Implementing the Module

The six lessons in this module are designed to be taught either in sequence for two or more weeks (as a replacement for a part of the standard curriculum) or as individual lessons that support or enhance your treatment of specific concepts in middle school science. The following pages offer general suggestions about using these materials in the classroom; you will find specific suggestions in the procedures provided for each lesson.

What Are the Goals of the Module?

Chemicals, the Environment, and You is designed to help students develop the following major goals associated with scientific literacy:

• to understand a set of basic scientific principles related to chemicals, human health, and the study of toxicology;
• to experience the process of scientific inquiry and develop an enhanced understanding of the nature and methods of science; and
• to recognize the role of science in society and the relationship between basic science and human health.

What Are the Science Concepts and How Are They Connected?

We have organized the lessons to form a conceptual whole that moves students from an introduction to chemicals and toxicology (Chemicals, Chemicals, Everywhere), to an investigation of the effect of various doses of chemicals on seed germination (The Dose Makes the Poison), to a discussion of the relationship between dose and response that can be represented by a dose-response curve (Dose-Response Relationships). Once students have experienced the process of toxicology testing, they discuss how individual responses to chemicals can vary (Individual Responses Can Be Different), and how knowledge about chemicals can be used to assess and manage risk from chemical exposure (What Is the Risk?). Finally, students consider how their understanding of how chemicals can affect human health can help them make decisions related to personal and public health (Environmental Hazards). The chart below, Conceptual Flow of the Lessons, illustrates the sequence of major concepts addressed by the six lessons.

Conceptual Flow of the Lessons

Lesson	Learning Focus	Major Concept
Lesson 1 Chemicals, Chemicals, Everywhere	Engage*: Students express prior knowledge and become engaged in the study of toxicology.	Everything in the environment is made of chemicals. Both naturally occurring and synthetic substances are chemical in nature. People are exposed to chemicals by eating or swallowing them, breathing them, or absorbing them through the skin or mucosa, and they can protect themselves from harmful chemicals by blocking these routes of exposure.
Lesson 2 The Dose Makes the Poison	Explore: Students explore the response seeds have to different doses of chemicals. The Explore phase gives students a common set of experiences upon which to begin building conceptual understanding.	The total amount of chemical that is administered to, or taken by, an organism is called a dose, and the effect a chemical has on a living organism is called the response. The effect a chemical has on a living organism is related to dose and the resultant concentration of the chemical in the organism. Toxicity tests enable toxicologists to learn about responses of living organisms to doses of chemicals.
Lesson 3 Dose-Response Relationships	Explain: Students express their conceptual understanding of the laboratory investigation in their own words and using graphs.	Dose and response are related and can be represented by a dose-response curve. Data from toxicology testing can be represented by a dose-response curve, from which scientists can describe the threshold and potency of chemicals.
Lesson 4 Individual Responses Can Be Different	Explain/Elaborate: Students broaden their conceptual understanding and apply what they have learned in a new context.	The variety of responses among organisms that get the same dose of chemical is due to individual susceptibility. Dose and individual susceptibility play roles in all situations involving chemicals, including those involving medicines and caffeine.
Lesson 5 What Is the Risk?	Elaborate: Students extend the module's concepts in a different activity to help them apply scientific terms and concepts in appropriate ways.	People can make some choices about chemical exposure; however, some exposure is controlled at a level other than an individual one. Collective groups of people, such as communities and governments, seek to control chemical exposure on a community or global level.
Lesson 6 Environmental Hazards	Evaluate: Students demonstrate their understanding of concepts and performance of skills.	People can use their understanding of the science of toxicology to identify potential sources of harm to human health from chemicals in the environment. They can use their knowledge to propose possible means to eliminate or reduce exposure to environmental toxic agents.

*See How Does the 5E Instructional Model Promote Active, Collaborative, Inquiry-based Learning?

How Does the Module Correlate with the National Science Education Standards?

Chemicals, the Environment, and You supports teachers in their efforts to reform science education in the spirit of the National Research Council's 1996 National Science Education Standards (NSES). The content of the module is explicitly standards based: Each time a standard is addressed in a lesson, an icon appears in the margin and the applicable standard is identified. The chart below, Content Standards: Grades 5–8, lists the specific content standards that this module addresses.

Content Standards: Grades 5– 8
Standard A: As a result of activities in grades 5–8, all students should develop abilities necessary to do scientific inquiry and understandings about scientific inquiry.	Correlation to Chemicals, the Environment, and You
Design and conduct a scientific investigation.	Lessons 2, 4
Use appropriate tools and techniques to gather, analyze, and interpret data.	Lessons 2, 3, 4
Develop descriptions, explanations, predictions, and models using evidence.	Lessons 2, 3, 4, 6
Think critically and logically to make the relationships between evidence and explanations.	Lessons 3, 4, 6
Communicate scientific procedures and explanations.	Lesson 3
Use mathematics in all aspects of scientific inquiry.	Lessons 2, 3, 4
Develop understandings about scientific inquiry.	Lessons 2, 4, 6
Standard B: As a result of their activities in grades 5–8, all students should develop an understanding of properties of matter.
There are more than 100 known elements that combine in a multitude of ways to produce compounds, which account for the living and nonliving substances we encounter.	Lesson 1
Standard E: As a result of their activities in grades 5–8, all students should develop understandings about science and technology.
Perfectly designed solutions do not exist. All technological solutions have trade-offs, such as safety, cost, efficiency, and appearance.	Lessons 1, 5
Technological solutions have intended benefits and unintended consequences. Some consequences can be predicted, others cannot.	Lessons 1, 4, 5
Standard F: As a result of their activities in grades 5–8, all students should develop an understanding of
personal health	Lessons 4, 5, 6
natural hazards	Lessons 1, 5, 6
risks and benefits	Lessons 1, 5, 6
Standard G: As a result of their activities in grades 5–8, all students should develop an understanding of the history and nature of science.
Understand science as a human endeavor.	All lessons
Understand the nature of science.	All lessons
Understand the history of science.	Lesson 5

Teaching Standards

The suggested teaching strategies in all the lessons support teachers as they work to meet the teaching standards outlined in the National Science Education Standards. The module helps teachers of science plan an inquiry-based science program by providing short-term objectives for students. It also includes planning tools such as the Conceptual Flow of the Lessons chart and the Suggested Timeline for teaching the module. Teachers can use this module to update their curriculum in response to their students' interest in this topic. The focus on active, collaborative, and inquiry-based learning in the lessons helps teachers support the development of student understanding and nurture a community of science learners.

The structure of the lessons in this module enables teachers to guide and facilitate learning. All the activities encourage and support student inquiry, promote discourse among students, and challenge students to accept and share responsibility for their learning. The use of the 5E Instructional Model, combined with active, collaborative learning, allows teachers to respond effectively to the diversity of student backgrounds and learning styles. The module is fully annotated, with suggestions for how teachers can encourage and model the skills of scientific inquiry, as well as the curiosity, openness to new ideas and data, and skepticism that characterize science.

Assessment Standards

Teachers can engage in ongoing assessment of their teaching and of student learning using the variety of assessment components embedded within the module's structure. The assessment tasks are authentic: They are similar in form to tasks in which students will engage in their lives outside the classroom or in which scientists participate. Annotations guide teachers to these opportunities for assessment and provide answers to questions that can help teachers analyze student feedback.

How Does the 5E Instructional Model Promote Active, Collaborative, Inquiry-based Learning?

Because learning does not occur through a process of passive absorption, the lessons in this module promote active learning: Students are involved in more than listening and reading. They are developing skills, analyzing and evaluating evidence, experiencing and discussing, and talking to their peers about their own understandings. Students work collaboratively with others to solve problems and plan investigations. Many students find that they learn better when they work with others in a collaborative environment than they can when they work alone in a competitive environment. When all this active, collaborative learning is directed toward inquiry science, students succeed in making their own discoveries. They ask questions, observe, analyze, explain, draw conclusions, and ask new questions. These inquiry experiences include both those that involve students in direct experimentation and those in which students develop explanations through critical and logical thinking.

This view of students as active thinkers who construct their own understanding out of interactions with phenomena, the environment, and other individuals is based on the theory of constructivism. A constructivist view of learning recognizes that students need time to

• express their current thinking;
• interact with objects, organisms, substances, and equipment to develop a range of experiences on which to base their thinking;
• reflect on their thinking by writing and expressing themselves and comparing what they think with what others think; and
• make connections between their learning experiences and the real world.

This module provides a built-in structure for creating a constructivist classroom: The 5E Instructional Model. This model sequences the learning experiences so that students have the opportunity to construct their understanding of a concept over time. The model takes students through five phases of learning that are easily described using five words that begin with the letter "E": Engage, Explore, Explain, Elaborate, and Evaluate. The following paragraphs illustrate how the 5Es are implemented across the lessons in this module.

Engage

Students come to learning situations with prior knowledge. This knowledge may or may not be congruent with the concepts presented in this module. The Engage lesson provides the opportunity for teachers to find out what students already know or what they think they know about the topic and concepts to be developed.

The Engage lesson in this module, Lesson 1: Chemicals, Chemicals, Everywhere, is designed to

• pique students' curiosity and generate interest,
• determine students' current understanding of the concepts of chemicals and routes of exposure,
• invite students to raise their own questions about chemicals and human health,
• encourage students to compare their ideas with the ideas of others, and
• allow teachers to assess what students do or do not understand about the stated outcomes of the lesson.

Explore

In the Explore phase of the module, Lesson 2: The Dose Makes the Poison, students explore the effect different doses of chemicals have on seed germination. This lesson provides a common set of experiences within which students can compare what they think about what they are observing and experiencing.

During the Explore lesson in this module, Lesson 2: The Dose Makes the Poison, students

• interact with materials and ideas during the seed investigation;
• consider different ways to solve a problem or answer a question;
• acquire a common set of experiences with their classmates so they can compare results and ideas;
• observe, describe, record, compare, and share their ideas and experiences; and
• express their developing understanding of the effects of chemicals on seed germination orally and by making graphs.

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