LIGHT ENERGY INVESTIGATION
Questions:
Experimental Design:
Results:
- Does light have energy?
- If it does, what other forms of energy does it turn into?
- What is the relationship between the source of light and the distance of the measuring device?
Experimental Design:
- To test this what we're going to do is turn on the light to see if the radiometer spins. If it does, then light has energy.
- Another test that we're going to do is take the thermometer and measure the temperature before I turn on the light, then measure the temperature after I turn on the light. If the thermometer changes, then light has heat energy.
- Then, what we're going to do is take the radiometer and place it at 10 cm, then time how long it takes to rotate one time round from rest. Then repeat every 10 cm back.
- Then finally, what we're going to do is take the temperature at every 10 cm from the light.
Results:
- Experiment 1:
- Without the light on, the radiometer was at rest. However, when we turned on the light, the radiometer began to spin quickly. Therefore, light has energy.
- Experiment 2:
- Without the light on, the thermometer was set at 24 degrees.
- When I turned on the light, the thermometer increased to 26 degrees after 1 minute. Therefore, light can turn into heat energy.
Experiment 3: How long it takes the radiometer to spin 1 time at 10 cm increments.
(Data can be found as the caption for each picture).
(Data can be found as the caption for each picture).
Experiment 4: What is the temperature as we increase our distance every 10 cm.
Reflection:
Claim: Based on the evidences collected, answer the three questions.
Evidence: Support your answers (claim) with evidence collected.
Reason: Explain why you think this is the case, and how it all works.
How this works:
The radiometer detects radiant energy, this is also known as light. Light is an electromagnetic wave that "radiates" out from its source. Meaning, it is emitted from its source, and it radiates out when it transmits through various different mediums from its source.
Light has a much wider spectrum of light than just visible light (ROYG.BIV). Light also includes bands of light such as radio-waves, microwaves, infra-red, ultra-violet, x-ray and gamma forms of "radiation".
Claim: Based on the evidences collected, answer the three questions.
Evidence: Support your answers (claim) with evidence collected.
Reason: Explain why you think this is the case, and how it all works.
How this works:
The radiometer detects radiant energy, this is also known as light. Light is an electromagnetic wave that "radiates" out from its source. Meaning, it is emitted from its source, and it radiates out when it transmits through various different mediums from its source.
Light has a much wider spectrum of light than just visible light (ROYG.BIV). Light also includes bands of light such as radio-waves, microwaves, infra-red, ultra-violet, x-ray and gamma forms of "radiation".
Light, when it is absorbed, will turn into thermal energy, also known as HEAT!
This is why a black surface will always be hotter than a light colored surface. Black will absorb all bands of visible light and turn it into heat, while white surfaces reflect light and not get as hot. This is why the black thermometer strip rose in temperature when the light was shining on it. It. What it did was it absorbed the light energy and converted it into heat energy - making the temperature rise.
You may have noticed that the radiometer has 4 fins inside; and on each fin, there is a white side and a black side. Since black absorbs light energy (through a heat transfer called "radiation"), and white reflects light energy, what happens is the light will hit both fins at the same time. However, since the black side will absorb the light and turn it into heat energy, that heat energy gets absorbed by the atoms that are near the surface of that black fin and it will "kick" off (due to a heat transfer called conduction"). This atomic "kick off" is what propels the fin to go one way, while the atom(s) goes the other way. This is due to newtons 3rd law of motion called inertia. You may have heard it before as "for every action, there is an equal and opposite reaction".
Lastly, you may have noticed that the closer to the light source, the faster the radiometer spun and the hotter the thermometer got. This is due to the lights intensity! The closer to the light, the more intense the light was; the farther out, the less intense.
You can think of intensity as a bunch of light beams that's able to squeeze into a square area. The farther out you go, the light beams spread out (much like a wave on a pond), which means there are less light beams going through the same area, or another way of looking at it, it's the same amount of light beams that hit a much broader area.
This is why a black surface will always be hotter than a light colored surface. Black will absorb all bands of visible light and turn it into heat, while white surfaces reflect light and not get as hot. This is why the black thermometer strip rose in temperature when the light was shining on it. It. What it did was it absorbed the light energy and converted it into heat energy - making the temperature rise.
You may have noticed that the radiometer has 4 fins inside; and on each fin, there is a white side and a black side. Since black absorbs light energy (through a heat transfer called "radiation"), and white reflects light energy, what happens is the light will hit both fins at the same time. However, since the black side will absorb the light and turn it into heat energy, that heat energy gets absorbed by the atoms that are near the surface of that black fin and it will "kick" off (due to a heat transfer called conduction"). This atomic "kick off" is what propels the fin to go one way, while the atom(s) goes the other way. This is due to newtons 3rd law of motion called inertia. You may have heard it before as "for every action, there is an equal and opposite reaction".
Lastly, you may have noticed that the closer to the light source, the faster the radiometer spun and the hotter the thermometer got. This is due to the lights intensity! The closer to the light, the more intense the light was; the farther out, the less intense.
You can think of intensity as a bunch of light beams that's able to squeeze into a square area. The farther out you go, the light beams spread out (much like a wave on a pond), which means there are less light beams going through the same area, or another way of looking at it, it's the same amount of light beams that hit a much broader area.
If you were to compare it to ripples on a pond, the closer you are to the source, the higher the amplitude of the ripple, and it's more "intense". The further out you go, the energy along the ring becomes more spread out, which makes the amplitude diminish - which means it's less "intense".