from the center, explaining their
predictions with phrases like, “the
more distance between the center of
the galaxy and the stars, the less pull
gravity has, so stars will orbit slower.”
They were amazed when I shared the
actual data, which shows that orbital
velocities increase and level out with
distance. I also pointed out that stars
orbiting at that velocity should be
flying out of their orbits—yet they
As they discussed this data, student
groups lit up with explanations. My
questioning guided students back to
their understanding of gravity, mass,
and proximity, and their effects on
orbital speeds. Eventually, each group
decided there must be some sort of
“missing mass” within the galaxies
that holds them together and causes
the orbital velocities of the outermost
stars to remain high—but that this
mass wasn’t showing up on the
electromagnetic spectrum. This led
students to request additional infor-
mation about the existence of dark
matter and how it can be detected.
For instance, one student revised her
explanation like this:
We decided there has to be more gravity
to hold onto [the stars]. But we didn’t
know where it was coming from because
we can’t see anything else. A group
member said it’s dark matter, but we
don’t have any evidence (yet!) that it is.
Strategic discourse and predictive
questioning are integral to learning
through inquiry in science classrooms.
Used together, these tools tease out
students’ misconceptions, create
opportunities for meaningful dialogue
among students, facilitate higher levels
of student engagement, and result in
deeper learning. EL
Abell, S. K., & Lederman, N. G. (Eds.).
(2010). Handbook of research on science
education. New York: Routledge.
Chin, C. (2007). Teacher questioning in
science classrooms: Approaches that
stimulate productive thinking. Journal
of Research in Science Teaching, 44( 6),
Di Teodoro, S., Donders, S., Kemp-Davidson, J., Robertson, P., & Schuyler,
L. (2011). Asking good questions: Promoting greater understanding of mathematics through purposeful teacher and
student questioning. Canadian Journal of
Action Research, 12( 2), 18–29.
Fisher, D., & Frey, N. (2010). Guided
instruction: How to develop confident
and successful learners. Alexandria, VA:
White, R., & Gunstone, R. (1992). Probing
understanding. New York: Routledge.
Jaunine Fouché ( firstname.lastname@example.org)
is preK– 12 science curriculum supervisor
at the Milton Hershey School in Hershey,
Students can’t look up the correct answer if you
ask a question that has no correct answer.
I do this all the time by asking Fermi-type
questions in class. A Fermi question is
a question that, at first glance, seems
impossible to answer. The students must
use educated guesses and estimation skills
to submit their best answer based on sound
reasoning. It is important that the students show
all of their work.
For example, at the end of a measurement unit
in science class, I show the students a picture of a
cement truck and a pair of dice, and ask them, “What
is the weight of the cement truck measured in board
game dice?” I ask my chemistry classes, “How many
water molecules can you fit in your mouth?” and ask
the students to submit a plan to actually test
their answer. It is shocking how thorough
they can be. Ask any math class, how
many dollar bills are required to cover the
surface area of the Atlantic Ocean. Show
the students a world map and ask them to
do it without a calculator.
My personal favorite for a Friday
afternoon, great for many different classes, is
“How many times can I listen to the song, ‘I’m Gonna
Be (500 Miles),’ while actually walking 500 miles?” Play
the song in the background to make things interesting.
—Ben Arcuri, chemistry teacher,
Penticton Secondary School, Penticton, British Columbia
For more great questions suggested by our readers, see our
“Tell Me About” column on p. 90.
NOW THAT’S A GOOD QUESTION!
How Many Water Molecules Fit in Your Mouth?
MR. HIGH SKY/SHUT TERSTOCK