Lesson Plan

Physical & Chemical Changes in Matter

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Grade Level:
Fifth Grade
Subject:
Chemistry, Physical Science
Duration:
30 minutes
Setting:
outdoors
National/State Standards:
Utah Science Core Curriculum Topics, Standard One: Students will understand that chemical and physical changes occur in matter.
Keywords:
air quality, ozone, particulates, reactions, physical changes in matter, chemical changes in matter

Overview

In class, students learn the difference between physical changes and chemical changes in matter, and then go for a hike to observe both in nature. They learn about particulate matter in the air, discuss what creates particulates, and discover how scientists measure them. They act out the chemical changes that are destroying ozone in the upper atmosphere and see how scientists measure ozone recovery. Back in class, students mix household items and predict the type of resulting reactions.

Objective(s)

PRE-TRIP ACTIVITY
Matter What?

a. Define matter.
b. Describe the difference between physical and chemical changes in matter

STATION #1
Particulates and Filters

a. Describe at least two sources of particulate matter in the air, and discuss if these particulates result from physical or chemical changes.
b. Give a basic description of how the equipment at the filtering station or transmissometer room operates.

STATION #2
No Zone for Ozone

a. Explain why upper atmosphere ozone is beneficial.
b. Describe what type of reaction physical or chemical is causing ozone depletion.
c. Describe why ground level ozone is harmful to humans.

STATION # 3
As a Matter of Fact

a. Describe the difference between chemical and physical changes in matter.
b. Name one chemical and one physical change that can be observed at Canyonlands
National Park.

POST-TRIP ACTIVITY
It Does What?

a. Describe a physical and chemical change that occurs to matter.
b. Name two indicators of a chemical change.


 

Background

Matter is the “stuff ” of the universe. Everything that has mass and volume, no matter how small, is considered matter. Air, water, rocks, trees, stars, and animals all consist of matter. Matter can exist as a solid, liquid, or gas and can change in many diff erent ways. Physical changes are those in which the weight of the matter stays the same. At the end of a physical change, the substance is still essentially the same. For example, chopping up a carrot or ice melting into water are both physical changes. Dissolving dirt into water would also be considered a physical change because the weight would equal that of the water and the dirt. Chemical changes are those where one or more substances are combined to produce a new substance. Sometimes, the product weighs the same as the ingredients. Sometimes, matter is converted into energy and emitted in the form of heat, light, or sound. At the end of a chemical change, you have a fundamentally new substance. Burning a piece of paper would be a chemical change, as would baking a cake.

Clean air is a common, often under appreciated resource of the public lands of the Colorado Plateau. The Clean Air Act names 160 federal lands with pristine air quality and mandates that air quality at these sites be monitored, preserved, and enhanced. Sixteen of these sites are on the Colorado Plateau; one site is in the Island in the Sky District of Canyonlands National Park. The equipment there measures fine particulate, acid rain, and ozone levels.

Some fine particles, or particulates, are always present in the air. The number of particulates varies; high numbers result in the visible part of air pollution. Particulate sources can be natural or human-caused. They can be the result of both chemical and physical changes in matter. They can include dust and sand from roads, fields, and windstorms, smoke from burning leaves, forest fires, and wood-burning stoves, and exhaust from cars and industries. Particulates remain in the air until gravity slowly filters them out.

Ozone is an invisible gas that is a form of oxygen. High levels of it in the lower atmosphere can cause human health problems and can contribute to the greenhouse effect. Car exhaust, the result of a chemical change in fuel, is a major contributor of ozone to the lower atmosphere. However, ozone plays a positive role in the upper atmosphere. The upper atmosphere ozone layer blocks much of the UV sunlight from reaching the earth’s surface. Normal quantities of UV light are good for such things as plant growth and suntans. But, the increase in UV light that would result from a damaged ozone layer would lead to increased incidences of skin and eye disease in humans and damage to some wildlife and plants.

The single largest factor in the destruction of the ozone layer is a family of chemicals called chlorofluorocarbons (CFCs). This reaction is a chemical change in the ozone molecule. CFC’s were used in manufacturing hundreds of different products, including Styrofoam packaging, aerosol spray cans, and the coolants in refrigerators and air conditioners. Their use has been outlawed in the United States and many countries. Even if all countries quit using CFCs, however, they will linger in the upper atmosphere for decades. At Canyonlands National Park, ozone is monitored at ground level. UV light is also monitored, which indirectly reflects the condition of the upper atmosphere ozone layer. Scientists monitor ozone levels in order to study trends in national parks as well as global trends.
 

Procedure

Extensions

PRE-TRIP ACTIVITY
Matter What?

As a class, mix the ingredients to make a large batch of cookies. As you add each ingredient, discuss what changes the ingredient has gone through, including if those changes were chemical or physical. For example, wheat changed chemically as it was growing, but only physically when it was ground into flour. Bake the cookies in the lunchroom, and discuss that adding the heat of the oven is creating a chemical change in the cookie batter. Eat the assignment.

STATION #1
Particulates and Filters

Have students find the “cleanest” and “dirtiest” plants within a designated area, including a roadside area if possible.) After students work for a few minutes, have them gather and examine the particulate content on their filters by using hand lenses. Discuss how plants filter the air and under what weather conditions (dry) and in what locations (near roads, etc.) they would expect to find the dirtiest plants. Summarize and review.

STATION #2
No Zone for Ozone

Play Silent Killer to reinforce the concept of the hidden nature of ozone depletion (adapted from Fluegelman 1981, 81). Have players sit in a circle; then, distribute and recollect the cards as in the previous game. Instruct the unknown CFC to wink at an ozone when no one else is looking. Instruct any ozone that is winked at to quietly pause a few seconds and then say, “I’ve been destroyed.” All live ozones should watch carefully and try to identify the CFC killer.

STATION # 3
As a Matter of Fact

Have the students write a story from the point of view of a substance undergoing a chemical or a physical change. For example, Joe Nutrient, who is happy in a rock, gets eroded and used by a plant. Stories should be descriptive, in the first person, discuss whether a chemical or physical change is occurring, and have a title.

Additional Resources

Berman, B. (2002) Bad day, sunshine. Discover, 23(2), 33.

Fluegelman, A. (1981). More new games!…and playful ideas from the new games foundation. Tiburon, CA: Headlands Press.

Levine, J. S. (1992). Ozone, climate, and global atmospheric change. Reprint from Science Activities 29, no. 1: 10-16. Washington, DC: Heldref Publications.

Jordan School District and the Utah Office of Education. (2002). Elementary science teacher resource book: State science core teacher text. Salt Lake City, Utah: Utah State Office of Education

National Park Service and National Biological Survey Colorado Plateau Research Station at Northern Arizona University. 1994. Where
the earth is the floor of the sky: Visibility on the Colorado Plateau. Brochure. U.S. Government Printing Office.

National Park Service, Minnesota Environmental Education Board, and the National Parks and Conservation Association. (1989). Biological diversity makes a world of difference. Washington, DC: National Parks and Conservation Association.

Peterson, M. F. (1973). Activities for environmental education: Water, air, soil. Bismark, ND: Department of Public Instruction.

Sherwood, E.A., Williams, R.A., & Rockwell, R.E. (1990). More mudpies to magnets. Rainier, MD: Gryphon House Press.

Storer Camps. (1988). Nature’s classroom: A program guide for camps and schools. Martinsville, IN: American Camping Association.

Vocabulary

Heat, substance, chemical change, dissolve, physical change, matter, product, reactants,
solid, liquid, weight