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RANDY BELL’S “CANDLE” OBSERVATIONS, INFERENCES AND NOS
Presenter: Katey Shirey, Washington-Lee High School, katherineshirey@gmail.com
Va. SOL:
PH.3 The student will investigate and understand how to demonstrate scientific reasoning and
logic. Key concepts include:
c) evaluation of evidence for scientific theories;
d) examination of how new discoveries result in modification of existing theories or
establishment of new paradigms; and
e) construction and defense of a scientific viewpoint (the nature of science).
National Standards:
Science as Inquiry Standard. p. 105
In the vision presented by the Standards, inquiry is a step beyond ''science as a
process," in which students learn skills, such as observation, inference, and
experimentation.
Topic/Concept
In this demo the teacher uses a seemingly innocent “candle” to practice observation and
inference, then delivers a discrepant event to cause students to re-examine their
theories about the situation. This demo also is a great example for the Nature of
Science, that here are more than one possible explanation for observations, science in
tentative and theories can change as new evidence is gathered.
Materials
string cheese
almond sliver
skinny coffee stirrer type straw
lighter
Safety Considerations
You could burn yourself with fire slightly, but no worse than a piping hot pizza could.
Presentation
Set up the candle before hand. To set up, insert straw/stirrer into the “candle” the long
way to reduce it’s jiggling. Put one almond sliver in one end to resemble a wick. You might
want to model each of these additionally with an exacto knife for realism. Burn the almond
sliver and blow it out so it looks like it has burned before, and so that it lights easier the second
time.
“Candle” Observation, Inference and NOS 1
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In front of the class, dim the lights (or not) and tell the students you’d like them to make
observations about a very special piece of equipment. Present the “candle” but don’t call it by
name. Have students observe on paper or out loud. Light the candle and ask them to
continue observing. After about 20 seconds it might start to sputter so you’ll have to cut the
observing short.
Tell them that you’re going to do something and they should continue taking
observations. Bite the top off the candle, lit almond and all, chew and swallow. Ask them to
continue making observations.
Discussion, were some of their observations really inferences? Were any of them not
surprised?
Nut Sliver
String Cheese
How the physics is demonstrated
This is a NOS activity. It does give an opportunity to observe and infer, but it mostly is
about assumptions and how dangerous they are in science. It is also about how new
evidence changes our current understandings.
Sources & References
Please see Teaching the Nature of Science Through Process Skills: Activities for
Grades 3-8 By Randy L. Bell ISBN-13: 9780205433339
“Candle” Observation, Inference and NOS 2