Glue From Milk
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Third grade students in the Mifflin County School
District attended science class outside their normal
classroom setting this week. The PA Farm Bureau's Mobile
Ag Ed Science Lab was on site at Highland Park Area
Elementary School and open for instruction.
The students traveled to HPAE for their science lab
on "Glue From Milk". While at the lab, the
students were provided with instructions and materials
in order to act as chemists and laboratory technicians
as they producee glue from milk. All labs were
instructed by a certified teacher from outside the MCSD.
During lab instruction, students learned first hand how
common household materials such as vinegar, milk and
baking soda interact with each other when combined in
the correct order and proportions. They also became
aware that a scientist mixes and separates ingredients
differently than we do at home.
The problem the students were trying to solve
was: Which was stronger? (Milk glue or a commercial glue
such as Elmer's)
 They
were also asked to write a hypothesis and why.
Following a discussion of what a hypothesis was, the
instructor explained that there were no wrong answers.
Many in the class thought the milk glue would be
stronger, because it looked thick, or smelled strong.
The teacher explained that viscosity test is one
way to predict a possible result. She demonstrated the
viscosity of milk glue vs. Elmer's glue by placing a
small amount of each on a paper plate to see which was
slower. The milk glue started out as a thinner product,
but quickly slowed and the commercial glue caught up and
they ended up in a tie.
 Before
leaving the lab, student prepared control samples to
take back to their classroom so they could compare their
original hypothesis with their conclusion. They tested
for P - peel strength, S - sheer strength
and T - tensile strength. Each student prepared
either samples of milk glue or Elmer's glue with
construction paper, labeling each so they could keep
track of their findings when the glue dried, creating a
strong bond.
To follow along with the 3rd grade scientists, please
see the images below. If you would like to see a larger
image, click on the small picture, then use the back
button on your browser to return to this page. Which
do you think is stronger? Milk glue or commercial glue?
If you know a 3rd grade student in the MCSD, ask
about their conclusion!
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