1. An effective approach to online physics
by incorporating home based
experiments
Wednesday, May 11th, 2005
Hamilton Club
Presented by:
Prof. Mike Mikhaiel
Science Department
2. INTRODUCTION
In the area of education, online
environments of learning now exist and are
increasing at an exciting rate. Such
environment offer great potential and huge
possibilities of education especially in the
United States and the Western world.
3. Online learning is used to deliver courses of
various disciplines. However, their potential
may only be realized if teachers can
accommodate their personal theories, beliefs,
and practices to suit the characteristics of the
new environment.
4. Online learning is not just a matter of
gathering notes and presenting it online but
instead, new ways have to be defined, to
evolve and adapt to the new environment.
5. The task of offering science subjects online
is very difficult to deliver especially when
experiments are a crucial part of the
evaluation process. Interactive virtual
activity and simulations have been
developed and used to replace them and
some educators have endorsed this method
while others have not.
6. QUESTION
The question remains: are virtual
experiments comparable with traditional
experiments?
ANSWER
The answer to this question is yes.
7. SOLUTION
• I devised a method where students can
actually perform experiments similar to
what they would do in traditional methods.
• The experiments may be different but the
concepts, procedures, and the end results
are the same.
8. NEW EXPERIMENTS
The new experiments are experiments that
can be done at home or everywhere using
materials found everyday in a dollar store
and in most cases at home.
9. EXPERIMENT 1
Measuring the speed of light with chocolate
and a microwave.
• Equipments: A microwave, a ruler and chocolate, cheese or any other food
that melts.
• Procedure:
1. Remove the turntable from the microwave and replace with chocolate on the
surface.
2. Heat until the chocolate just starts to melt.
3. There will be some melted hot spots and some cold solid spots in the
chocolate.
• Measurements: measure the distance between the hot spots.
• Analyze: The distance between the hot spots is half the wavelength of the
microwave.
• Calculations: Now you are ready to find the speed of light.
Find the frequency of the microwave by reading the printed frequency on the
back of the microwave.
The speed of light is equal to the wavelength multiplied by the frequency of
the microwave.
10. EXPERIMENT 1 EXPLANATION
When you turn on your microwave oven, electrical
circuits inside start generating microwaves-
electromagnetic waves with frequencies around
2.5 gigahertz-2500000000 Hz. These waves
bounce back and forth between the walls of the
oven, the size of which is chosen so that the peaks
and troughs of the reflected waves line up with the
incoming waves and form a “standing wave”.
11. EXPERIMENT 1 EXPLANATION (CONT.)
• The wave forming inside the microwave is a
standing wave with half the wavelength. This
wave has nodes and antinodes. Nodes will give
you minimum vibrations and you see part of the
chocolate is cold and antinodes will give you
maximum vibrations and you see the chocolate is
melting in this area.
• you will find the speed of light (C) by using the
equation C = λƒ.
12. EXPERIMENT 2
How to tell a diamond from a cubic zirconia
Background information: The cubic zirconia is a
reasonably good “fake” diamond- although calling it a fake
diamond is perhaps a little unfair- the cubic zirconia is a
gemstone in it own right, referring to it as a fake diamond
makes it sound like the glass “stones” used in costume
jewelry. The reason that it is possible for a cubic zirconia
to pass as diamond to casual or untrained scrutiny is that
the cubic has many of the properties of a diamond-they are
the same shape and color. However, there is one important
property of diamonds that a cubic cannot mimic well- the
“sparkle.”
13. Theory: Diamonds have a very high refractive index- this
means that light entering or leaving a diamond will be bent
strongly as it crosses the diamond-air interface. The
amount of bending is given by Snell’s Law:
Sin θ1/Sin θ2 = n1/n2
Thus, we can see that when light travels from diamond (n
for diamond is 2.42) to air (n for air is 1) the sine of the
angle made by the beam of light in the air is greater than
the angle made in the diamond.
14. • Further, you can see that the, above some critical angle of
incidence, the “sin(theta in air)” given by Snell’s Law will
be greater than 1.
• As this is impossible, we know that above the critical
angle, we cannot have refraction. But the light has to go
somewhere- it is reflected back into the diamond.
• In a cubic zirconia, the refractive index is smaller (n for
zirconia is 2.14) so the critical angle in the cubic is greater.
15. Experiment: We see the clear gemstones in the air because
of the light that reflects off their faces. The amount of
reflection is related to the difference in refractive index
between the gemstone and air. In this situation, the cubic
and the diamond reflect a very similar amount of light.
But, if you submerge the gemstones in water, the ratio of
the refractive index differences increases markedly.
Thus, if you submerge a cubic zirconia in a glass of water,
the gemstone virtually disappears, while a diamond is still
easily visible.
