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Fertilizers, Pestcides and Human Health - Chemistry Lessons

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Big Idea
As Paracelsus stated: “The dose makes the poison.”  The science of toxicology is based on the principle that there is a relationship between an organism’s toxic reaction (response) and the amount (the dose) ingested, inhaled or absorbed.  
Essential Question
What makes a substance toxic?
Learning Cycle
Lesson Title & Description
Objective
Students will:
Class period & week
Engage

Introduction to Toxicology
Students will be introduced to the science of toxicology and the relationship between a toxic reaction (response) and amount of substance (dose), exploring the dose-response relationship.

1. Define the nature of a chemical.

2. Create a system to classify chemicals

1 class period

Explore

Dose makes the Poison
In groups, they will investigate the effect of a chemical (they choose) on the germination of seeds.  They will calculate % chemical concentrations in water, form a hypothesis, and discuss the ethics of using animals in biomedical research.

1. Define a “toxic substance.”

2. Define the “science of toxicology."

3. Differentiate between natural and manmade toxic substances.

4. Explain the dose-response principle.

5. Calculate chemical concentrations in water.

6. Explain toxicological principles that govern the safety of a substance.

7. Analyze toxicological risks versus benefits of a substance based on their understanding of toxicological principles.

3 class periods
Explain

Dose/Response
In groups, as a conclusion to the seed germination experiments, they will investigate the effect of a chemical (they choose) on the germination of seeds and will create a dose-response curve to interpret their observations and evaluate their hypothesis
.

1. Explain the dose-response principle

2. Explain routes of entry

3. Explain acute versus chronic

4. Explain the relevance of exposure frequency, duration, and concentration

2 - 3 class periods

Apply

Toxicology and Blackworms
Students will investigate the potential toxicity of water samples using *California Blackworms.

1. Apply knowledge of toxicology for an environmental study.

2. Make inferences regarding the level of toxicity in each water sample.

3. Create a dose-response graph.

1 - 2 class periods

*Need to order Blackworms from a biological supply company and obtain appropriate consent to conduct an experiment using live specimens.

--Top--


Big Idea
Concentration (dose) determines if a substance is toxic. Many substances considered non-toxic can become toxic if the concentration or type of exposure is changed.
Essential Question
 What products are toxic?
Learning Cycle
Lesson Title & Description
Objective
Students will:
Class period & week
Engage

Toxicity
What substances do you use at home that are toxic?

Students will  input information into an excel document  about products that they use and think are toxic.

Start thinking about what kinds of chemicals they are exposed to in their home.

5 minutes for each student (done prior to the Explore) for a survey..
Explore

What is Toxic?
Students will use a website to find the chemicals present in everyday items using the toxnet worksheet.

1.  Learn how to use the toxnet website to look up the chemicals and hazards in a substance.

2. Define toxicity.

3.  Understand the relationship between concentration and toxicity.


4.  List avenues for exposure to toxic substances.

1 class period
Explain

Toxic Products
Students will make a poster explaining how specific chemicals in the product they researched could be toxic.

1. Explain the relationship between concentration and toxicity.

2.  Explain the various ways to be exposed to a toxin.
1 class period
Apply

 Which are toxic?
Students will use toxnet to determine if a set of substances if ingested or inhaled is dangerous.

1.  Determine if something is inhaled or ingested is dangerous.

1 class period

--Top--

Big Idea
Many pesticides are toxic to people, yet as a population, we rely heavily on them for safety and convenience.
Essential Question
How can the risks versus the benefits associated with pesticides be understood and communicated?
Learning Cycle
Lesson Title & Description
Objective
Students will:
Class period & week
Engage

Pesticide Prevalence
Students will investigate the prevalence of pesticides in their communities by searching their homes, visiting local grocery stores and hardware stores, and talking to extended family and friends. 

1. Read a pesticide label to distinguish the trade name, common name and chemical name.

2. Classify pesticides according to their function.

3. Classify insecticides according to their chemical makeup.

2 class periods one week apart
Explore

“Is Organic Food Worth the Extra Cost?” Part I: Doing the Calculation
Students calculate the amount of pesticide residue in various foods for two pesticides and determine if these levels are safe for human consumption. 

1. Calculate the dose of a pesticide using food intake levels and pesticide residue concentrations;

2. Evaluate the safety of food pesticide residue food intake levels and pesticide residue concentrations;

1 class period
Explain

“Is Organic Food Worth the Extra Cost?” Part II: Compare and Contrast Science Essay
Students read an article about a research study looking for metabolites of these pesticides in children. 

Compare the costs and benefits of organic food versus conventional food.

1 - 2 class periods
Apply

Scientist writes to the Newspaper

Defend their position about whether or not organic food is worth the extra cost.
1 - 2 class periods

--Top--

Big Idea
Given the proper concentration fertilizers can increase the production of many plants, but sometimes at the expense of other organisms.
Essential Question
What is the effect of fertilizer on plants and animals?
Learning Cycle
Lesson Title & Description
Objective
Students will:
Class period & week
Engage
“She ate the whole thing”
Students will work in small groups to determine the severity of Given a scenario involving  toxicity of  a variety of fertilizers, herbicides and pesticides and present their findings on a white board.
Use toxnet to determine the toxicity of a variety of fertilizers, herbicides and pesticides.
1 class period
Explore

Do plant fertilizers affect animals?
Each student group will test the affect various concentrations of miracle grow on an organism.

Use various concentrations of miracle to test for morbidity.
1 class period to set up and 10 minutes of class for 5 days
Explain

Lab Report
Students will write a lab report explaining the results of their experiment.

--
--
Apply
Design an experiment to test the toxicity of  different fertilizers, herbicides or pesticides, on a different organism. --
--

--Top--

Big Idea
Ammonium Nitrate is a useful fertilizer providing nitrogen for plants. It is also a powerful explosive that has caused many disasters.
Essential Question

Is it worth the risk?

Learning Cycle
Lesson Title & Description
Objective
Students will:
Class period & week
Engage

Jekyll & Hyde
During this exercise, students will learn that ammonium nitrate is used as a fertilizer and an explosive

Understand how chemicals can be very dangerous when not treated with care

Week 1

1 class period
Explore

Efficient Fertilizer
During this exercise, students will learn that ammonium nitrate is used as a fertilizer and an explosive

1. Compare different fertilizers and understand their world wide use.

2. Calculate the molar mass and percent nitrogen in the different fertilizers.

Week 1

1 class period
Explain

Stoichiometry
During this exercise, students will learn that ammonium nitrate is used as a fertilizer and an explosive.


Heat of Solution

Students will measure the energy change caused by dissolving one mole of ammonium nitrate in water.

Quantify the relationship between moles and mass.

 

1. Quantify the relationship between temperature, energy and heat

2. During this exercise, students will learn that ammonium nitrate is used as a fertilizer and an explosive.Understand that an endothermic reaction causes a decrease in temperature

Week 1

2 class period
Apply

Is it Worth the Risk?
During this exercise, students will learn that ammonium nitrate is used as a fertilizer and an explosive

Compare the benefits of using ammonium nitrate and the risks.

Week 1

1 class period

PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:


an
NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award

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LOGO - NIEHS Center LOGO - NIEHS

Supported by NIEHS grant # ES06694


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Last update: November 10, 2009
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