
Objective:
Determine the
effect of pH
on living
things.
Essential
Question:
How does pH in
the environment
affect the
survival of living
things?
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Biochemistry Unit Lesson 9
Mini Lesson
Task: You are to develop an experiment to determine the effect of pH on living things. You will
be using Elodea as your “test subject”. You can use any of the materials provided and if there is
anything else you would like, please ask and if I have it I will provide it.
Elodea is a very common waterweed found all over the US. Many people use Elodea
(sometimes called Canadian waterweed or anacharis) to help
maintain balance within their aquariums. Each sprig of this kind of
Elodea have three leaves per whorl around the stalk. It lives
entirely underwater with the exception of small flowers which will
bloom at the surface of the water in which they live. They prefer
environments that have silty sediment and water rich in nutrients.
They grow in a wide range of conditions, from very shallow to very
deep fresh waterways, but for the most part prefer an environment
that is slightly basic due to the nature of many fertilizers having a
basic pH. Many can continue to grow unrooted. It is an important
member of the ecosystems in which it resides. It provides a good
habitat for many aquatic invertebrates and cover for young fish and
amphibians. Waterfowl, especially ducks, as well as beavers and
muskrats eat this plant.
Work Period
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Biochemistry Unit Lesson 9
Effects of pH on Living Things
Exploration
Use this space to record observations that relate to the question being investigated. Also record
researched facts that might relate to the investigation as well.
Question
Record your question that you will be investigating here. It is best to write it in a “Does
__________________ affect ________________? Format so the variables are easy to identify (first
line is always the independent variable, second line is always the dependent variable)
Identify your Variables
Independent Variable:
Dependent Variable:
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Biochemistry Unit Lesson 9
Prediction/Hypothesis
Based on the question that you asked, record your thoughts on what the result will be and why. Use
the “I think ___________________________________, because ______________.” format.
Experimental Design
List the materials that you are going to use and the procedure (steps) you are going to take to test your
hypothesis.
Materials:
Procedure:
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Biochemistry Unit Lesson 9
Data Collection
Use this space to organize and collect your data. Remember, data can be qualitative (descriptions,
words, observations) as well as quantitative (numbers, values). Use both kinds of data when you can.
Organize your data into a table with a title, make a graph whenever you can, and use the variables to
help you do this!
Data Analysis
Put your data into words. This will be a relationship of your variables: what happened to the dependent
variable when you changed the independent variable?
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Biochemistry Unit Lesson 9
Evaluation
This is where you talk about your experiment. Discuss how your results compare to your hypothesis:
do you agree or disagree with your original thoughts and use evidence from your experiment to back
this up. Second, discuss sources of error (at least 2), or things that could have gone wrong in your
experiment. Finally, develop a further investigation question: based on what you found out in this
experiment, what else do you wonder about? Again, use your “Does ________ affect __________”
format for this question.
Summary
Day 1: What data would you need to collect tomorrow in order to support your hypothesis?
Day 2: Answer the EQ. How does pH in the environment effect the survival of living things?
Closing
We used a plant as our example of a living thing and what environment it will live best in. Do
you think if we used an animal, like a fish or an aquatic snail, they would require the same
environmental conditions? Why or why not?
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Living Environment
Student Work
Name:
Biochemistry Unit Lesson 9
Period ______ Date :
Independent Practice
The Impact of Acid Rain
Abstract
Some of the inventions that make our lives easier are also causing pollution. Pollution is the
release of harmful substances into the environment. One form of pollution is acid rain. Acid rain can
damage plants, animals, soil, water, building materials, and people. Scientists have discovered that
burning fossil fuels creates acid rain through air pollution. People burn fossil fuels such as coal and
oil to make electricity. Electricity heats and lights buildings and runs appliances such as televisions
and video recorders. Fossil fuels power our cars, buses, and airplanes. The air pollution created
when these fuels burn does not stay
in the air forever. It can return to the earth as acid rain. And when it does, it may weaken the plant
and animal life it contacts. Acid rain is only one form of pollution that results from burning fossil
fuels. It is one of particular interest, however, because it can be transported over long distances.
Scientists, engineers, and researchers are learning how to measure the amount and effects of
pollution in the air, forests, water, and soil. They are inventing ways to reduce the amount of
pollution that enters the environment and prevent new damage in the future.
Article
Since the beginning of time, humans have learned to make use of many things in nature
such as fire and electricity. From the early times through the Industrial Revolution to the Space
Age, humans have produced inventions that use many of the earth’s varied energy resources to
make living easier. In many cases the energy comes from burning fossil fuels—coal, oil and natural
gas.
Some of the inventions that make our lives easier are also causing pollution. Pollution is the
release of harmful substances into the environment. One form of pollution is acid rain. Acid rain is
any form of rain that is more acidic than normal (with a pH lower then 5.6). Pure water has a pH of
7, normal rainfall has a pH of a bit less than 7, but acid rain can have a pH of about 5.0-5.5, and
even in the 4 range in the northeastern United States.
Acid rain can damage plants, animals, soil, water, building materials, and people. Scientists
have discovered that air pollution from the burning of fossil fuels is the major cause of acid rain.
People burn fossil fuels such as coal and oil to make electricity. Electricity heats and lights
buildings and runs appliances such as televisions and video recorders. Fossil fuels power our cars,
buses, and airplanes. The air pollution created when these fuels burn does not stay in the air
forever. It can return to the earth as acid rain. And when it does, it may weaken the plant and
animal life it contacts. Acid rain is only one form of pollution that results from burning fossil fuels. It
is one of particular interest, however, because it can be transported over long distances. Scientists,
engineers, and researchers are learning how to measure the amount and effects of pollution in the
air, forests, water, and soil. They are inventing ways to reduce the amount of pollution that enters
the environment and prevent new damage in the future.
The smoke and fumes from burning fossil fuels rise into the atmosphere and combine with
the moisture in the air to form acid rain. The main chemicals in air pollution that create acid rain are
sulfur dioxide (SO2) and nitrogen oxide (NOX). Acid rain usually forms high in the clouds where
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Biochemistry Unit Lesson 9
sulfur dioxide and nitrogen oxides react with water, oxygen, and oxidants. This mixture forms a mild
solution of sulfuric acid and nitric acid. Sunlight increases the rate of most of these reactions.
Rainwater, snow, fog, and other forms of precipitation containing those mild solutions of sulfuric
and nitric acids fall to earth as acid rain.
The chemical reactions that change air pollution to acid rain can take from several hours to
several days. Years ago, when smokestacks were only a few stories high, pollution from
smokestacks usually stayed near the ground and settled on land nearby. This caused unhealthy
conditions for plants and animals near the smokestacks. To reduce this pollution, the government
passed a law permitting the construction of very tall smokestacks. At that time, people thought that
if the pollution were sent high into the air it would no longer be a problem. Scientists now know that
this is incorrect. Sending pollution high into the sky increases the time that the pollution stays in the
air. The longer the pollution is in the air, the greater are the chances that the pollutants will form
acid rain. In addition, the wind can carry these pollutants for hundreds of miles before
they become joined with water droplets to form acid rain. For that reason, acid rain can also be a
problem in
areas far from the polluting smokestacks.
The region of the Continental United States most affected by acid rain is the Northeast,
where pH levels of between 4.0 and 4.5 are commonplace. Notably, the most rapid increase in acid
precipitation in the U.S. seems to be in the Southeast, an increase paralleling the expansion of
Southeastern urban and industrial activities that result in sulfur and nitrogen emissions.
West of the Mississippi, rain is generally neutral or even alkaline. Colorado, the Los Angeles
Basin, the San Francisco Bay Area, Spokane, Tucson, and Portland are the known exceptions. In
these locations, as in the Northeast,precipitation ranges from between pH 4.0 to 5.0.
Source: Acid Rain. A Student’s First Sourcebook. EPA, Washington, DC
Answer all of the following questions based on the article and your understanding of chemistry and
biology.
1. Define acid rain:
_______________________________________________________________________________
_______________________________________________________________________________
2. Explain the pH difference between acid rain and pure water:
_______________________________________________________________________________
_______________________________________________________________________________
3. Describe the major cause of acid rain:
_______________________________________________________________________________
_______________________________________________________________________________
4. Why is acid rain of particular interest?
_______________________________________________________________________________
_______________________________________________________________________________
5. What are the main chemicals in air pollution that create acid rain?
_______________________________________________________________________________
_______________________________________________________________________________
6. How long does the chemical reactions take that change air pollution to acid rain?
______________________________________________________________________________
_______________________________________________________________________________
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Biochemistry Unit Lesson 9
7. What did the U.S. government do at first to reduce the pollution from smokestacks?
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
8. How successful was this government action?
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
9. Which region of the Continental United States is the most affected by acid rain?
______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
10. Which region is the least affected by acid rain?
_______________________________________________________________________________
_______________________________________________________________________________
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