SNC 2P1 – Optics Lab # 1 – Properties of Light

/40 MARKS

Name:

Station 1 – Viewing the Visible Spectrum /5 MARKS

Materials: a ray box, two triangular prisms, a sheet of white paper

Procedure:

1.Place one prism on a sheet of paper. Trace its outline.

2.Shine a single beam of light from the ray box on one side of the prism. Adjust the position of the ray box until a clear spectrum is visible on the other side of the prism.

3.Identify the colours that you can clearly see in the spectrum.Mark the location of each colour on the paper.

Questions & Analysis:

  1. Draw and label your diagram in the space provided. (2 marks)
  1. How many of the seven colours were you able to see? Why may not all of the seven colours be clearly visible? (1 mark)
  1. Where can you see this colour spectrum in nature? List two examples. (2 marks)

Station 2 – Seeing the Light /5 MARKS

Materials: a flashlight, a spray bottle filled with water

Procedure:

  1. Place a flashlight on a desk and aim it at the wall. Turn on the flashlight.
  1. Examine the beam on the wall and the air in the path of light from the flashlight to the wall.
  1. Place your hand in the path of the beam and observe the beam.
  1. Spray water from the spray bottle into the air between the flashlight and the location of the beam on the wall.

Questions & Analysis:

  1. Could you see the beam of light just in the air? (1 mark)
  1. What happened to the light beam when you placed your hand in its path? (1 mark)
  1. What did you see when you sprayed the water? (1 mark)
  1. What is necessary in order for you to see light, in general? (1 mark)
  1. Suggest a reason to explain why you could see the light beam only when there was sprayed water in the air. (1 mark)

Station 3 – Reflecting Light /6 MARKS

Materials: an unshielded ray box, a sheet of aluminum foil

Procedure:

  1. Place a smooth piece of aluminum foil flat on a table.
  1. Reflect the beam from the ray box off the aluminum foil.
  1. Aim the light beam so that it is reflected up only the ceiling. Examine the reflected beam.
  1. Now crumple up the aluminum foil. Open the crumpled piece of foil but do not smooth it out again.
  1. Again, reflect the light beam onto the ceiling and examine the reflected beam.

Questions & Analysis:

  1. Describe the shape of the reflected beam on the ceiling when the aluminum foil was flat and when it was crumpled. (2 marks)
  1. Account for the difference in the reflected beam between your two trials. (2 marks)
  1. Draw a diagram of how light was reflected in both the smooth and crumpled aluminum foil. (2 marks)

Station 4 – Writing Reflectively /7 MARKS

Materials: plane mirror, white sheet of paper, pencil

Procedure:

  1. Place the mirror on the upper half of the sheet of paper, using your hand to hold the mirror upward.
  1. While looking only in the mirror, carefully print your name so that it appears correctly in the mirror, not worrying about what it looks like on the page. You may have to practice a few times until you are able to do this successfully. Also, try writing with the hand you normally do not use.
  1. Once you are comfortable, use the mirror to print a short (nice) message.
  1. Exchange your message with a partner, and try to decipher it just by looking at the paper. Check the accuracy by using the mirror.

Questions & Analysis:

  1. Describe the appearance of your written name on the paper compared with its appearance in the mirror. (1 mark)
  1. Was writing while looking in the mirror difficult? Why? Which letters did you find more difficult to do? (1 mark)
  1. Did you find it easier writing with one hand than with the other? Suggest a reason why. (1 mark)
  1. From this activity, what general conclusion can you make about how an object and its image in a plane mirror are related? (2 marks)
  1. Leonardo da Vinci was a left-handed Italian artist and scientist born in the 15th century. He used mirror writing in his notebooks when he was writing about his inventions and other ideas. Why do you think he did this? (2 marks)

Station 5 – Producing Images/7 MARKS

Materials: two plane mirrors, a ruler, a protractor, a die, white paper, a pencil

Procedure:

  1. Place two mirrors at right angles to each other at the top of the sheet of paper. Place the die directly in front of the right angle formed by the mirrors. Record how many images you see in the mirrors.
  1. Gently move one of the mirrors, keeping the other one still, changing in the angle between the two mirrors, until you see four complete images. Draw lines on the paper at the base of the two measures so you can measure the angle between them. (Label this line “4”)
  1. Now gently move the same mirror, keeping the other one still until you see five images. Again, draw lines on the paper. (Label this line “5”)
  1. Do the same for finding 6, 7, 8, 9, 10, 11, 12 and 13 images and so on (until it can no longer be done), while labelling the lines.

Questions & Analysis:

  1. How many images were visible when the mirrors were at right angles to each other? (1 mark)
  1. What was the angle between the mirrors for: (2 marks)

a)4 images:

b)5 images:

c)6 images:

d)7 images:

e)8 images:

f)9 images:

g)10 images:

h)11 images:

i)12 images:

j)13 images:

  1. What was the total number of images that you were able to count? Why were you not able to exceed this value? (2 marks)
  1. A hall of mirrors in an amusement park seems to produce an infinite number of images when you look into it. This effect is also commonly seen in elevators that have two plane mirrors on opposite walls. Suggest a reason why elevator designers use this effect. (2 marks)

Station 6 – Reflecting Light Off a Plane Mirror /10 MARKS

Materials: ray box, plane mirror, pencil, ruler, protractor, sheet of paper

Procedure:

  1. Draw a dashed line across the centre of a sheet of paper. Place a mirror on this line. The back of the mirror should be on the line, not the glass part of the mirror.
  2. Aim the incident ray on the mirror at an angle of your choosing, and mark the path of this line on your paper, and label it “incident ray”
  3. Draw a normal to the mirror, and label this line “normal.”
  4. Look at the location of the reflected ray. Mark the path of this line on your paper, and label it “reflected ray.”
  5. Use your protractor to measure the angle of incidence and the angle of reflection.
  6. Repeat steps 1-5 using the same normal, but aiming the incident ray to the normal at a different angle on the same sheet of paper.
  7. Repeat steps 1-5 using the same normal, but aiming the incident ray directly along the normal.
  8. Write all data in the observation table below. (2 marks)

Trial Number / Angle of Incidence / Angle of Reflection
1
2
3

Questions & Analysis:

1. Include your labelled sheet of paper with your lab report. (1 mark)

2. How did the angle of incidence compare with the angle of reflection in the first two trials? (1 mark)

3. When you aimed the incident ray directly along the normal, describe the path of the incident and reflected rays in the third trail. (2 marks)

4. Where might errors occur in this activity, and how could these errors affect your conclusion? (2 marks)

5. What are two sports or activities make use of the reflection rule that you discovered in this activity? (2 marks)