A
Discovery Lab for Classroom Science Detectives
Developers:
Tom
Davenport
Edwin Forrest Elementary School
Philadelphia School District
Philadelphia, Pennsylvania
Bob
Stremme
Longstreth Elementary School
Centennial School District
Warminster, Pennsylvania
Dr.
Allen Marks
Building Products Research
Rohm and Haas Company
Springhouse, Pennsylvania
Anne
DeMassi
Building Products Research
Rohm and Haas Company
Springhouse, Pennsylvania
Grade
Level:
All
elementary grade levels (as adapted)
Discipline:
Physical
Science
Goals:
Upon
completion of this lesson students will be able to:
- use
the scientific method to determine the properties
of various kinds of paints.
- identify
the differences between water-based and solvent-based
paints.
- collect
data in appropriate qualitative or quantitative forms.
-
use charts and graphs as a means of organizing data.
-
use collected data to identify paint samples that
are not properly labeled.
-
work in scientific teams.
-
use proper science safety techniques while working
with chemical substances.
Background:
Investigating
the properties of paint is a fun way to see how everyday
materials are designed for specific uses. Paint is used
for two main purposes: to decorate and to protect. Properties
like gloss, color, and hiding are important for decoration.
Properties such as resistance to stain, scrubbing, and
weathering are important for protection. The properties
of paint depend on the ingredients in paint. In this
experiment, students can explore how these properties
are measured and can use the difference in properties
to distinguish one paint from another.
Latex
paints are suspensions of mineral and polymer particles
in water. Solvent-based paints are suspensions of mineral
particles in a polymer solution in an organic solvent.
The particles are very small and can only be seen with
a powerful microscope. The polymer is often called a
"binder" because it acts as glue to bind the
mineral particles together. The binder contributes to
gloss, stain resistance, scrub resistance and weatherability.
The mineral particles impart color to the paint and
contribute to hiding and hardness in the dried paint
film. The most common pigment used in paints is titanium
dioxide (TiO2). This pigment is white and
provides very good hiding. It is also used in colored
paints along with other minerals that impart the color.
There are a variety of other minor ingredients, generally
called "additives". These additives contribute
to properties such as viscosity (flowability), tendency
to settle, freeze/thaw stability, mildew resistance,
and many other properties. In this series of experiments
the student will experience paints with different and
sometimes non-intuitive properties (such as paints that
are thick but do not hide well). Using the Scientific
Method, they can measure these properties and then use
them to identify an unknown paint.
Suggested
Format for Lessons:
Lesson
1
Unit
introduction
Lesson
2
Safety
rules
Lesson
3
Prepare
dry paint samples
Lessons
4 - 15
Paint
Tests (Choose which tests to perform and in which order.)
Odor
Use
the proper technique to discern that wet paint looses
its odor as it dries; determine that water based
and oil based paints have a discernable odor
Dry Time
Define
dry time; test wet paint samples as they dry over a
period of time.
Surface
Tension
Define
surface tension; evaluate surface tension on wet paint
samples as they dry.
Gloss
Define
high gloss, semi gloss, and flat; learn how to evaluate
dry paint samples for their gloss.
Hiding
Define
hiding; test dry paint samples for their hiding properties.
Acid/Base
Prepare
and use red cabbage indicator to determine the pH of
dry paint samples
Presence
of Starch
Use
iodine to determine if dry paint samples the presence
of starch in dry paint samples.
Metal
Marking
Define
metal marking; test dry paint samples for metal marking.
Viscosity
Define
viscosity; measure the viscosity of wet paint samples.
Staining
Define
stain; determine the stain resistance of dry paint samples.
Density
Define
density; measure the density of wet paint samples.
Scrubability
Define
scrubability; test dry paint samples for scrubability.
Lesson
16 - Performance Based Culminating Activity
Students
will identify a "Mystery Paint" sample from
among all the paints studied using their data and repeating
any tests as necessary.
Materials
Group
I - Water Based School/Hobby Paints - all white
A Washable
Tempera
B Non-washable
Tempera
C Hobby
Acrylic Paint
D Fingerpaint
Group
II - Solvent Based Paint - all white
E Oil
Base Primer (Behr)
F Oil
Base Exterior Gloss (Duron)
G Oil
Gloss (Rustoleum)
Group
III - Water Based House Paints - all white
H Latex
Exterior Primer (Behr)
I Latex
Hi Gloss Enamel (Behr)
J Latex
Exterior Flat (Behr)
K Latex
Interior Flat (Behr)
Group
IV - Historical Paints - all white
L Milk
Paint (Mass. Milk Paint Co.)
* Whitewash
(homemade) * not tested
Instant
Coffee
Jelly Rulers
Food Coloring
Toothpicks
Mustard
Permanent markers
Paint Stirrers
Iodine
2-L soda bottle caps
Cereal Boxes
Eye Droppers
Wax Paper
Coins
Paint Brushes
Cabbage
Ketchup
Paper Towels
Wooden Paint Stirrers
Plastic Cups
Plastic Gloves
Notes
to the Teacher:
1.
These labs can be completed independently of each other
and in any order. In order to use the prepared materials
to the maximum effect perform different tests on the
same dry paint sample, doing the destructive tests last.
Be aware that many of the experiments call for dry paint
samples, which must have at least 24 hours drying time.
The labs are written with the directions directed to
the students.
2.
For safety reasons you may want to prepare the red cabbage
indicator ahead of time, and/or control the use of the
iodine, even dropping it on the paint yourself.
3.
These tests were conducted on 12 different varieties
of paint. It is suggested that to gain the optimum number
of differences among the paints, limit the testing to
a maximum of 5 types of paint. You will need to assign
labels to the paints ahead of the lesson (A, B, C, D,
and E). The latex and solvent-based paints used in this
experiment were purchased at Home Depot. The
hobby / school paints were purchased at a craft store,
A.C. Moore.
4.
The experiments can be performed as a class, in small
groups, and/or individually.
5.
The experiments will go faster if all of the boards
are prepared ahead of time by you, or a select group
of students.
6.
The best results can be obtained by using paints from
the different groups listed above. We recommend selecting
one or two paints from each of the four groups. (For
health reasons you may want to eliminate the solvent-based
paints.) It is also possible to get good results from
paints within a group, such as: the four paints in the
hobby/school group, the three paints in the solvent-based
group, or three paints in the water-based House paints
(note that paints J & K give very similar results
and should not be used together.)
7.
Each student or group of students need to keep a Research
Portfolio that can be used to store all of the collected
data, charts, graphs, and paint journal.
8.
Be sure to prepare dry mystery paint samples ahead of
time for the culminating activity. These samples are
not marked with the letters that were used throughout
the unit, but need to be coded so that the teacher will
know the identity of the mystery paint.
9.
Challenge your students by asking them to control variables
by applying the same force and same angle to the dry
paint samples while performing the tests.
10.
Whitewash is listed as one of the historical paints.
It was not used in this testing. It is included as a
possibility and a recipe for homemade whitewash is listed
in the appendix. Because whitewash is so different from
the other paints it is worth exploring and also used
as a curriculum link between science and history.
Lesson
One - Unit Introduction
1.
Introduce unit by asking students a series of questions:
-
What are paints used for?
- What kinds of paint have you used before?
- Why can't soap and water be used to clean up all
types of paint?
Direct students to answer in their "Paint Journal"
- which can be a separate section in their science notebook,
or even a separate booklet. The paint journal, unit
data, charts and graphs can be put into a research portfolio.
Discuss student responses.
2.
Ask students to list any questions that they have about
paint.
3.
List the paints, the letters that have been assigned
to them, and the tests that will be studied in this
unit. Ask students to copy this information into their
paint journals for use as a reference.
4.
List the materials that the students will need to bring
to school.
Lesson
Two - Safety Rules
1.
Since the students will engage in activities that could
be messy and potentially hazardous, the teacher must
help the students become aware of the following cautions:
- Safety
glasses, clothing covering, and plastic gloves need
to be worn while working with these materials. A large
plastic trash bag can be used to cover clothing by
cutting a hole in the bottom for the student's head,
and holes in each side for arms. In place of gloves
plastic sandwich bags held with rubber bands can be
used to cover the hands.
-
Care must be taken in the storage and disposal of
all materials, especially paints. MSDS (Materials
Safety Data Sheets) are available for the paints that
you will purchase. This information is either listed
on the container, or can be obtained from the manufacturer.
In some cases MSDS sheets can be accessed via the
Internet. Unused paint needs to be disposed of in
a safe manner that will not pollute the environment.
Check with local regulations on how this is handled;
this information may be available in the municipal
section of the phone book. It is suggested that disposable
brushes and containers be used for solvent-based paints.
-
When the wet paints are used be sure to ventilate
the room.
-
Some students may encounter breathing difficulty because
of asthma, allergic reactions, etc. when the wet paints
are used. Most of the testing can be arranged on dry
paint samples to alleviate this problem.
2.
Post safety rules on chart paper and have students write
rules in paint journals. These rules can be offered
by the teacher or by individual students and/or groups.
Suggestions:
-
Safety glasses must be worn at all times.
-
Plastic gloves are to be worn when handling wet paint
samples.
-
Open windows when using wet paint samples.
-
Leftover paint in containers and on brushes must be
disposed of properly.
3.
Assign individual students or groups to gather information
and report back to class on the following safety topics:
-How
are leftover paints, brushes, and paint containers
safely disposed of in this school? in this local community?
-What
information is included on the MSDS sheets that come
with the paint samples, and how can this information
be used for safety.
Lesson
Three - Dry Paint Samples Preparation
Dry
paint samples must be prepared ahead of time in order
to complete many of these tests. Depending on the tests
chosen, one sample can be used for multiple tests. For
example, one dry paint sample on a cereal box can be
used to test gloss, hiding, acid/base, starch, scrubability
and staining. Tests such as gloss and hiding, that do
not have the potential to destroy the paint sample,
need to be completed before the other tests are performed.
This lesson may be completed ahead of time for the students,
or during the beginning of the unit by the students.
1.
Cut out the fronts and back of cereal boxes. (You may
want to ask the students to bring in the cereal boxes
already cut) Decide how many paint samples you will
put on each cereal box. Use the permanent marker to
label appropriate sample letters.
2.
To ensure that each sample has the same amount of paint
applied in the same manner the following technique should
be used. Within the rectangle:
- Apply
the brush strokes horizontally stroking from left
to right.
- Cover
these brush strokes with new strokes vertically from
bottom to top.
- Cover
these brush strokes with new strokes horizontally
from right to left.
Lessons
Four - Fifteen Paint Tests
The
worksheets for these paints tests are written for the
students to complete and are to be assigned by the teacher
based upon the tests selected.
Test
for Odor
Problem
Can
wet paint be identified as water based or solvent based
by its odor?
Hypothesis
I
think that different types of paint can/cannot be identified
by their odor because:
___________________________________________
Materials:
Wet
Paint Samples
Procedure:
1.
As part of this test you must use the proper technique
for testing a substance for smell. First, smell the
cap or lid container after you have carefully removed
it from the paint container. Second, holding the container
near, but not right under the nose, waft (gently wave)
the odor towards you, using your hand to cup the air
above the container.
2.
Use the wet paint samples to determine odor. Write down
a descriptive word for the sample. If working with a
group see if agreement can be reached on which word(s)
to use for each sample.
Data:
Paint
Sample____ ___________________________
Paint
Sample____ ___________________________
Paint
Sample____ ___________________________
Paint
Sample____ ___________________________
Paint
Sample____ ___________________________
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Dry Time
Problem:
What
kind of paint dries fastest?
Hypothesis:
When
paint samples are painted onto cereal boxes I think
that sample _____ will dry the fastest.
Materials:
cereal
boxes
paint samples
paint brushes
permanent marker/ruler
disposable plastic/rubber gloves or plastic bags
Procedure:
1.
Divide the cereal boxes into paint sample areas and
mark the areas with the letters used for the paint samples.
2.
Use the paint brush to paint the sample area with the
technique used to prepare the dry paint samples.
3.
By lightly touching a gloved finger (or use plastic
bag over hand) begin checking the paint
samples at five minutes intervals and record their state
as:
W
= wet - wet paint sticks to glove
T
= tacky - paint does not stick to glove but is sticky
to touch
D
= dry - paint has completely dried, is not sticky
at all
Data
for Dry Time, in minutes
Dry
10
15 20 25 30 35 40 45 50 55 60 Time
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Surface Tension
Problem:
What
kind of surface tension do the paint samples have?
Hypothesis:
When
wet paint samples are dropped onto wax paper I think
that sample will have the highest dome (greatest surface
tension).
Materials:
paint
samples
wax paper
cereal box
tape
eye droppers
permanent marker/ruler
Procedure:
1.
Cover a cereal box panel with wax paper and use the
permanent marker to mark a section for each paint sample.
2.
Use an eye dropper to place a drop of paint in each
section.
3.
Observe the surface tension. The rounder, more dome-like
the drop, the higher the surface tension- Using the
following rubric describe the appearance of the paint
drop as it dries.
3
= a dome appearance
2
= a semi-flat appearance
1
= a flat appearance
0
= can't form a drop.
4.
Check results 15 minutes after the paint has been dropped,
and after 4 hours.
Data
for Surface Tension 15 minutes 4
hours
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Gloss
Problem:
Which
paint's gloss best reflects an image?
Hypothesis:
When
looking for the clarity of my name as it reflects off
the painted surface I think that paint sample _____
will reflect it the best.
Materials:
Dry
Paint Samples on Cereal Boxes
White Poster Board or index cards
Thick Black Marker
Procedure:
1.
On a small piece of white poster board or index card
print your first name in large block letters, making
the printed letters dark and thick.
2.
Hold the cereal box and your name board vertically at
a 45-degree angle to each other. This works best with
the boards held at arm's length, catching as much light
as possible. Look to see how much of a reflection of
your printed name can be seen in the paint.
3.
Using the following rubric describe the gloss of each
sample.
3
= letters can be clearly seen - High Gloss
2
= letters can be seen but are clouded or faded
- Semi Gloss
1
= no reflection can be seen - Flat
Data:
Paint
Sample ________ Gloss ________
Paint
Sample ________ Gloss ________
Paint
Sample ________ Gloss ________
Paint
Sample ________ Gloss ________
Paint
Sample ________ Gloss ________
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Hiding
Problem:
What
kind of paint does the best job of hiding what is underneath
of it?
Hypothesis:
When
the printing on the cereal boxes is covered with the
white paint I think that paint ____________ will do
the best job of hiding the letters and colors.
Materials:
Dry
Paint Samples on the front of cereal boxes (best results
if you use all of the same brand cereal fronts or backs.)
Procedure:
1.
Place the dry paint samples all at the same distance
from you. Carefully look for evidence of letters showing
through the white paint. If the same brand of cereal
box has been used for each of samples try to use the
same words or section of the box to evaluate.
2.
Use the following rubric in order to evaluate the hiding
properties:
4 = Letters cannot be seen at all
3 = Shadows seen, individual letters not recognizable
2
= Letters can be seen under the paint, most words
can be read
1 = Letters/words can be easily read
0
= Paint sample does not adhere to cereal box
Data:
Paint
Sample ________ Hiding ________
Paint
Sample ________ Hiding________
Paint
Sample ________ Hiding________
Paint
Sample ________ Hiding________
Paint
Sample ________ Hiding________
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Acid/Base - pH of a substance
Problem:
Are
dry paints samples basic or acidic?
Hypothesis:
If
I test the dry paint samples with red cabbage indicator
I think ________________ are acidic; ________________
are neutral; and ________________ are basic. (fill in
sample letters)
Materials:
red
cabbage
eye dropper
dry paint samples on cereal boxes
non-corrosive container
distilled water
Procedure:
1.
If red cabbage indicator has not been provided follow
these directions. In a non- corrosive container place
red cabbage leaves torn into little pieces. Fill the
container to the top with red cabbage pieces. Carefully
pour boiling water over the leaves, filling the container.
Allow the container to cool to room temperature. Strain
the red cabbage solution, discarding the leaves. You
will be left with red cabbage indicator that has a purple
color. Be sure to keep this solution refrigerated. When
finished with the indicator it can safely be discarded
down the drain.
2.
With the eye dropper place a drop of red cabbage indicator
on each paint sample.
3.
Observe the results. If the drop stays the same purple
color the pH of the paint sample is neutral. If the
drop turns a red color the pH of the paint sample is
acid. If the drop turns a blue/green color the pH of
the paint sample is base. Using the following rubric
record the data:
P
= purple R = red B
= blue/green
Data:
Paint
Sample A ______
Paint
Sample B ______
Paint
Sample C ______
Paint
Sample D ______
Paint
Sample E ______
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Presence of Starch in a Substance
Problem:
Is
starch present in the dry paint sample?
Hypothesis:
If
I test the dry paint samples with iodine I think samples
____________________ contain starch.
Materials:
iodine
dry paint samples on cereal boxes
eye dropper
Procedure:
1.
Be aware that iodine must be carefully handled. Your
teacher may choose to drop the iodine for you.
2.
With the eye dropper place a drop of iodine on each
paint sample.
3.
Observe the results. If the drop stays the same brownish
color there is no starch in the paint. If the drop turns
purple/black color that is an indication that a starch
is present in the paint. Using the following rubric
record the data:
P
= purple/black Br
= brown
Data:
Paint
Sample A ______
Paint
Sample B ______
Paint
Sample C ______
Paint
Sample D ______
Paint
Sample E ______
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Metal Marking
Problem:
Which
paint sample will best withstand metal marking?
Hypothesis:
After
using a nickel to metal mark each of the dry paint samples
I think that paint sample ________________ will show
the fewest metal marks.
Materials:
Dry
paint samples on wood surfaces
nickel
Procedure:
1.
Paint a wood surface with each of the paint samples,
following the directions of your teacher. If wood paint
stirrers are not available you can also use tongue depressors,
or pieces of flat wood trim. Let paint dry thoroughly.
2.
Hold the nickel between your thumb and pointer finger.
Using the edge of the nickel gently rub the dry paint
sample three times. Use this technique on each paint
sample, using the same force and angle each time.
3.
Using the following rubric record the metal marking
on each of the samples:
0
= no visible marks
1
= light metal marks
2
= medium metal marks
3
= dark metal marks
Data:
Paint
Sample A ______
Paint
Sample B ______
Paint
Sample C ______
Paint
Sample D ______
Paint
Sample E ______
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Viscosity
Problem:
What
paint sample has the highest viscosity?
Hypothesis:
If
5 paint samples are placed on a vertical piece of wax
paper covered cardboard, I think that sample ________________
will flow down the slowest (highest viscosity).
Materials:
paint
samples
wax paper covered cardboard
ruler
permanent markers
2 liter soda bottle caps
stopwatch
Procedure:
1.
Cover a piece of cardboard with wax paper, taping the
ends onto the back.
2.
On the wax paper covered cardboard mark two lines in
the center of the board 10 cm apart. Draw a target circle
slightly larger than the size of the cap placed 5 cm
above the top line. Label the circle with the letter
of the paint sample . Prepare a board for each of the
paint samples that you will test.
3.
Place the same amount of paint into each cap. Pour as
much of the paint onto the circle as possible, scrapping
out the paint from the cap, if necessary.
4.
Quickly stand the board upright at a 90 degree angle
and begin timing the paint sample as it crosses the
first line, stop timing when it crosses the second line.
Stop all timing after
five minutes. Record the results for each paint sample.
5.
Repeat the experiment five times. Calculate the averages
of the five tests for each paint sample and record the
data on the chart.
Data:
Paint
Samples
A B C D E
Test
1
Test
2
Test
3
Test
4
Test
5
TOTAL
AVERAGE
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Stain
Problem:
Which
paint is the most stain resistant?
Hypothesis:
After
staining the paint sample with 5 substances I think
that paint sample _________ will resist stains the best.
Materials:
Quarters
Instant coffee
Ketchup
Mustard
Grape jelly
Red food coloring
Coffee filters
2-L soda caps
tweezers
Permanent Markers
Dry paint samples
Procedure:
1.
For each stain that will be tested draw a circle about
the size of a quarter on the dry paint sample. Do not
crowd the circles on the boards. Use a permanent marker
to draw the circles and label the type of stain that
will be used under it.
2.
Prepare the coffee solution by combining 2 g of instant
coffee with 50 g of water. The rest of the staining
materials are used full strength.
3.
Cut circles the size of quarters out of the filter paper.
You will need these for the coffee and food coloring.
Using tweezers dip a filter circle into the coffee.
Carefully place the saturated filter on the correspondingly
marked circle. Cover with a soda bottle cap so it does
not dry out. Begin timing for 30 minutes. Repeat this
procedure with food coloring.
4.
Place a small amount of mustard in the circle. Rub gently
with your finger until the circle is completely filled.
Begin timing for 30 minutes. Repeat this procedure with
the ketchup, and jelly.
5.
After 30 minutes has elapsed carefully lift off the
filter papers. Using a damp paper towel gently rub the
other staining substances off of each circle.
6.
Using the following rubric to evaluate the staining
effect on the paint:
0 = no staining
1
= light staining
2
= medium staining
3 = severe staining
4
= staining material removed paint coat
Data
Jelly Mustard Coffee Ketchup
Coloring
Sample
A
Sample
B
Sample
C Sample D
Sample
E
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Density
Problem:
What
is the density of paint?
Hypothesis:
When
I measure the density of 5 different paints, sample
_______ will have the greatest density.
Materials:
disposable
cups
scale
calculator
water paints
Procedure:
1.
If your scale can be set, place the cup on the scale
and set to zero. If you cannot reset scale to zero with
the cup on it, weigh the cup while it is empty and subtract
that weight from your total of the cup filled with paint
each time. Try to use a volume of 15 to 25 ml.
2.
To get your base line, fill the container with water
and weigh it. The weight of the water will equal the
volume of the container. Use the marker to indicate
a fill line that you will use each time and mark all
of the cups with the same line.
3.
Weigh each sample and divide the weight of the paint
by the volume of the container. Be sure to reset your
scale zero each time.
4.
Record your results.
Data:
Weight
Volume Density
Water
1
Sample
1
Sample
2
Sample
3
Sample
4
Sample
5
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Test
for Scrubability
Problem:
What
happens when I scrub different dry paint films?
Hypothesis:
When
I scrub each of the dry paint samples with a toothbrush,
sample ________ will be the most scrub resistant.
Materials:
dry
paints samples on wood
toothbrush
plastic cups
gloves or plastic bags
plastic or newspapers
Light Duty cleaner (Ajax or Dawn dish liquid)
Heavy Duty cleaner (409 or Fantastic)
Procedure:
1.
Protect the work surface with plastic or newspapers.
Lay out the dry paint samples. Protect your hands by
wearing gloves or using plastic lunch bags.
2.
Prepare the materials used for scrubbing. The 409 Cleaner
and the Fantastic are used straight out of the container.
Place a little of each in a plastic cup. The
Ajax is mixed with water. Prepare by mixing 3 parts
Ajax to 1 part water. The Dawn dish liquid is prepared
as a 5% solution. Ask your teacher for help in preparing
this solution.
3.
Dip toothbrush into 409 solution. Brush back and forth
over the paint sample. Each back and forth counts as
one stroke. Count the strokes needed to totally remove
paint from the wood surface. Gently wipe surface with
damp cloth as needed in order to check the paint sample.
Repeat with all of the samples and cleansers.
4.
To be consistent the same person should test all of
the paint samples using the same toothbrush each time,
applying the same amount of pressure on each stroke.
Each person in the group should test the samples and
come up with a group average.
5.
Using the following rubric to evaluate the scrubability
of the paint - the number of strokes needed to totally
remove paint from the surface:
100md
= after 100 strokes there was medium damage
100ld =
after 100 strokes there was light damage
(number)
= number of stokes needed to totally remove paint
Data
409 Ajax Dawn Fantastic
Sample
A
Sample
B
Sample
C
Sample
D
Sample
E
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Lesson
16 - Culminating Activity
Problem:
Can
unlabeled paint samples, Mystery Paint Samples, be identified
by their properties?
Hypothesis:
Based
upon data already collected I think that the sample
received is Paint Sample _______.
Materials:
All
of the materials used in the previous lesson.
Mystery
Paint sample prepared ahead of time and supplied by
teacher.
Procedure:
1.
Use the wet and dry samples that have been assigned.
If necessary prepare new sample boards.
2.
Prepare a master chart that combines the results of
all the tests performed so far.
3.
Determine which tests need to be performed in order
to identify the paint sample.
4.
Using the directions previously given perform any tests
that need to be repeated.
5.
Record the data and compare with the master chart
6.
Draw your conclusions and name the mystery paint.
Data:
Test Paint
Sample that Matches the Mystery Paint
Odor
Dry
Time
Surface
Tension
Gloss
Hiding
Acid/Base
Starch
Metal
Marking
Viscosity
Staining
Density
Scrubability
Results:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Conclusions:
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Extensions:
Literature, Writing, Math, and Social Studies
Literature
Help
the students discover chapter two from Mark Twain's
The Adventures of Tom Sawyer where Tom tricks
the town boys into whitewashing Aunt Polly's fence,
which is "thirty yards of board fence nine feet
high." Not only that, but they "pay "
Tom for the privilege of doing his work. Tom collects
an assortment of prizes, among them an apple core, a
kite in good condition, and a dead rat on a string.
Writing
Basing
the activity on Tom Sawyer whitewash painting experience,
challenge the students to find a similar activity. How
could they "trick" friends into doing some
chores? Perhaps they could be "tricked" into
using a riding power mower and would be willing to cut
grass in exchange for new sports cards? Ask the students
to present this experience as a short story, or write
and act it out as a play.
Math
These
experiments produce an abundance of facts. Challenge
the students to arrange the facts in multiple charts
and graphs. Assign each group a type of graph (pie,
line, bar, etc.) and show the same facts arranged in
multiple ways. The students could use one of the computer
programs to help them produce a graph. Ask the students
to look at the results of two different tests, such
as gloss and hiding, and combine these figures into
a graph. An example is included in the Appendix. In
the viscosity test you ask each group member to run
the test and get a group average. Here you can talk
about averaging and variability (standard deviation,
etc.). Also, the density section (ratios) is another
good one for math.
Social
Studies
With
the introduction of milk paint and whitewash into the
experiments a study of how paint was made and used during
the Colonial Era could be introduced. During Colonial
times special artisans were involved in making and using
paint. Only important buildings received this special
treatment. Whitewash was the common paint used. There
are many versions of whitewash and since milk paint
is also based on lime it makes sense that the simplified
whitewash changed to a more durable milk paint as different
ingredients were added. Challenge the students to begin
with a simple whitewash recipe (see appendix) and add
items that would have been available to the colonists
to make a better paint. Further the study by adding
different natural dyes to create colored paints.
Glossary
Dry
time is the amount of time needed for the paint
to completely dry. Paints dry from the surface down.
Often a paint will appear to be dry, but has skinned
over and is still wet underneath and will be tacky to
the touch. Although the paint does not come off it has
a sticky feel.
Exterior
paint is used outside. It needs to have good
resistance to sun, rain, mildew, and dirt. Exterior
paints often use binders, which have special resistance
to light, heat, and moisture. Because of these special
properties and their high binder content, exterior paints
are often more expensive than interior paints.
Flat
Paint is paint which is not glossy. The lack
of gloss helps mask imperfections in a surface. A dent
in a glossy surface is very easy to see by the change
in the reflections. This is one reason why we often
use flat paints on large wall areas and semigloss or
gloss paints on small areas such as trim.
Flow
is the motion characteristic of liquids moving with
a continual change of place of the constituent particles.
(see Viscosity)
Gloss
is a measure of how shiny a paint is. A glossy paint
is very smooth and light reflects off it as it would
off a piece of clear glass.
Hiding
is the ability of a paint to obscure what is beneath
it. If a paint does not have good hiding, the painters
may need to apply several coats of paint before they
have a uniform color. In most paints, hiding comes from
the white pigment titanium dioxide.
Interior
paint is a paint used inside a building. These
paints do not usually require the weather resistance
of exterior paints, but they often need to have good
stain resistance and scrub resistance.
Latex
is a term derived from the latex which comes from rubber
trees. The sap of the rubber tree is a white, milky
substance which has tiny particles of rubber suspended
in it. When synthetic rubber was discovered, the term
"latex" was kept. We now use "latex"
to describe many suspensions of small rubbery or plastic
particles in water. The latexes used in our paints are
most often based on vinyl or acrylic polymers.
Paint
is a mixture of a pigment suspended in a liquid that
forms a thin adherent coating when spread on a surface.
Paints are used for decoration and/or protection.
pH
is a numerical value used to express acidity or alkalinity,
(acid or base). pH paper or liquid indicators are touched
to the surface of a substance and a color change may
occur. The exact color change is dependent on the indicator.
Some common indicators are red cabbage juice, grape
juice, and phenolphthalein (Ex-Lax).
Scrub
resistance measures how tough a paint is and
how much washing it can withstand.
Stain
resistance measures how easily a material can
stain a paint film and can be removed from the paint.
If the stain penetrates into the paint, it can be very
hard to remove.
Surface
tension is a measure of the inward force on the
surface of a liquid that causes the liquid to form into
drops. Surface tension is due to the tendency of a liquid
to want to remain away from air. The attraction of the
liquid molecules to themselves forces bubble shaped
surfaces which minimize the amount of surface area for
a given volume and minimize the number of liquid molecules
which must contact the air. The surface tension forces
compete with the other phenomena, such as gravitation,
which tend to flatten out the spherical surfaces on
larger length scales. The surface tension is sometimes
thought of as a "skin" on the outer surface
on a bulk liquid.
Substrate
is the base material on which experiments are performed.
Some common examples of a substrate would be cardboard,
wood, glass, plastic, paper, etc.
Viscosity
is the internal resistance to flow exhibited by a fluid.
A liquid with a high viscosity (like maple syrup) flows
slowly.
Weatherability
is the resistance to the damaging effects of weather,
such as sun (light), rain, heat, cold, and dirt.
Bibliography
/ Additional References
Bennet,
H. Everyday Chemistry. "Whitewash Formulae."
The
Chemical Publishing Co.: New York, 1934. p.38.
Gray,
Andrea and Michael J. Gavaghan. "What's (in) the
Solution?"
Projects
Labs 1995. Rohm and Haas. p. 3.8.
Homemade
Milk Paint Recipes. http://www.realmilkpaint.com/recipe.html
Myers,
Tienne Moriniere, Dr. John Hook, Dr. Meredith Morgan.
"Experiments
With
Paints." Project Labs 1991. Rohm and Haas.
p.35.
Appendix
A: Scientific Method
1.
Problem:
This is the question you want to answer. It is helpful
to ask yourself "What do I want to find out?"
Write your problem as a question.
2.
Hypothesis:
This is an educated guess at the answer to the
question. It should be based on what you will do and
what you think you will find out. It should be written
like this: " If I . . (tell what you will do) .
. ., then I think. . .(tell what you think will happen).
. . ."
3.
Procedure: This
is a list of instructions that tells how to do
your experiment. It should be a written as a list 1...
2... 3... 4... etc. It should include enough detail
so that anyone reading it would be able to repeat your
experiment like you did.
4.
Materials:
This is a list of the things you will use to
do your experiment. It should include information about
the sizes and amounts of each item you used. Measurements
must be metric.
5.
Data: As you
do your experiments you should record what happens.
Your data will tell such things as how many, how much
time, or how big. Usually your data will appear in your
project as a bar or line graph. Charts
are also helpful.
6.
Results: This
is a list of what happened in your experiment. Results
tell in sentences what your data tells in a graph or
a chart. Write the order things happened and how much.
7.
Conclusions:
These are final statements that tell whether or not
your hypothesis was true or not true. It can be
begin with one of these two sentences, "The data
supports my hypotheses" or, "The data does
not support my hypothesis." You should write more
sentences to explain how it was or was not supported.
You can also explain why you think what happened in
your experiment occurred.
8.
Application:
This is a short paragraph that tells how people can
use the information you found out in your project.
Write how this information could actually help someone.
Appendix
B: Paint Costs
Paint
- all white Price / Oz Price
per liter
A Washable
Tempera 1.99 / 16 4.22
B Non-washable
Tempera 1.99 / 16 4.22
C Hobby
Acrylic Paint 3.49 / 8 14.79
D Finger
paint 1.79 / 8 7.58
E Oil
Base Primer (Behr) 7.96 / 31.5 8.53
F Oil
Base Exterior Gloss (Duron) 9.95 / 32 10.51
G Oil
Gloss (Rustoleum) 5.92 / 32 6.26
H Latex
Exterior Primer (Behr) 7.83 / 31.5 8.40
I Latex
Hi Gloss Enamel (Behr) 8.94 / 32 9.45
J Latex
Exterior Flat (Behr) 7.94 / 32 8.39
K Latex
Interior Flat (Behr) 7.46 / 32 7.89
L Milk
Paint (Mass. Milk Paint Co.) 10.00 / 6 21.19
Appendix
C: Milk
Paint
Using
Milk Paint as one of the samples will give the students
a unique experience with a paint used during the Colonial
period of our history. It comes in powder form and needs
to be mixed up immediately prior to its use. It cannot
be stored overnight. The paint is made with milk solids
and has a distinct odor, texture, and coat. Because
it so unique it reacts quite differently in many of
the tests. Milk Paint can be obtained at some specialty
hardware stores, or via mail order from The Old Fashioned
Massachusetts Milk Paint Co., Inc., 436 Main Street,
P.O. Box 222, Groton, Massachusetts 01450, 508-448-6336,
fax: 508-448-2754
Appendix
F: Whitewash Recipe
Many
different whitewash recipes are available, containing
a variety of different items. The following recipe contains
basic ingredients. It settles very quickly, and must
be constantly stirred during use. This whitewash dries
to a chalky white/beige color. Some recipes call for
the addition of finely crushed chalk for whiting.
Ingredients:
hydrated lime (see directions below), salt, water
To
hydrate lime, measure out 226 g of lime into a container.
Cover the lime with water, stir, and allow to settle
and rest for five minutes. This is also the method used
to slake lime, a term frequently seen in whitewash recipes.
Pour off excess water.
To
mix whitewash make a saline solution by combining 68
g of salt with 258 g of water. While stirring add the
226 g of hydrated lime.
Appendix
E: Lab Results
Gloss |
3
= letters can be clearly seen - High Gloss |
|
2
= letters can be seen but are clouded or faded
- Semi Gloss |
|
1 = no reflection can be seen - Flat |
A Washable
Tempera 1
B Non-washable
Tempera 1
C Hobby
Acrylic Paint 1
D Finger
paint 1
E Oil
Base Primer (Behr) 1
F Oil
Base Exterior Gloss (Duron) 2
G Oil
Gloss (Rustoleum) 3
H Latex
Exterior Primer (Behr) 1
I Latex
Hi Gloss Enamel (Behr) 2
J Latex
Exterior Flat (Behr) 1
K Latex
Interior Flat (Behr) 1
L Milk
Paint (Mass. Milk Paint Co.) 1
Staining
0
= no staining
1
= light staining
2
= medium staining
3
= severe staining
4 = staining material removed paint coat
Coffee
Red Coloring Ketchup Mustard Jelly
A 4
3 4 4 4
B 3
3 2 4 3
C 3
3 0 2 3
D 4
3 4 4 1
E
1 2 0 2 0
F 1
2 0 2 0
G 0
2 0 2 0
H 2
3 0 2 1
I 0
2 0 2 0
J 2
3 0 2 1
K 3
3 2 2 2
L 3
3 2 3 2
Viscosity
Time
4.5 ml paint needed to flow 10 cm
A Washable
Tempera :15
B Non-washable
Tempera :39
C Hobby
Acrylic Paint :37
D Finger
paint (5 � cm at end of 5 minutes)
E Oil
Base Primer (Behr) :06
F Oil
Base Exterior Gloss (Duron) :19
G Oil
Gloss (Rustoleum) :07
H Latex
Exterior Primer (Behr) :08
I Latex
Hi Gloss Enamel (Behr) :10
J Latex
Exterior Flat (Behr) :14
K Latex
Interior Flat (Behr) :20
L Milk
Paint (Mass. Milk Paint Co.) (7 cm at end of 5 minutes)
Surface
Tension
3
= a dome appearance
2
= a semi-flat appearance
1
= a flat appearance
0
= can't form a drop.
15
Minutes 3 Hours
A Washable
Tempera 2 1
B Non-washable
Tempera 3 2
C Hobby
Acrylic Paint 2 1
D Finger
paint 3 3
E Oil
Base Primer (Behr) 1 1
F Oil
Base Exterior Gloss (Duron) 2 2
G Oil
Gloss (Rustoleum) 1 1
H Latex
Exterior Primer (Behr) 2 1
I Latex
Hi Gloss Enamel (Behr) 2 1
J Latex
Exterior Flat (Behr) 2 1
K Latex
Interior Flat (Behr) 2 1
L Milk
Paint (Mass. Milk Paint Co.) 3 3
Acid/Base
p
= purple Starch p = purple/black
r
= red br = brown
b
= blue/green
pH Starch
A Washable
Tempera b p
B Non-washable
Tempera b p
C Hobby
Acrylic Paint b br
D Finger
paint b p
E Oil
Base Primer (Behr) p br
F Oil
Base Exterior Gloss (Duron) p br
G Oil
Gloss (Rustoleum) p br
H Latex
Exterior Primer (Behr) p br
I Latex
Hi Gloss Enamel (Behr) p br
J Latex
Exterior Flat (Behr) p br
K Latex
Interior Flat (Behr) b br
L Milk
Paint (Mass. Milk Paint Co.) b br
Dry
Time /minutes
W
= wet - wet paint sticks to glove
T
= tacky - paint does not stick to glove but is sticky
to touch
D
= dry - paint has completely dried, is not sticky at
all
10
15 20 25 30 35 40 45 50 55 60 Dry in:
Sample
A W W W D 25 m
Sample
B W D 15 m
Sample
C D 10 m
Sample
D W W W D 25 m
Sample
E W W W W W W W T T T T
Sample
F W W W W W W W W W W W
Sample
G W W W W W W W W W W W
Sample
H W W W T T T T T D 50 m
Sample
I D 10 m
Sample
J D 10 m
Sample
K D 10 m
Sample
L W W T T T D 35 m
Metal
Marking
0
= no visible marks
1
= light metal marks
2
= medium metal marks
3
= dark metal marks
Metal
Mark
A Washable
Tempera 2
B Non-washable
Tempera 2
C Hobby
Acrylic Paint 3
D Finger
paint 1
E Oil
Base Primer (Behr) 1
F Oil
Base Exterior Gloss (Duron) 1
G Oil
Gloss (Rustoleum) 1
H Latex
Exterior Primer (Behr) 1
I Latex
Hi Gloss Enamel (Behr) 1
J Latex
Exterior Flat (Behr) 3
K Latex
Interior Flat (Behr) 3
L Milk
Paint (Mass. Milk Paint Co.) 1
Density
Weight(g)
Volume(ml) Density(g/ml)
Base Water 15.8
15.8 1.00
A Washable
Tempera 19.7 15.8 1.24
B Non-washable
Tempera 22.1 15.8 1.39
C Hobby
Acrylic Paint 25.1 15.8 1.58
D Finger
paint 18.5 15.8 1.17
E Oil
Base Primer (Behr) 22.9 15.8 1.44
F Oil
Base Exterior Gloss (Duron) 20.5 15.8 1.29
G Oil
Gloss (Rustoleum) 18.0 15.8 1.13
H Latex
Exterior Primer (Behr) 20.9 15.8 1.32
I Latex
Hi Gloss Enamel (Behr) 20.8 15.8 1.31
J Latex
Exterior Flat (Behr) 23.3 15.8 1.47
K Latex
Interior Flat (Behr) 22.9 15.8 1.44
L Milk
Paint (Mass. Milk Paint Co.) 17.3 15.8 1.09
Hiding
4
= Letters cannot be seen at all
3
= Shadows seen, individual letters not recognizable
2 = Letters can be seen under the paint, most
words can be read
1
= Letters/words can be easily read
0
= Paint sample does not adhere to cereal box
A Washable
Tempera 1
B Non-washable
Tempera 2
C Hobby
Acrylic Paint 4
D Finger
paint 1
E Oil
Base Primer (Behr) 2
F Oil
Base Exterior Gloss (Duron) 3
G Oil
Gloss (Rustoleum) 3
H Latex
Exterior Primer (Behr) 0
I Latex
Hi Gloss Enamel (Behr) 2
J Latex
Exterior Flat (Behr) 3
K Latex
Interior Flat (Behr) 3
L Milk
Paint (Mass. Milk Paint Co.) 4
Scrubability
#
of strokes to totally remove paint from the surface
100
+ = paint not removed from surface after 100 strokes
md
= after 100 strokes there was medium damage
ld =
after 100 strokes there was light damage
409 Ajax Dawn Fantastic
A Washable
Tempera 3 2 2 4
B Non-washable
Tempera 10 4 6 12
C Hobby
Acrylic Paint 90 50 100+ 30
D Finger
paint 10 15 15 5
E Oil
Base Primer (Behr) 100+ 100md 100+
100+
F Oil
Base Exterior Gloss (Duron) 100+ 100md 100+ 100+
G Oil
Gloss (Rustoleum) 100+ 100ld 100+ 100+
H Latex
Exterior Primer (Behr) 100ld 80 100+ 74
I Latex
Hi Gloss Enamel (Behr) 100+ 100+ 100+ 100md
J Latex
Exterior Flat (Behr) 60 100+ 100+ 70
K Latex
Interior Flat (Behr) 25 100md 100+ 30
L Milk
Paint (Mass. Milk Paint Co.) 100+ 100+ 100+ 100+
This experiment is courtesy of 
|
|
|