Sorting Recyclables
Lesson 1, Activity 1
Physical and Chemical Properties
Name____________________________
Date_______________Bell___________
Essential Question:
Challenge:
What guiding questions will this activity
address?
Answer these questions when the activity is
complete.
Property-
What are some characteristics of your materials you could check for on your substance (even if
you don’t have the right equipment). Work with your partner to generate examples of each.
Observed
1
Measured
Tested For
Examples of Physical Properties
Examples of Chemical Properties
Investigating properties of unknown materials.
Your team will investigate the properties of 4 different unknowns. Record observations in the columns,
be as specific as possible. When testing with the four liquids, use your straw-scoop to place a small
amount in the well, and add a few mL of liquid with the pipette and stir with a toothpick.
When you have finished all of your observations, determine which tests/observations you think represent
physical properties, and which you think represent chemical properties. How do you know?
Unknown Color
Shape of
With
particles
vinegar
(microscope)
With With
iodine water
With
Cabbage
Juice
(pH)
Magnetic IDENTIFY
SUBSTANCE
A
B
C
D
Chemical
or
physical
Property
How do
you
know?
Your group must come up with a good definition of physical and chemical properties. This must include
how you know you have tested for a physical or chemical property.
A physical property is
A chemical property is
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After your unknowns have been identified, use this information – along with your data to answer the
questions below.
1. Which properties are least useful in identifying your unknowns? Why?
2. If you had a mixture of baking soda and salt, what property would allow you to recover the salt,
unchanged? Why? Is this a chemical or physical property?
3.
Would this method allow you to recover the baking soda? Why or why not?
4.
Soup cans often come to a recycling facility with paper labels on the outside. The goal of the facility is
to recover the steel can without the paper or glue. The paper label will not be recycled. Would it be
better to use a chemical property (paper burns, steel cans do not), or a physical property (paper is
soluble in water, steel is not) to accomplish this? Why?
5.
Aluminum scraps need to be separated from number 2 (HDPE) plastic scraps. Both materials are highly
recyclable, and need to be recovered. Would it be better to use a chemical property (Aluminum reacts
with acid, plastic does not) or a physical property (plastic floats in water, aluminum does not) to
separate these materials? Why?
6. In general, do you think it is more useful to use physical or chemical properties to separate materials
that can be recycled from each other? Why?
3
7.
In general, do you think it is more useful to use physical or chemical properties to separate
contaminants, or non-recyclables from recyclables? Why?
8.
Complete answers to the guiding questions at the beginning of this worksheet.
Sorting Recyclables
Lesson 1, Activity 1
Physical and Chemical Properties
Formative Assessment
1.
Name____________________________
Date_______________Bell___________
The following were observations in a student’s lab journal. Was the student observing a physical or
chemical property? What actual property are they observing? How do you know?
Observation
Physical or
Chemical?
Property observed?
How do you know?
Ice changed to water if you
let it sit on the counter.
Aluminum foil is smooth and
silver colored
A hamburger cooks on the
grill.
Steel wool burns if you light
it with a match
Chocolate gets really hard
when you put it in the freezer
Milk gets lumpy if you add
lemon juice to it.
Sugar, flour and eggs
combine to make a delicious
cake when heated.
My desk is 28 inches tall
The bumper on my car is all
rusted.
2. The following all represent physical changes (changing the physical property of a material).
A piece of paper is cut with scissors.
Candle wax melts to a liquid.
The mass of a lump of clay is reduced when a piece is removed
Salt is dissolved in water.
Which of the following is true about a physical change?
a. New substances or materials are produced during a physical change.
b. New substances are NOT produced, the substances are the same after a physical change.
3. To observe a chemical property, a chemical change must occur (new substances produced). To see if a
piece of paper has the chemical property of combustability (will burn in oxygen), you must actually try to
burn it, producing carbon (ash), water vapor, carbon dioxide – the material is no longer paper. Think
about the lab, and the chemical properties and changes here. What are some clues, observations that
might indicate that a chemical change has occurred?
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