Category: Physics

Radius of gyration

Radius of gyration

Radius of gyration

02/13/17

“What would happen if we were to take the entirety of the object’s mass and concentrate it at a point?”
During one’s study of statics, one will have to work with the mass and moment of inertia for objects. However, could there be any ways in which we could simplify our calculations just a tad bit? Well, let’s think about it. Everything could be much simpler if we were to take the mass of the object and concentrate it at a single point away from the axis so that the resultant moment of inertia would be equivalent to original moment of inertia? This is the fundamental idea behind a concept known as the radius of gyration, and can be found with the equation k=Im, with k being the radius, I being the moment of inertia, and m being the mass.

Nuclear power generation

Nuclear power generation

Nuclear power generation

02/12/17

“How exactly is Nuclear power generated?”
We hear about nuclear power very frequently in our lives. However, how exactly does it work? Well, to start let’s look at the process. The fundamentals of nuclear power start with two elements, uranium-238 and uranium 235. U238 composes the majority of uranium in a nuclear power plant, but perhaps the most important of the two is u235. Uranium 235 is very unstable and will decompose rapidly through nuclear fission. When U235 decomposes, it’s neutrons will be thrust throughout space. When these neutrons collide with U238, the element will be shattered into a stream of different particles, which will hit other elements. This quickly sets up a chain reaction which produces a large amount of heat. This heat is then used to boil water to generate steam to move a turbine which generates electricity.

Focal point

Focal point

Focal point

02/07/17

“Why is the point that light will hit for a concentrated solar power system so special?”

Concentrated solar power is famous for its use of parabolic cylinders to concentrate solar energy. However, what special physical property gives it its strength? Well, let’s use a little bit of scientific thinking to find out. Since all light rays contain energy, and these solar systems work by absorbing energy from concentrated sunlight, would it not be logical that we would just place the water at the point of maximum sunlight? If we do enough experimentation, then we will find out that this point is where all of the rays will converge! This point has been termed the focal point and is used for a variety of other applications ranging from photography to telescopes.

The physics of a football tackle

The physics of a football tackle

The physics of a football tackle

02/05/17

“How do the laws of physics affect football tackles?”

 

Because of the excitement for the super bowl stateside, a fan recently asked for an article about the science of football.

 

If you are from the United States, then you have probably seen or heard about a game called “football” where people divided onto two teams will fight each other for control of a prolate spheroid shaped ball using tackles. However, have you ever wondered about how one can make an optimal tackle? Well, it turns out that all you need is a rudimentary knowledge of physics to find out.

        Every object in the universe has a property called a center of mass, or the location of the mean position of matter in a body. When a force is applied on an object which does not go through the center of mass, a torque will be induced, causing a rotation on said body. So now let’s put this theoretical framework into practice. The average human male has their center of mass located slightly above the navel. When one football player tackles another in this area, the player will simply be moved in the direction of the tackle. But if the player were to give a tackle below this zone, a torque would be induced that would completely throw off the player! Luckily, professional coaches have taken note of this, and use this scientific knowledge to advise linemen to stay close to ground while running, making it far more prohibitive for a disabling torque to be thrust upon them!

Science always shows up in the most marvelous ways in our everyday life, and it goes to show that a small bit of knowledge of it can go a long way.

P and N-type semiconductors

P and N-type semiconductors

N-type semiconductors

02/02/17

“What are the fundamentals of the fundamentals of solar cells?”
Solar cells are one of the most magnificent devices that humanity has conjured. However, what exactly makes them tick? To find out, let’s go take a look. If one were to analyze a solar cell with a magnifying glass so powerful that it could see in the microscopic level then we would find a multitude of small, three terminal devices. These devices are known as Transistors and have very special properties. Specifically, it can work as a switch without moving parts! However, before we understand transistors, we must understand what cause them to work. Half of the composition of transistors are composed of objects known as P-type and N-type semiconductors. P-type semiconductors hold an impurity of boron[B], which holds one less electron than silicon, while N-type semiconductors are  have a small impurity of phosphorous [P], which holds an extra electron than silicon. When combined, these semiconductors will have more mobile charges and can conduct current better.

Spherical Sun Power Generators

Spherical Sun Power Generators

Spherical Sun Power Generators

“Is the only thing we need for the next solar power revolution  just a simple change of geometry?”
The current design of solar panels have a distinct bottleneck; their rectangular geometry leaves them inefficient for obtaining solar power from the sun since the sun’s rays will be in a sub-optimal direction for most of the time. Solar trackers can also be inefficient and are prone to damage in the rain, so how can we completely transform the way we collect solar power? Well, let’s use our engineering mindset to figure this out. Our goal is to make the design of our solar producing unit so that the sun can be in an optimal angle at all times. If we think back to our geometry class, then we will remember that a sphere is symmetric from all directions. With this knowledge, the German architect Andre Broessel created a Spherical Sun Power Generator. The setup works as follows: A supporting structure will house a spherical lens. This spherical lens will have a dual tracking system structure at the back of it. In this tracking system will be solar cells, which will receive ample sunlight as a result of the focusing effect from the spherical lens. These spherical sun power generators allow for twice the conventional yield in a much smaller surface area, allowing it to even absorb the reflected sun light from the moon!

Internal energy

Internal energy

Internal energy

12/08/16

“How can we quantify the energy of internal molecules in a system?”

 

There seems to be a problem. Scientists and engineers often need to analyze the energies associated with objects. However, the atoms of all material are not contiguous with one another but are moving in many directions, each with their own potential and kinetic energy. So how can we quantify such system? Thankfully, after many decades of long research, a most useful concept known as internal energy has been developed. The internal energy of a system is defined by the summation all of the energies arising from the microscopic components of a system, which is often summarized symbolically by the equation U_internal = U_potential+U_kinetic, with U standing for energy

Hess’s law

Hess’s law

Hess’s law

12/05/16

“How can we find the change in enthalpy for a chemical reaction without actually performing the reaction?”

Finding the change in enthalpy for a chemical reaction is a rather straightforward procedure, one simply carries forward with the necessary steps and measures the temperature before and after the reaction took place. However, some reactions take an extraordinary long time to perform, or their process is highly volatile. So how can we find the change in enthalpy for such reactions? Well let’s think about it. We know that if we were to take one chemical reaction and reverse it, then the resulting change in enthalpy would reverse in sign. And we know that if we add one element of a chemical equation to the opposite side of an equation containing that element, then they would cancel out. So what if were to take the results of some reactions that we already know, modify them if necessary, and then add them together to fashion the equation of the reaction that we desire? This is the operating principle behind Hess’ law.

To illustrate, let’s examine the reaction Mg(s) + H2O(l) → MgO(s) +H2(g). Since Mg does not react with water, completing this experimentally would be a nightmarish process. However, we can easily obtain the results for Mg(s) +2HCL(aq) → MgCl2(aq) + H2 and MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O. If we were to take the former equation and subtract the latter from it, we would be able to obtain our desired equation. All we need to do is obtain the change in enthalpies for these reactions, and then proceed forward with the mathematics, and next thing you know we would obtain our necessary results!

Change in Enthalpy

Change in Enthalpy

Change in Enthalpy

12/04/16

“How can we measure the change of energy in a thermodynamic system when the system itself changes?”

 

All thermodynamic systems have the summation of the parts of their energy represented by enthalpy. However, the universe is almost never in a static state, and is always changing. Consequently, all thermodynamic systems will be in perpetual change as well. And it turns out that this change in enthalpy has very practical results for scientific use. A change in enthalpy can be quantitatively described by taking the difference of the enthalpy of the system after the change and before the change. If the  enthalpy has gone up, then that means that energy must have been added to the system, making it an endothermic process. If the enthalpy has gone down, then heat was removed from the system and it was an exothermic process. The change in Enthalpy is often symbolically represented using a (delta)H