Optical Exploration:
The naked eye can only see so much. Our world is full of optical specters including lenses. A study in 2012 stated that 61% of the human population needs glasses at some point in their life. This is physic right over your nose, literally. Imagine seeing a world in a different view. With lenses you can. Let's explore the world of optics.
The naked eye can only see so much. Our world is full of optical specters including lenses. A study in 2012 stated that 61% of the human population needs glasses at some point in their life. This is physic right over your nose, literally. Imagine seeing a world in a different view. With lenses you can. Let's explore the world of optics.
The studies of light is an bottomless well. Ancient Greek philosophers like Socrates and Plato believed vision ensued from streamers and filaments releasing from the eye when it makes eye contact with an object. All philosophers thought light consisted of particles except from the Greek philosopher Empedocles. He thought that light traveled in waves. A Dutch scientist, Christian Huygens, argued this theory because light doesn't spread like waves. He supported the particle theory. In 1905, Albert Einstein publicized the photo electric effect that states light is made of particles - massless bundles of electromagnetic energy called photons. Today, we believe that light is part particles and waves.
One of the greatest things light produces is color. Color is necessary to express our moods. Color is actually the reflection of light. Atoms and molecules vibrate around nucleus with electrons. When electrons oscillate at different frequencies, the produce different colors. When the amplitude of the oscillations is large, light is absorbed. This is the resonant frequencies. Above and below the resonant frequencies, light is reflected. Most materials absorb light though. Now let's apply our knowledge. If a material absorbs all light but red light, then the material reflects red light. The object would then be classified as the color red. Materials that absorb all light and reflect none are considered black. Materials that reflect all visible frequencies of light, it will be the same color as the light that shines on it.
Different frequency of molecules give you different colors. This can be explained in the electromagnetic spectrum:
Mirrors:
According to the Law of Reflection, reflected waves travel back in the direction that it came from. In regards to mirrors, the infinite amount of light rays follow the Law of Reflection. Diverging rays spread apart to create a virtual image in the mirror, even though light does not start there. A concave mirror portrays a stretched image while a convex mirror portrays a squished image. The reflected light enters your eye the same way it would if there was no mirror, so you can't tell the difference in appearance between the actual and virtual image.
According to the Law of Reflection, reflected waves travel back in the direction that it came from. In regards to mirrors, the infinite amount of light rays follow the Law of Reflection. Diverging rays spread apart to create a virtual image in the mirror, even though light does not start there. A concave mirror portrays a stretched image while a convex mirror portrays a squished image. The reflected light enters your eye the same way it would if there was no mirror, so you can't tell the difference in appearance between the actual and virtual image.
Diffuse and Specular Reflection:
Diffuse reflection is when light reflects in all directions on a rough surface. Specular reflection is when the light reflects from the same angle of incident. Both follow the Law of Reflection, but the different elevation of a surface can change the rays' directions. There are two types of surfaces: polished and diffused. A polished surface reflects light in the same angle the ray entered. This is called specular reflection. A rough surface is so varied in elevation, that the light rays are distributed in all directions. This is diffused reflection. A long wavelength still considers moderately bumpy surfaces polished surfaces because there are less points of contact. For short wavelengths, it is harder to fin a polished surface since it contacts at many different places. For example, long radio waves consider an open mesh parabolic dish a polished surface.
Diffuse reflection is when light reflects in all directions on a rough surface. Specular reflection is when the light reflects from the same angle of incident. Both follow the Law of Reflection, but the different elevation of a surface can change the rays' directions. There are two types of surfaces: polished and diffused. A polished surface reflects light in the same angle the ray entered. This is called specular reflection. A rough surface is so varied in elevation, that the light rays are distributed in all directions. This is diffused reflection. A long wavelength still considers moderately bumpy surfaces polished surfaces because there are less points of contact. For short wavelengths, it is harder to fin a polished surface since it contacts at many different places. For example, long radio waves consider an open mesh parabolic dish a polished surface.
Refraction:
Light can travel in different speeds depending on the density of its medium. When light rays go from one medium to another, they change speed therefore changing the direction of the light rays. For example, a pencil seems bent in water because water is denser than air. Therefore, the speed of light decreases and the direction of the rays change. This is called refraction of light.
Atmospheric refraction is when light changes speed in the atmosphere. Light travels through air only 0.03% slower than in a vacuum, but that can make a big difference with light. On hot days, air contacting the ground is hotter therefore particles move faster including light. This can create a bend in light from the eye, creating a mirage. You can see an example below:
Light can travel in different speeds depending on the density of its medium. When light rays go from one medium to another, they change speed therefore changing the direction of the light rays. For example, a pencil seems bent in water because water is denser than air. Therefore, the speed of light decreases and the direction of the rays change. This is called refraction of light.
Atmospheric refraction is when light changes speed in the atmosphere. Light travels through air only 0.03% slower than in a vacuum, but that can make a big difference with light. On hot days, air contacting the ground is hotter therefore particles move faster including light. This can create a bend in light from the eye, creating a mirage. You can see an example below:
Lenses:
Lenses have a very precise design. A piece of glass with the exact right shape bend parallel rays of light so they cross and form an image. This is an example of a lens. There are two type of lenses: diverging and converging. A converging lens is thickest in the middle causing parallel rays to converge to a focus. A diverging lens is thinnest in the middle causing parallel rays to diverge or spread. The virtual image is the object between the focal point and the lens. The real image is the object outside of the focal point. Below are examples of each lens (F = Focal Point).
Lenses have a very precise design. A piece of glass with the exact right shape bend parallel rays of light so they cross and form an image. This is an example of a lens. There are two type of lenses: diverging and converging. A converging lens is thickest in the middle causing parallel rays to converge to a focus. A diverging lens is thinnest in the middle causing parallel rays to diverge or spread. The virtual image is the object between the focal point and the lens. The real image is the object outside of the focal point. Below are examples of each lens (F = Focal Point).
Diffraction:
Huygen's Principle states that every point on a wave front can be considered as the new point source of secondary waves. Basically, a wave front is made up of tinier wave fronts. This can be applied to the concept of diffraction. Diffraction is the bending of waves around a barrier. A narrow slit would spread light rays more than a wide opening due to diffraction. Below is a diagram of Huygen's Principle and how it relates to diffraction:
Huygen's Principle states that every point on a wave front can be considered as the new point source of secondary waves. Basically, a wave front is made up of tinier wave fronts. This can be applied to the concept of diffraction. Diffraction is the bending of waves around a barrier. A narrow slit would spread light rays more than a wide opening due to diffraction. Below is a diagram of Huygen's Principle and how it relates to diffraction:
Color, lenses, and light and its behavior are around you all the time. Understanding how these things work are truly fascinating as you look around at our colorful, light filled world. I can't imagine what our worlds would be like without light.