LEYTE NORMAL UNIVERSITY

SCIENCE UNIT

Tacloban City

Name: ______Cr/Yr/Sec.: ______Date: ______Group #._____

Subject & Sched: ______Leader’s Name: ______

Activity # 1.2

PROPERTIES OF LIGHT

Objective: Observe the wave properties of light-reflection, refraction, diffraction and interference.

Materials:

Vertical full length mirrorDiffraction gratingMeter stick

Red and green plastic cellophaneMasking tapeCylindical box

Glass prismsunlight

Procedure:

  1. Learning Station 1, “the mirror on the wall”
  1. Get a vertical full length mirror.
  2. Stand at arms’ length in front of it.
  3. Place a small piece of masking tape on the image of the top of your head.
  4. Put the other piece of tape on the mirror where your toes are seen.
  5. Using a meter stick, measure the distance from top of your head to your toes.
  6. Stand 3 meters from the mirror and repeat steps 2and 3 with a partner to assist you in making marks.
  7. Move farther away and closer and repeat the procedure.
  1. Learning station 2, “white light through a prism”
  1. Look at something on the sunny side using a prism.
  2. Turn the prism slowly until you see different colors of light.
  3. Observe that the colors are in bands.
  4. While you hold the prism steady, have a pattern. Outlines the band of colors.
  5. Label the colors.
  6. Beginning with red try to arrange the colors ion order.
  1. Learning Station 3, “diffraction and interference of light”
  1. Get a cylindrical box.
  2. Mount the diffraction grating at the end of the box.
  3. Provide a slit for viewing on the other end.
  4. Go to a place where there is a light source.
  5. Look at the light source through the eyepiece with the diffraction grating.
  6. Look at the right and left of the inside wall of the cylindrical box.
  7. Observe.
  8. Repeat step 4 – 6, first with the red cellophane in front of the light source.
  9. Repeat step 4 and 6 with the green cellophane.
  10. Hold the diffraction grating against the light.

Guide Questions:

  1. Learning Station 1
  1. In step 3 and 4, how does the distance between the pieces of tape on the mirror compare with your height?

______

  1. In step 6 and 7, what did you discover?

______

  1. Does the location of the tape depend on your distance from the mirror?

______

  1. How are light rays reflected?

______

  1. Define reflection?

______

  1. Learning Station 2
  1. Can you name the colors you observed?

______

  1. Compare the width of the bands.

______

  1. Will the order of colors change if you turn the prism? Explain your answer.

______

  1. Define refraction?

______

  1. Learning Station 3
  1. What is diffraction grating?

______

  1. In steps 4 – 6, write your observations.

______

  1. What image is produced when there is red cellophane in front of the light source?

______

  1. What image is produced when there is green cellophane in front of the light source?

______

  1. Write your observations when you hold the diffraction grating against the sky.

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  1. Define diffraction.

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  1. What is interference?

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Generalization

What are the different properties of light? Explain each.

______

Application

Explain the occurrence of rainbows. Why do we see different colors?

______

LEYTE NORMAL UNIVERSITY

SCIENCE UNIT

Tacloban City

Name: ______Cr/Yr/Sec.: ______Date: ______Group #._____

Subject & Sched: ______Leader’s Name: ______

Activity # 1.3

HOW ARE SOUND WAVES PRODUCED?

Objectives: Explain how sound waves are produced, transmitted and propagated.

Materials:

1 – 2 meter string2 chairspair of scissors

Small piece of paperpencilmusic player

Procedure:

  1. Touch your throat.
  2. Talk and feel the vibration of your vocal cords.
  3. Speak while your mouth is widely opened.
  4. Speak while your mouth is slightly opened.
  5. Observe the sound produced.
  6. Listen to a recorded music for 15 minutes.
  7. Observe how a sound wave reaches your ears.
  8. Set two chairs about 125 cm apart.
  9. Tie a string tightly from the back of one chair to the other.
  10. Cut a small piece of paper.
  11. Fold over into half so it looks like an open book.
  12. Hang the piece of paper on the string near one end of the chair by folding the paper.
  13. Near the end, hit the string hard with the pencil. You have put energy into the string by making it move up and down.
  14. Observe what happens to the paper.
  15. Continue hitting the string with the pencil.
  16. Observe what happens to the paper.

Guide Questions

  1. Describe what you observed when you touched your throat while speaking.

______

  1. Is there any difference when you speak with mouth slightly opened and when it is opened wide? If yes, in what ways do they differ?

______

  1. How does sound from the recorded music travel to your ears?

______

  1. What happens to the paper as you hit the string with a pencil?

______

  1. What moves the paper from the string? Explain.

______

Generalization

How is sound produced through the vocal cords?

______

Application

Explain why troops break steps when crossing a bridge?

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