Students will use dirty pennies to observe physical change.
- USOE Science
Some good ideas on the USOE science site for ELL students
- Writers Express: A handbook for young writers, thinkers, and
learners, by David Kemper, et.al.; ISBN 0669471658
- Kitchen Science with over 50 Fantastic Experiments, by Chris
Maynard (DK Publishing); ISBN 0-7894-6972-3
Background for Teachers
Each student needs a penny that is no longer shiny. If the pennies
you have are too clean, oxidize the surface in the following manner.
Place all the pennies into a cup and pour vinegar over the top. After
coating them with vinegar, spread the pennies out on a paper towel to dry
overnight. By the time they are dry you will see a green-colored
substance called malachite.
When the salt and vinegar are combined, they form a very small
amount of hydrochloric acid. This acid removes oxidation from pennies.
Removing the copper oxide is a chemical change. The copper molecules
in the vinegar and salt solution settle on paper clips after a period of time,
but wipe off easily. This is not a chemical change. If the cleaned
pennies are allowed to sit without rinsing them off, more malachite
Intended Learning Outcomes
1. Use Science Process and Thinking Skills
Invitation to Learn
Today we are going to do an activity with money and chemicals. The
chemicals are sodium chloride and acetic acid (or salt and vinegar).
- Give each student a dirty penny. Observe pennies. Stress the
importance of using all the senses, except for taste. Students
record observations on the Clean Pennies data sheet.
- Pass out goggles. Students should keep the goggles on until the
cups are put away in step six. Give each pair of students a cup
with a small amount of salt in the bottom. Students place the
pennies in the cup. Allow students to rotate cups. Ask what
changes to the penny they see. (none)
- Add a small amount of vinegar to each of the cups. Allow
students to rotate cups and observe changes.
- Pennies will become bright pink and copper colored. All the
discoloration may not be removed, but most pennies will show a
- Remove pennies and place them on a paper towel to dry.
- Place a paper clip in each cup of vinegar and salt solution. Leave
the paper clip in the solution overnight. After cups are put away,
- Observe paper clips next day. Wear safety goggles to avoid
splash danger. Allow students to remove the paper clip from
solution and handle it. The copper coating will rub off easily.
Ask students if the paper clip’s change to copper-colored was a
chemical or physical change. (It was a physical change. No new
substance was formed. The copper was there all the time—dissolved in the solution.)
- Allow students with special needs to list or draw examples of
chemical change instead of writing a paragraph.
- Make a list of Important Science Words to use in the assigned
- Allow students with special needs to dictate their paragraph to
another student, an aide, or the teacher.
- To introduce the idea of physical properties, have each student
bring an object from home. Each student describes a number of
physical properties, such as color, shape, texture, etc. Other
students take turns guessing the identity of the item.
- Have a mold race! Moisten a slice of bread with a few drops of
water and place it into a Ziploc sandwich bag. Place it in a warm,
dark place. Keep the bag zipped shut after the mold grows—many
people are allergic to mold. Observe the bread once a day and
keep a log of the changes that occur. Many of the changes are
chemical changes. Design an experiment to investigate questions
like: Does white bread or whole wheat bread mold faster? Does
homemade bread or store-bought bread mold faster? Does bread
get moldy faster in a warm environment or cold environment?
Does bread mold faster in sunlight or dark?
- Have students repeat the Clean Pennies activity at home with one
variation—after removing the pennies from the solution, place a
steel screw in the solution instead of a paper clip. They should
see bubbles rising from the thread of the screw, which is another
indicator of chemical change.
- Create a rubric to score the paragraph including attributes such as,
science content, organization, presentation, conventions, and use
of science language.
- Make a T-chart with Physical Changes on one side and Chemical
Changes on the other side. Give students a list of changes to
categorize. Include examples of change from daily life.