Grow Bacteria, Grow!
MS 282 Park
Slope Middle School, Brooklyn
Program for Science Teachers
6 - 8
Diversity of Life
1 - 50 minute class, 10 minutes at
the beginning of each class for 4 days
Students will measure and
observe the growth of bacteria colonies in two different temperatures.
Students will be able to:
Identify bacterial colonies on Petri
Graph bacterial growth through
Predict the continued growth
of bacterial colonies given different parameters
Observation, inferences, hypothesis
agrose in petri dishes 1 per student
Flat toothpicks (with
dull end so agrose is not punctured) or Q-tips
Bleach cleaning spray and paper towels for thorough clean-up
Parafilm (or as an alternative clear tape)
Refrigerator (or two locations with >20 degree C
By growing bacterial colonies in two
different temperature environments, students will see the effect of temperature
on growth, and can begin to form their own ideas about what environments may or
may not aid bacterial growth.
- Divide students
into pairs; each pair receives 2 petri dishes with bacterial agrose.
students decide one 1 location in the school/classroom to “swab” for
bacteria onto both dishes.
a clean Petri dish
with agrose so students have a basis for comparison.
soft “S” shaped
motions, students drag their swab onto both Petri dishes. Make sure students
have taken 4 or 5 swabs from their location.
the Petri dishes, and
seal the edges with parafilm or clear tape.
label the petri dish
with the students initials, date and swab location (eg “doorknob”). Make
sure to label along the edge of the petri dish and not the center, so the
colonies can be clearly counted and are not obscured by the writing.
pictures of the petri
dishes or have students make drawings in their science notebooks of their
bacterial colonies (Day 1 will have no growth).
one of the petri
dishes in a warm location (windowsill) and the other in a refrigerator, or
in an area that stays relatively cool.
the first 10 minutes
of class for the next 4 days for observation.
graph results on a
two-coordinate line graph, where “day” is on the x axis and “number of
colonies” is the category on the y axis.
What do you think would have happened to
the colonies if you left them to grow for another week?
other variables might
you test to aid or inhibit the growth of bacterial colonies?
did the growth of the
bacterial colonies in the two different temperature environments compare?
New York City Science Standards:
Living Environment 1.1a-c