El capital social y la identidad empresarial

II. CONTENT Module IV: LIGHT

Lesson 20: REFRACTION OF LIGHT RAYS

III. LEARNING RESOURCES

A. References

1. Teacher's Guide Pages 55-56

2. Learner's Materials Pages 94-97

3. Textbook Pages

4. Additional Materials from Learning

Resource (LR) portal

B. Other Learning Resource

IV. PROCEDURES

A. Reviewing previous lesson or presenting the

new lesson How do sound waves reflect and refract?

B. Establishing a purpose for the Lesson

Light exhibits the characteristics and properties of a wave. Light tends to travel in a straight line, unless it is acted on by some external force or condition. "What kinds of forces or conditions can affect light, and how?" To answer this question, we start with what we can see in everyday life.

from each other.

C. Presenting examples / instances of the new lesson

Why do our finger look swollen or big when we dip it into the water? Ask the students if they know the meaning of work.

Emphasize to them that the meaning /definition of work and the one that we use in Science are quite different.

D. Discussing new concepts and practicing new skills #1

Activity-See Lesson Guide pp 77-78

E.

Discussing new concepts and practicing new skills #2

6. How would this indices of refraction account for the arrangement of colors of light?

F.

Developing mastery

(Leads to Formative Assessment 3)

Discuss the answers in the activity given

G

Finding practical applications of concepts and skills in daily living

When driving on a black road on a hot day, you may see what appear to be a puddle of water up ahead of you. But when you get there, it is dry. Why?

What is this phenomenon called? (a mirage)

H.

Making generalizations and abstractions about the lesson

Light travels in a straight line. This is so as long as long as the medium in which it is traveling is uniform all throughout.

When light crosses a boundary between two transparent media of different optical densities, light bends. The bending of light due to change in its speed is called refraction. When light travels from air to water, the speed of light decreases because the optical density of water is greater than air.

Light travels in

a straight line. This is so as long as long as the medium in which it is traveling is uniform all throughout. When light crosses a boundary between two transparent media of different optical densities, light bends. The bending of light due to change in its speed is called refraction. When light travels from air to water, the speed of light decreases because the optical density of water is greater than air.

In figure 3, θi is the angle of incidence and θr is the angle of refraction (the angle between the outgoing ray, in the medium, and the normal to the boundary).

As light enters an optically more dense material, the angle of refraction is smaller than the angle of incidence-the light bends toward the normal. Likewise, if light passes from an optically dense medium to a less dense medium, the light bends away from the normal.

A known indicator of the optical density of a material is the index of refraction of the material. Index of refraction represented by the symbol n is the ratio of the speed of light in vacuum and its speed in another medium. In symbols;

n= speed of light in a vacuum speed of light in material

The ratio is always greater than 1. For water, n is usually equal to 1.360 while air is more or less comparable to vacuum so its n is 1.000.

In figure 3, θi is the angle of incidence and θr is the able of refraction (the angle between the outgoing ray, in the medium, and the normal to the boundary).

As light enters an optically more dense material, the angle of refraction is smaller than the angle of incidence-the light bends toward the normal. Likewise, if light passes from an optically dense medium to a less dense medium, the light bends away from the normal.

A known indicator of the optical density of a material is the index of refraction of the material. Index of refraction represented by the symbol n is the ratio of the speed of light in vacuum and its speed in another medium. In symbols;

n= speed of light in a vacuum speed of light in material

The ratio is always greater than 1. For water, n is usually equal to 1.360 while air is more or less comparable to vacuum so its n is 1.000.

I. Evaluating Learning

Direction: Complete each statement by supplying the correct term. You may choose the answer from the box below.

Refraction bends towards the normal Mirage incident ray

bends away from the normal medium

1. The bending of light when it passes obliquely from one medium to another is known as ________. (refraction)

2. Refraction is the bending of light from one ________ to another. (medium)

3. When light passes from a less dense to a denser medium, it _____.

(bends towards the normal)

4. When a light ray passes from water to air (denser to a less dense medium), its path __________. (bends away from the normal)

5. The phenomenon that motorists observe on hot days when the road seems to be covered with water. (mirage)

J. Additional activities for application or

remediation

What are the different colors of light?

V. REMARKS

VI. REFLECTION

A. No. of learners who earned 80% in the evaluation

B. No. of learners who require additional activities

for remediation who scored below 80%

C. Did the remedial lessons work? No. of learners who have caught up with the lesson

D. No. of learners who continue to require

remediation

E. Which of my teaching strategies worked well?

Why did these worked?

F. What difficulties did I encounter which my

principal or supervisor can help me solve?

G. What innovation or localized materials did I

Use or discover which I wish to share with other teachers?

GRADES 1 to 12 School Grade Level Grade 8

Daily Lesson Log Teacher Learning Area Science

Teaching Date and

Time Quarter First (Physics)

DAY:

I. OBJECTIVES

A. Content Standards The learner demonstrates understanding of some properties and