LIGHT WAVES INVESTIGATION
initial investigation: observing A pencil or ruler in water
Have students make some observations of a ruler stuck on the opposite side of the plastic tub filled with water. Have them draw a model of what they are doing and seeing.
Followup investigation
In this lab, we're investigating some of the wave properties of light by examining why a pencil looks different in water.
Phenomena:
Question(s):
Experimental Design:
Results:
Phenomena:
- A ruler looks bent in water at different angles.
Question(s):
- Why does it do that?
- How much does light bend in water?
Experimental Design:
- Take a laser and measure the angle it goes into the water.
- Measure the angle the laser takes as it goes through the water.
- Record the results on a data table & graph the results.
- Calculate the angle of refraction index.
- Observe any other phenomena along the side.
- Apply my findings to the pencil phenomena by making a model.
Results:
photos of Students doing the lab
Photos of refraction & reflection
my model thus far
Draw a model that at best illustrates the behavior of light with respects to the ruler in the water.
Provide a possible explanation based on your findings with the laser light lab.
Provide a possible explanation based on your findings with the laser light lab.
Reflection: My understanding thus far:
(What this means is that I'm aware that I may have some limitations of my insight, and that there is more to learn).
Why the ruler looks short at a low angle and a little longer at a higher angle is due to the refraction of light. When light hits the object, light then travels through the water and bends when it hits the air. The reason why this is the case is because light travels slower in water than it does air.
The virtual image is made when the refracted light is extended or projected from the eye to the object (ruler). This is where the bottom of the ruler appears to be, but is not in reality.
(What this means is that I'm aware that I may have some limitations of my insight, and that there is more to learn).
Why the ruler looks short at a low angle and a little longer at a higher angle is due to the refraction of light. When light hits the object, light then travels through the water and bends when it hits the air. The reason why this is the case is because light travels slower in water than it does air.
The virtual image is made when the refracted light is extended or projected from the eye to the object (ruler). This is where the bottom of the ruler appears to be, but is not in reality.
Finish Challenge:
The question on this challenge was to be able to explain why the ruler looked nearly regular sized when we were looking down on it, and why it looked small when we were near the water level?
The reason why it appears small when you are near the waters surface is due to a higher level of refraction of light, when the light goes from the water to the air.
How it works:
This is why, when you look at a fish under the water, where you think it is, it is not really there, but closer to you than you realize.
The question on this challenge was to be able to explain why the ruler looked nearly regular sized when we were looking down on it, and why it looked small when we were near the water level?
The reason why it appears small when you are near the waters surface is due to a higher level of refraction of light, when the light goes from the water to the air.
How it works:
- Light from the source hits the base of the ruler.
- Next, the light travels through the water.
- Once the light travels through the air, it bends because it travels faster in air than it does water.
- Last, it hits your eye.
- My understanding so far, (meaning, there could be more to the story if I find out more information), If you were to draw an imaginary line from the light hitting your eye towards the ruler, the apparent image from the top of the water to the base of that imaginary line, that is where the base of the ruler would appear to be. Meaning, I would fit the submerged portion of the ruler in the space between the top of the water to the base where the apparent image line intersect.
This is why, when you look at a fish under the water, where you think it is, it is not really there, but closer to you than you realize.
Points of interest learned from the lab.
From this lab, we learned that:
Vocabulary Terms
Resources:
From this lab, we learned that:
- Light is a wave and behaves like a wave. (As you progress in your learning of physics, you'll learn later about the particle nature of light - but for now, we're keeping it simple).
- Light can be bent (Refraction Index)
- Objects may appear bent, when they really are not. This is called refraction.
- Water slows down light, which causes light to bend. This is the basis of refraction.
- Water also simultaneously reflects light.
- In order to see the laser light, you must add small particles into the watery mix which scatters the light. This makes it more translucent than transparent.
Vocabulary Terms
- Reflection: When light come in, hits the surface and goes out the same angle it came in.
- Refraction: When light enters into the other material (medium) and gets bent due to a change in the speed of light.
- Transmission: When light goes through the material.
- Emission: The source of light when it is made.
- Absorption: When light no longer transmits through the material.
- Scattering: When light goes in different directions after hitting an object.
- Diffusion: When light splits based on its wavelength
- Opaque: When light does not go through the material, and an image is not seen.
- Translucent: When light is scattered in the medium and light or a fuzzy image is seen.
- Transparent: When light is not scattered in the medium and there is a clear image seen.
Resources:
- http://web.mit.edu/knazemi/www/advancedExperiment1.htm
- https://www.kullabs.com/classes/subjects/units/lessons/notes/videoplay/743/2647