Science 4 Quarter 3

2. OBJECTIVES:
1. Describe how light travels.
2. Infer that light travels in a straight
line; and
3. Show through various activities that
light travels in a straight line.

3. How
does
light
travel?

16. Activity No. 1
Direction: Give at least four things that give light in your house
during day time and during night time.

17. Activity No. 2: EXPERIMENT
Materials:
 Flashlight or Laser
 3 pieces of illustration board (used board will do
Note: 1/16 size with 2” diameter hole in the mid
 1-piece thick cardboard
 Observation sheet

18. General Instructions and Rules in Practic
Safe Science at Home:
1. Have the materials on hand.
2. Read the procedures ahead.
3. Follow the directions carefully.
4. Be careful in doing experiments.
5. If at first you don’t succeed, try and try
again.
6. Record your experiment.

19. Activity No. 2: EXPERIMENT
What to do:
1. Get a flash light and aim it at a distance
wall or at the ceiling. Observe the path of
light.
2. Ask your groupmate to block the path
coming from the flashlight with a thick
cardboard. Observe what will happen.

20. What to do:
3. Get three illustration boards with 2”
diameter hole in the middle. Arrange the
illustration boards next from one another.
Make sure that the holes are aligned in
such a way that the wall could be seen
through the holes.
4. Aim the flashlight/laser through the first
hole. Observe what happens.
5. Misalign the 2nd illustration board. Keep
the light aimed at the illustration boards.
Observe what will happen.

21. 1. Did the light form a straight line when
you aimed it on the wall or ceiling without
blockage?
2. When you blocked the light with a thick
cardboard, was it able to pass through it?
Explain your answer.
3. When you aligned the cardboards with
holes, was the light able to pass through it?
GUIDE QUESTIONS:

22. 4. When one of the cardboards was not
aligned with the other cardboards, was the
light able to pass through the other
cardboards? Why is this so?
5. What can you say about the way light
travels?
GUIDE QUESTIONS:

23. LIGHT is electromagnetic radiation that
can be detected by our eyes.
It always travels in a straight line when
passing through a single medium or any
substance through which a light wave can
pass and travel.
 Light does not need air or any media to
travel. The light from the sun can travel
in space or vacuum and reaches the
Earth.
WHAT IS IT?

24. Light can travel even without a medium. It
travels very fast.
Mediums like air, water and glass allow light to
pass through. These are called transparent
materials.
While materials like a cardboard, a book, a
wood or a plastic chair or a wall can block the
light. These are called opaque materials.
WHAT IS IT?

25. The nature of light made investors
harness it to be used in various
technologies like laser and optical
fibers.
• A laser is a narrow but
powerful beam of light. It can travel
long distances and still focus on small
are. We use laser light when we store
information on a CD. It is also used to
read bar codes in stores, libraries and
other establishments. It is used in
WHAT IS IT?

26. WHAT IS IT?
• In medicine, doctors use
laser to treat certain
problems with organs, the
eye and the skin.

27. • Optical fibers on the
other hand are very thin glass
or plastic fibers that are
bundled together in a coated,
flexible tube. The tube can be
twisted or bent without
affecting the image that is
sent.
WHAT IS IT?

28. WHAT IS IT? • Optical fibers are made
from transparent materials that
transmit visible , ultraviolet and
infrared light. The information
they carry quickly travels long
distances. Optical fibers are
used in communication,
medicine and industry.

29. Remember these:
• LIGHT- a form of energy that gives
by the sun (natural light) and other
light sources (artificial light).
• LIGHT ALWAYS TRAVEL IN A
STRAIGHT LINE.
GENERALIZATION:

30. Directions: Fill in the blanks with the correct words. Choose
from the words inside the box.
1._____________– the natural agent that stimulates sight
ad makes things visible.
2._____________ – allowing light to pass through so that
objects behind can be distinctly seen.
3._____________ – objects that does not allow light to
pass through.
4._____________ - is a narrow but powerful beam of light
5._____________ - made from transparent materials that
transmit visible, ultraviolet and infrared light.
Transparent Laser
Opaque
Light Optical Fiber

31. Directions: Fill in the blank with the correct word.
Write your answer in the blank.
___________ travels in a __________ line when
(1) (2)
passing through a single __________, any
(3)
substance through which a light _________ can
(4)
__________.
(5)

34. B. Direction: Encircle the letter of your chosen
answer.
1. How does laser light travel?
A. curve line C. straight line
B. slant line D. zigzag line
2. How will you describe the size of the laser
light? _____
A. average C. narrow
B. big D. wide

35. 3. Laser light can travel ________ distances and
still focus on a small area.
A. average C. near
B. long D. short
4. Laser light has a great deal of _____ energy.
A. Chemical C. Potential
B. Heat D. Sound
5. Laser have many uses, which is not included?
A. agriculture C. medicine
B. industry D. storing of information

36. WHAT I CAN DO?
ASSIGNMENT:
Directions: Hold the objects in the box in front of a
flashlight or cellphone flashlight. Predict if the light of
the flashlight will pass through the object.

37. REFLECTION
Directions: Complete the journal by writing your answers
on the space provided.
My Journal
I learned that ____________________________________________________
__________________________________________________________________
I realized that ____________________________________________________
__________________________________________________________________
I promised that __________________________________________________
__________________________________________________________________

38. THANK YOU!