What changes our minds? (Toxicants) Toxicants, exposure, and the environment
Introduced through video interviews of researchers on the University of Illinois campus, this unit concentrates on the role of the environment in exposure to chemicals and their effects. Students play a board game that demonstrates the biomagnification of toxicants in food chains and develop a hands-on investigation on the toxic effects of certain alga on the waterflea Daphnia. Students gain insight into their exposure to toxicants while developing a standard curve for chemical analysis and learn about cell structures through the context of various toxicants and effect on cellular function in a card-matching case study activity. The unit wraps up in a summative presentation or debate which allows students to cultivate a balanced perspective on the benefits and costs of chemicals.
Lesson 1: What changes our minds?
The purpose of this lesson is to introduce the driving question: What changes our minds? Through a series of discussions, students generate different types of answers to this question using a series of videos in which people of different backgrounds address the question from varying viewpoints. Through their own discussions and others' responses to the same question, students begin to answer this question from both brain and mind perspectives. Students begin to learn an important concept in psychology and science in that over time and based on experiences, people's understandings and conceptions can and do change.
Note: The unit, “What changes our minds? Foods, drugs, and the brain,” shares a common theme with the unit “What changes our minds? Toxicants, exposure and the environment”. This common theme is the investigation of how exogenous chemicals affect organisms. Lessons 1 and 2 for both units are nearly identical, and beginning with Lesson 3 the units branch off separately with one covering concepts related to toxicants, exposure and the environment and the other covering concepts of foods, drugs, and the brain.
This Lesson 1 is nearly identical to Lesson 1 in the unit “What changes our minds? Food, drugs, and the brain.” The only difference between these two lessons is the homework assignment in which students complete a survey of the kinds of chemicals they come into contact with. In this unit, “Toxicants, exposure, and the environment” the homework survey contains primarily items that contain chemicals that would be considered toxicants. In the unit “Foods, drugs, and the brain”, the homework survey contains a list of items that would primarily be considered drugs.Updated in 2014Associated Media:
Lesson 2: How do we define what changes our minds?
This lesson introduces students to commonly held definitions and categorizations of “drugs” and “toxicants.” Students investigate their own ideas about these words through a categories game where they group terms into the drug, toxin, toxicant, and poison categories based on initial reactions and then a series of questions. After whole class definitions are generated, a video is shown of the University of Illinois scientists explaining their definitions of “drugs” and “toxicants” and why they define these words as such. Based on the video and subsequent homework reading, students develop a better understanding of the difference between drug and toxicant.
Note: The unit, “What changes our minds? Foods, drugs, and the brain,” shares a common theme with the unit “What changes our minds? Toxicants, exposure and the environment”. This common theme is the investigation of how exogenous chemicals affect organisms. Lessons 1 and 2 for both units are nearly identical, but beginning with Lesson 3 the units begin to branch off separately with one covering concepts related to toxicants, exposure and the environment and the other covering concepts of foods, drugs, and the brain.Updated in 2014Associated Media:
Lesson 3: How does the environment magnify our exposure to toxicants?
In this lesson students investigate the role of environment in exposure to toxicants. In Activity 1, students and teacher play a board-based Bio Bay game in which they play the roles of Anchovies, Tuna, and Fishing Boat (humans) to model the biomagnification of a toxicant with each trophic level. To gather more information, students read about how mercury enters food chains and a case study of a community affected by mercury poisoning. Using this information, students analyze data collected from the game to observe trends of biomagnification as toxicant concentration increases with each higher trophic level. Students also evaluate the game as a model for biomagnification by discussing its strengths and limitations. In Activity 2, students use recent news articles to gain perspective on how most people are exposed to toxicants today. The lesson concludes with student groups creating public service announcements that communicate the concept of biomagnification and the dangers of consuming high levels of mercury through fish.Updated in 2016Associated Media:
Lesson 4: Where are toxicants and how much are we exposed?
This lesson introduces students to the ways in which they are exposed to toxicants in their daily lives. In the previous lessons, students learn about what defines a toxicant and how toxicants affect a variety of ecosystems. This lesson first introduces how we are exposed to environmental toxicants by asking students to evaluate how different media reported the results of a research study on BPA exposure (from eating soup from BPA-lined cans). Then, students learn about how their own exposure can be measured. They first create a dilution series using food coloring to build their skills in analyzing and interpreting dilution series data. Then, they determine the quantity of BPA in everyday products with a common biological assay, ELISA, that uses spectrophotometry. Students gain skills in the generation and use of a standard curve that requires the use of basic algebra.Updated in 2015
Lesson 5: How can an environmental toxicant affect Daphnia?
In this lesson, students conduct an experiment to examine the effect(s) that a common aquatic algaecide, copper sulfate, has on Daphnia, a small zooplankton found in freshwater lakes that is used as a model organism in scientific research. Using their experimental data, students draw conclusions about the safety of using copper sulfate as a way to control algae overgrowth in aquatic ecosystems and recommend a safe concentration (if there is one) of this algaecide to use in ponds.Updated in 2015
Lesson 6: Toxicants in action: What changes the cell?
In this lesson students explore a variety of toxicants and chemicals that illustrate potential cellular mechanisms of action. By the end of the lesson, students should be able to create a concept map/schematic of basic cellular processes and how these processes can be modified by external chemical influences (i.e. toxicants). This lesson is intended to support the discussion of the biological activity of toxicants (how do chemicals change the cell?).
This is a two-day lesson involving both the toxicant information and the integration of these data into a working understanding of the cell and points of influence/regulation. Students start the lesson by developing a visual conceptualization of the neuron (as a picture of a cell, or a schematic of neuron function). Then students are asked to interpret information about the cellular targets of chemicals (Toxicant Data Sheets). Finally, students integrate these ideas into a working model of how a neuron’s function can be regulated by external chemicals.Updated in 2015
Lesson 7: If it's harmful, why do we use it?
Through this lesson, students learn a historical perspective of why BPA is present in our society and investigate the different positions of those vested in regulating (or not) the use of BPA. First, students read various news articles highlighting the debate over the use of BPA, from the perspective of the mass media. Then, they are placed in “expert groups” where they take on a specific role and conduct research to determine that particular role’s position on the use of BPA. Once these groups have developed a position statement, or research statement, students jigsaw to form a new group with a member of each role represented, similar to a Congressional Panel who takes each position into account before making a decision to regulate a toxicant. Based on the information presented, this new group will have to decide whether or not BPA should be regulated and explain why based on evidence and reasoning presented in the research reports. Students then reflect on “what changes our minds about a particular substance?” using what they have learned throughout the toxicant unit.Updated in 2014