journal
of science education
Classroom
In this section of Resonance, we invite readers to pose
questions likely to be raised in a classroom situation. We may suggest
strategies for dealing with them, or invite responses, or both. “Classroom”
is equally a forum for raising broader issues and sharing personal experiences
and viewpoints on matters related to teaching and learning science.
How much Flour should you Pack
in a 1 kg Packet
Use of a Gaussian Model
``What a silly question! Obviously the answer is 1 kg!!'' If you say that, then on the classroom1, you should have asked how we can book more than 200 seats in a 200-capacity flight. But you let us ask that question and even let us get away with answering the question. The answer to the question asked here is similar in spirit to the answer to the flight overbooking problem, but the details are different.
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Project Lifescape –
11
Hunter Plants
Hunter plants are among the curiosities of nature, being
very different from normal plants in their mode of nutrition. They, however,
never prey upon humans or large animals as often dep-icted in fiction
or fables. They are specialised in trapping insects and are popularly
known as insectivorous plants. Way back in 1875, Charles Darwin drew the
attention of the scientific com-munity to the world of insect eating plants
in one of his essays.
Classroom Experiment to
verify
the Lorentz Force
The Lorentz force is a phenomenon of fundamenta importance
in electricity and magnetism for it gives a law for the interaction between
a magnetic field and a current i.e. a charge in motion. This interaction
between a magnetic field and a moving charge, first discovered by Faraday,
and expressed mathematically as the Lorentz force is the basis of many
devices (the most popular being an electric motor). It also provides explanation
of many electromagnetic phenomena. Yet, as far as we are aware, very little
is done in undergraduate laboratories to demonstrate this force in a quantitative
or semi-quantitative way.
Brownian Motion: Theory
and Experiment
A Simple Classroom Measurement of the
Diffusion Coefficient
Brownian motion is the perpetual irregular motion exhibited
by small particles immersed in a fluid. Such random motion of the particles
is produced by statistical fluctuations in the collisions they suffer
with the molecules of the surrounding fluid. Brownian motion of particles
in a fluid (like milk particles in water) can be observed under a microscope.
Here we describe a simple experimental set-up to observe Brownian motion
and a method of determining the diffusion coefficient of the Brownian
particles, based on a theory due to Smoluchowski. While looking through
the microscope we focus attention on a fixed small volume, and record
the number of particles that are trapped in that volume, at regular intervals
of time. This gives us a time-series data, which is enough to determine
the diffusion coefficient of the particles to a good degree of accuracy.
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