DETAILED LESSON PLAN
I. OBJECTIVE
At the end of 30 minutes, the students should be able to:
1.
State and explain Huygens Principle.
II. SUBJECT MATTER (LEARNING TASK)
1.
Topic: Physical Optics: The Wave Nature of light.
2.
Reference: Encyclopedia Britanica, ScienceDirect Topics.
3.
Materials: Laptop, Visual aids and Mobile Phone.
III. PROCEDURE (DEVELOPMENTAL ACTIVITY)
Teacher’s Activity
1.
Pre Activity
1.
Preparation
Student’s Activity
(Amen!)
Let’s stand up and let us pray!
Good morning ma’am!
Good morning class!
May you now take your seat.
Please say present when I call your name.
2.
Review
(The students will say present when their
name is called)
What is our last topic yesterday?
(The student will answer: our last topic is
all about Diffraction and Polarization)
But before we start to our new lesson lets
freshen up first by recalling our last topic.
Okay, so what is Diffraction and
Polarization?
(The student will answer: Diffraction and
Polarization are the bending of waves
around obstacles, corners, or openings.)
3.
Motivation
Now, I have here three (3) images at the
screen. What are you going to do is to simply
identify each image and explain why?
PICTURE 1
PICTURE 2
PICTURE 3
So, for picture number one (1), as I call your
name please stand up and identify the
picture and the same for picture number two
(2) and three (3).
Ok, very good! Since I’ve discussed
yesterday the things about diffraction and
polarization.
Now, we will be discussing about Physical
Optics: The Wave Nature of light especially
the Huygens Principle.
4.
Unlocking of Terms
But before we go deeper to our main goal this (Three students will stand up and
day, let’s define first these terms:
identify the pictures.)
Huygens Principle- states that every point
on a wave front may be considered as a
source of secondary waves.
Wave front- is an imaginary surface
representing corresponding point of a wave
that vibrate in unison.
Diffraction- is the spreading of waves from
as they pass through or around obstacle.
Refraction- is the bending of light as it
passes from one transparent substance into
another
5.
Activity Proper
So, do you want some fun?
But before that I will give you some
important information about Huygens
Principle, especially the person behind this
principle Christian Huygens.
So, Christiaan Huygens, also spelled
Christian Huygens, (born April 14, 1629, The
Hague- died July 8, 1695, The Hague). Dutch
mathematician, astronomer, and physicist,
who founded the wave theory, discovered the
true shape of the rings of the Saturn, and
made an original contribution to the science
of dynamics- the study of the action of forces
of bodies.
So, lets go back to the principle called
Huygens Principle.
Huygens Principle, also called Huygens
Fresnel Principle, a statement that all points
of a wave front of sound in a transmitting
medium of light in a vacuum or transparent
medium may be regarded a new source of
wavelets that expand in every direction at a
rate depending on their velocity.
(Students will read in the definition of
terms together.)
Huygens Principle and Diffraction
When light passes through an aperture,
every point on the light wave within the
aperture can be viewed as a source creating
a circular wave that propagates outward
from the aperture. The aperture thus creates
a new wave source that propagates in the
form of a circular wave front. The center of
the wave front has greater intensity while the
edges have a lesser intensity. This explains
the observed diffraction pattern and why a
perfect image of the aperture on a screen is
not created. A daily life example of this
phenomenon is common. If someone in
another room calls toward you, the sound
seems to be coming from the doorway.
Advantages and Disadvantages of Huygens
Principle
Advantages:
1.
Huygens concept proved the reflection
and refraction of light.
2.
The concepts like diffraction of light,
as well as interference of light, were
proved by Huygens.
Disadvantage:
1.
Concepts like emission of light,
absorption of light and polarization of
light were not explained by Huygens
principle.
2.
Huygens principle failed to explain the
photoelectric effect.
3.
A serious drawback is that the theory
proposes an all-pervading medium
required to propagate light called
luminiferous ether. This was proved to
be false in the 20th century.
Okay, now let’s have some fun!
This is an individual activity.
Instruction:
I have here a picture and what are you
going to do, is to name every part of the
diagram.
C. Post Activity
1.
Analysis
I am glad that you’ll already know how to
identify each part of the diagram as an
example of diffraction that we tackled earlier!
I hope you all enjoy having this kind of
activity as part of our lesson for this day.
Okay, so everyone, please pass your paper in
front for I will check it who got the perfect
score!
Anyone? who can go to front and name each
part of the diagram.
Okay! Very good!
2.
Abstraction
So, Huygens Principle is also called as
what?
What the advantages of Huygens
Principle?
What are the disadvantages of
Huygens principle?
3.
Application
Why it is really important to study
Huygens principle and its importance
to our daily lives?
Now, what are the contributions of
Huygens principle to us?
Ok, very good!
So, did you know how to identify the parts of
diffraction?
Are you sure?
Any questions or clarification?
(The students will stand up and pass
their works to me.)
(one student will go to the front and
name each part.)
(The students will answer: it is also called
as Huygens Fresnel Principle.)
(The student will enumerate the two (2)
advantages of the principle.)
(The students will enumerate the three
(3) disadvantages of the principle.)
(One student will stand up and answer
the question according to his/her
understanding.)
(One student will stand up and answer
the question according to his/her
understanding.)
(Yes sir!)
(Yes sir!)
(No sir!)
IV. EVALUATION
Get 1 whole sheet of yellow pad paper and answer the following questions!
TEST I: MULTIPLE CHOICE
1.
What is Huygens Principle?
1.
an imaginary surface representing corresponding point of a wave
that vibrate in unison.
2.
states that every point on a wave front may be considered as a
source of secondary waves.
2.
3.
4.
5.
3.
the spreading of waves from as they pass through or around
obstacle.
4.
the bending of light as it passes from one transparent substance
into another.
What is a wave front?
1.
the bending of light as it passes from one transparent substance
into another.
2.
states that every point on a wave front may be considered as a
source of secondary waves.
3.
an imaginary surface representing corresponding point of a wave
that vibrate in unison.
4.
the bending of light as it passes from one transparent substance
into another.
What is Diffraction?
1.
the bending of light as it passes from one transparent substance
into another
2.
states that every point on a wave front may be considered as a
source of secondary waves.
3.
an imaginary surface representing corresponding point of a wave
that vibrate in unison.
4.
the spreading of waves from as they pass through or around
obstacle.
Which is best describe as an advantage of Huygens principle?
1.
Concepts like emission of light, absorption of light and
polarization of light were not explained by Huygens principle.
2.
Huygens principle failed to explain the photoelectric effect.
3.
A serious drawback is that the theory proposes an all-pervading
medium required to propagate light called luminiferous ether. This
was proved to be false in the 20th century.
4.
Huygens concept proved the reflection and refraction of light.
Huygens Principle also called as?
1.
Huygens Fresnel Principle
2.
Huygens freshnel Principle
3.
The Principle of Huygens
4.
Fresnel Huygens Principle
TEST II: Explanation
1.
Why is Huygens Principle is correct?
2.
How is Huygens Principle is derived?
3.
What are the main drawbacks of Huygens Principle?
V. ASSIGNMENT
Why is Huygens Principle is important? elaborate your answer.
VI. Remarks
M.L. :
I. D. :
Prepared by: JESTER L. OLAM