COT 1 SCIENCE - The Path of Light.pptx

Science 4 Quarter 3

1. The Path of LIGHT ANNA KATHRINA C. CERIA Teacher III Pahinga Norte Elementary School

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

3. How does light travel?

4. REVIEW

5. Have you ever tried aiming a flashlight at a distant star on a dark night? Were you able to follow the path of the light to the star you’ve pointed?

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

7. 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 middle 1-piece thick cardboard Observation sheet

8. General Instructions and Rules in Practicing 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.

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

10. What to do: 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. Aim the flashlight/laser through the first hole. Observe what happens. Misalign the 2nd illustration board. Keep the light aimed at the illustration boards. Observe what will happen.

11. 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:

12. 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:

13.  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?

14.  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?

15. 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 printers and scanners. WHAT IS IT?

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

17. • 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?

18. 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 .

19. 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:

20. 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

21. 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)

22. WHAT I HAVE LEARNED? Write TRUE if the statement is correct and FALSE if it is not correct. ______1. Light travels in a straight line when it passes through a single medium. ______2. The light that strikes a thick cardboard bends and find another way to pass through it. ______3. Light rays could not be blocked and they could pass through all types of materials since they travel on a straight line. ______4. A laser is a narrow but powerful beam of light capable of travelling far distances on a straight line.

23. WHAT I HAVE LEARNED? ______5. Optical fibers are used in communication, medicine and industry. ______6. Light rays could be blocked, and they could pass through all types of materials since they travel on a straight line. ______7. Optical fibers can be used in communication, in industry, and medicine. ______8. Light travels in a curve line when it passes through a single medium. ______9. The sun is the main source of natural light. ______10. Light travels slower in the air than through water because air is less dense than water.

24. 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

25. 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

26. 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.

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

28. THANK YOU!