Category: Physics

Bearing stress

Bearing stress

Bearing stress

03/18/17

“What happens when stress acts upon an area perpendicular to the axis of an object?”
The most well-known types of engineering stress are normal stress, (when a stress acts upon an area parallel to the axis of an object) and shearing stress (when a stress acts perpendicular to said axis). But is there a third type of stress? Well, to know more, let’s scientifically analyze such a phenomena. Well, when two bodies are in contacts and move in opposite directions, they will exert a force upon one another. Furthermore, this force will be distributed over their area of contact, creating a stress. This form of stress is known as a bearing stress and can be symbolically described using the equation (sigma)_ bearing = force/area

Latent heat

Latent heat

Latent heat

03/17/17

 

“How do we quantify the energy released or absorbed during a constant temperature process?”
When we deal with energy and heat problems, we typically think of the system of having a change in temperature. However, when it comes to phase transitions it is possible to have a change in energy of a system without a corresponding change in temperature. So how have scientists and engineers decided to describe this phenomenon? Well, after much research into the subject, this process has been termed latent heat and is proportional to the energy required to change the phase of a substance divided by its mass, which can be symbolically described by the equation L=q/M.

Critical angle

Critical angle

Critical angle

03/07/17

“Can we use refraction to make reflection?”
Refraction is a common physical phenomenon, and we know that if light from a denser medium passes into a lighter medium then it will bend further away from the normal angle. However, is it possible that this angle can bend so much that it will actually go back into the incident medium? Well, let’s use our scientific mindset to investigate this question. We know that light passing between two mediums behaves as dictated by snell’s law, or n1sin(1)=n2*sin(2). If we were to arrange this equation to find for 2, we would arrive at 2=sin(n1*sin(1)/n2)-1. Now if we analyze this equation, we can realize that if were to have the ray of light incident at an angle 1such that the output would be 90 degrees, the light would not pass to the other side! Physicists have termed this angle the critical angle and is used heavily in fiber optics, where light is trapped in and passes through a long tube of wire.

Interferometers

Interferometers

Interferometers

03/06/17

“How can we produce a controlled chromatic aberration for study?”

 

Chromatic aberration is one of the most perplexing phenomena in the study of optics. However, creating controllable versions for laboratory study are extremely difficult to accomplish. So how can we make a machine that will be able to make adjustable chromatic aberrations at our will? Well, let’s use our engineering mindset to solve this scientific problem. Well, we know that if we were to pass monochromatic light into transparent glass at an angle then some will be reflected and some will be refracted. This creates two beams of light of identical wavelength for us to study. Now, let’s take this a step further. We need to pass these beams of light back to each other so that they interfere, which can be accomplished by placing mirrors in the path of beams. So what if were to take this system and bring it into a reality? This machine is known as an interferometer, and is used in physics labs all over the world to study the intricacies of chromatic aberration.

Diffraction grating

Diffraction grating

Diffraction grating

03/04/17

“What happens when we shine wave through a large chain of small holes?”
Optics is a most enjoyable branch of science. And one of it’s most peculiar facets occurs from a most simple setup. Suppose that one were to have two sheets of metal facing each other. Then one were to cut a large number of rectangular holes evenly spaced throughout one sheet and finally shine a light upon it. What exactly would happen? Well, let’s use our knowledge of science to figure this out. We know that when a ray of light hits a small opening, a wave will be produced. And we also know that when waves interfere with one another, a superposition will be produced. Now let’s apply this to this physical system. The light incident upon these holes will produce many waves, which will then collide on the opposing sheet. These waves will then either interfere constructively or destructively with one another, causing a pattern of bright and dark spots to occur. These spots will be spaced from one another in a ratio corresponding to the wavelengths of the light beams, the width of the diffraction gratings, and the distance between the two sheets

Ray tracing

Ray tracing

Ray tracing

02/28/17

“How can we represent light rays interacting with lenses and mirrors?”
Even through the field of optics is a deep one, it is also quite simple. At its fundamental core, it is about the properties and interaction of light. This includes the subset of mirrors and lenses. So wouldn’t it be logical that we should develop a system to represent the interaction with lenses and mirrors? To start off, let’s construct the mirrors, lenses, and objects that we would like to work with. Next, label the center and focal point of the mirrors and lenses. Afterward, draw lines emanating from the object, and have it realistically interact with the optical instruments. Then draw the resulting image where all of the rays converge onto one another. This process is known as ray tracing, and is one of the most important tools used by researchers and students in optics.

How images form in the eye

How images form in the eye

How images form in the eye

02/25/17

“How exactly do we see things with our eyes?”
Everything that we perceive in this world is formed through our eyes. However, have you ever wondered how images can physically form in these biological objects? Well, let’s analyze this question scientifically to find out. If one were to take an eyeball and cut it in half through the midpoint of the pupil, they will find a lens just behind the cornea. If you were to then shine parallel light beams through this lens, then you would find that all of the light would focus on to the backside of the eye. The back of the eye will then transmit information to the brain, which will invert the image “in the mind’s eye” enabling us to see!

Shear Stress

Shear Stress

Shear Stress

02/24/17

“What happens when stress is applied parallel to the surface area of a material?”
Any force acting upon a three-dimensional object will produce an internal stress. However, how do engineers classify the types of stress that are parallel to the material’s surface area? Well, after many years of research, this phenomenon has been classified as a shear stress. A shear stress will produce a shear strain in the object proportional to the object’s modulus of rigidity, which can be symbolically represented with the equation (Tau = G*(Gamma), with (Tau) being the shear stress (Gamma) being the shear deformation and g being the modulus of rigidity. The higher a material’s shear strength is, the more it will be able to resist shear strength.

Refracting telescope

Refracting telescope

Refracting telescope

02/22/17

“How do old-school telescopes work?”
Telescopes are one of the most amazing machines that humanity has constructed. Not only have they become a symbol for scientific endeavor but a cultural landmark as well. However, have you ever wonder how they worked (specifically the old-school ones)? Well, let’s use our engineering mindset to figure out this scientific device. If we were to uncover the case of these machines, we would find two convex lenses. Now, if we were to trace a ray diagram through the lenses, we would find something very interesting. First, the incoming light from the object would converge onto a real image on the opposite side of the first lens. The light from this image would then be received by the second lens, which shifts the light’s direction in such a way that their paths would converge on the receiving side of the lens, forming a magnified virtual image, therefore creating an enlarged image that the human eye can see. This form of a telescope is called a refracting telescope, and has been used since the days of Galileo!