Category: Physics

Spin quantum number

Spin quantum number

Spin quantum number

10/05/16

“How can we describe the angular momentum of an electron?”

 

The orbits of electrons around the central nucleus of an atom is a very complex matter. And because of this, we will have think to think of creative ways to describe the myriad of elements that make it up. So to make things simpler break this problem down into smaller components, such as the angular momentum. When an electron transits around the central nucleus, it has both an angular momentum from the orbit and another one resulting from the spin around it’s own axis. The combination of these two elements will result in a vector quantity called the spin quantum number. The spin quantum number represents the magnitude (½) and the direction 9+ or -) hat the angular momentum of the current electron. When electrons enter into subshells, they enter each orbital that is currently unoccupied. If the elements only has unpaired electrons, then this spin quantum number will be considered positive, and if the electrons begin to pair up, then the spin quantum number will be considered negative.

Quantized energy

Quantized energy

Quantized energy

10/04/16

“How does energy work on the quantum scale?”
Energy is a most bewildering phenomena. It is the very thing that literally drives the physical universe, yet we have no complete understanding of it. I fact, our understanding of energy breaks down even further when we go into the quantum world. On this scale, energy is not a continuous but a discrete phenomena! This means that energy comes in chunks instead of being “On a scale”. Let me elaborate using a metaphor. on the human scope, energy is measured like the volume of a liquid, it’s size can occupy a whole range of values, going into myriads of different decimals places, while on the quantum magnitude, energy is measured like drops of the liquid, being indivisible (for example, you can’t have half a drop of water). Energy in the quantum world through waves of light in units called quanta, Which are equal to a measurement called Planck’s constant (numerically equivalent to 6.63*10^-34 joules seconds) times the wavelength of the light. This relationship can be symbolically represented as E=h*lambda, with E being energy h being Plank’s constant, and lambda being the wavelength of light.

Hydrophobic substances

Hydrophobic substances

Hydrophobic substances

10/03/16

“Are there substances that are repelled by water?”
You are probably familiar with water. I mean, it’s the basic principle of all life on this planet! And this importance derives from the fact that water can form bonds with nearly all sets of compounds. However, are there substances that are not only insoluble by water but actively repel it? Well, let’s think about how such a substance could exist. The first thing we should analyze is what makes water so bondable, and that comes as a consequence of the polar nature it’s structure. So logically speaking, shouldn’t nonpolar elements have difficulty bonding with water? This is the operating principle behind hydrophobic substances. Examples of hyrophobic molecules include alkanes, oils, and fats.

Equivalent forces

Equivalent forces

Equivalent forces

09/13/16

“How can we simplify force diagrams?”

 

When working in physics or engineering, we all have to work with forces. Sometimes, we will have a multitude of forces, all going in different direction. However, how could we simplify all of these different elements of a problem to get the big picture and streamline our solution process? Well, let’s think about it. First we should think of our objective, and that is to see what happens when all of these forces are combined. So how about we take the components of each of the separate forces and moments, add them together, and find the equivalent force for all of these values? For example, let’s suppose that we had a bar of length 6 meters, with one force of 20 acting on the far left from the top and another one of 20 newtons acting at the far right coming in from the bottom. When we do all of the calculations, the equivalent force in the x direction will be 0 Newtons (Since none of the forces have an x component), The net force in the y direction will be 0 Newtons (since both forces are going in opposite directions, they will subtract each other) and the net moment will be 135 N-m (Since they are both in the same moment direction, 3m*20N+3m*25N=135N-m). With the use of equivalent forces, we can analyze an unlimited amount of problems, ranging from structural engineering to electrodynamics

Circumstellar habitable zone

Circumstellar habitable zone

Circumstellar habitable zone

Isaac Gendler

 

“What is the area around a sun in which a planet can sustain life?”

Ever since humanity first looked to the stars, we have dreamed about inhabiting other worlds. But to our dismay, ever since the beginning of surface readings of the other planets inhabiting our solar system, we have found that the sufficient conditions for complex life are truly rare indeed. However, with the recent and exponential discovery of exoplanets, this dream might become a possibility again. And one of the first steps we must take is to find at what range around a star can a planet support life. To solve this question, we must think about what is the primary source of complex life. After much debate, scientists have decided that liquid water is such as source. So for a planet to be habitable, it must be far enough from the sun to not have it’s water boil up, but not far enough to have it’s reservoirs freeze up either. The range is represented as a torus around the sun, and the size is contingent on how much energy a sun gives off, so if a sun gives off only a small amount of energy, it’s radius will be smaller, and if it gives off a lot, it’s radius will be higher. Astronomers and astrophysicists have termed this phenomena the circumstellar habitable zone. Given the right amount of atmospheric pressure and range from the sun, liquid water is possible for life on another plant.

Proxima B

Proxima B

Proxima B

09/10/16

“Is one of our nearest rocky planet habitable?”

 

A discovery has been made that is possibly so great that it can change the course of humanity forever. Or not. A new planet has been discovered in Proxima centauri (the nearest solar system to ours) only 4.2 light years away from us called Proxima B. We already know a few things about Proxima B, specifically has a mass that is just over a third greater than the Earth’s, it is only slightly more than seven million kilometers away from the star that it orbits, and is tidally locked (meaning one face of the planet will always be facing the star). But more importantly, this planet falls within the habitable zone of it’s star, which means that this planet has temperatures in the range  that is “just right” to host liquid water.

However, there are many factors of this planet that might just burst our bubble. First of all, we have no idea what the atmosphere of proxima B is composed of. In fact, for all we know, it could be completely toxic! Also, since the host star of Proxima B is a red dwarf, the habitable zone for the distance for the habitable zone of this planet is merely 5% of our own. This means that Proxima B is extremely close to it’s orbiting sun. So close in fact that the time for a single year to go by is merely 11 Earth days, and since red dwarfs can be very volatile, there is a strong possibility of unpredictable flairs from the planet.

Proxima B is a perfect example of why as a scientific thinker one must express excitement yet restraint when hearing possibly paradigm shifting news, since we must not bee to short-sighted to observe that such news could be false, yet not too cynical to take joy in the wonder and mystery of the universe.

Pulleys and mechanical advantage

Pulleys and mechanical advantage

Pulleys and mechanical advantage

09/06/16

“Is it possible to lift an object with a force that’s less than it’s weight?”

 

If you ever had to design a system focused on lifting objects, you probably bemoan the fact that if you want to lift a heavy object, you have to use a force that is greater or equal to it’s weight.

Or do you have to?

What if there was some way if we could manipulate the laws of physics, so we could lift an object with a force that is less than it’s weight? Well, let’s think about how we could do this using mechanical advantage.

Let us start with a very simple machine called a pulley. More specifically, we will be starting with a single, fixed pulley. A fixed pulley is a dimply a disk hinged onto an axis in which it is free to revolve around but may not move transitionally. If we were to take a rope and move throw it over the circumference of a pulley, it would reverse the direction of the rope, so we could lift an object while using a downward force instead of an upward force. We still have to use the same force as the weight, but it allows us to change directions.

Now let’s go a step further. What if we were to take that same rope, and make it go under a new pulley, this time a moveable pulley, attach the end of the rope to a ceiling like structure above the pulley, and attach the weight to the moveable pulley. Now the rope will be supporting the pulley on both sides of the object, it can effectively double it’s force value! This means we can now use a force value that is less than the weight of our object to lift it up! You can even create more complex pulley systems to create a greater mechanical advantage. However, there is one major downside to using this setup. Since energy must be conserved, and you are using a smaller force, you must increase the distance you pull your object proportionally to the strength of the force you are using. For example, if you have use a force that is half of the weight, then you will have to pull the rope twice as far, three times as far for a force a third of the weight, and so on. In addition, when we perform these calculations, we assume a massless pulley with no moment of inertia or friction, so there are bound to be some inefficiencies that will require us to use even greater distances

All in all, pulley systems are a testaments of human ingenuity, and are a classical representation of simple yet effective engineering.  

Blood pressure

Blood pressure

Blood pressure

09/05/16

“What is blood pressure?”

When you go for a medical checkup, you will often hear a lot of talk about your “blood pressure”. But what exactly is this phenomena? Well, believe it or not, blood pressure is  actually a very simple concept. Your body is able to maintain it’s operations because the heart pumps blood (which carries oxygen) to all of it’s vital systems. This pumping motion causes blood to be pushed against the walls of your blood vessels, and we can quantify this force as blood pressure. Your blood pressure is usually measured in “millimeters of mercury” (or mmHg), and is given two values (for example, a stable blood pressure is considered to be 120/80 mmHg). But why on Earth will your blood pressure be given two values? Well, let’s think about it. When your heart pumps blood, it does not do so in a constant fashion. Instead, it acts like a piston, with a force changing in a beating nature. So your blood pressure will be the highest at the peak force (termed the systolic blood pressure), and lowest at the bottom (termed the diastolic blood pressure). The higher your blood pressure is, the higher you will have a risk of developing heart heart problems. For example, someone with a blood pressure reading of 135/85 mmHg is twice as likely to receive a heart attack as someone with a blood pressure of 115/75

Galvanic cells

Galvanic cells

Galvanic cells

08/27/16

“What is the simplest possible battery?”

 

Batteries are some of the most omnipresent electrical components in human civilization. However, what is the most simple form of them? Well, in order to do that, we have to put everything into it’s most basic parts.

Well, let’s suppose we have a slab of zinc and a slab of copper, both occupying space in separate dishes of water. Both of them have some of their substance dissolved in the water. The electrons on the zinc solvent want to leave the element, while the copper solvent (with a charge of +2) wants to obtain electrons. If we connect both the copper and the zinc slab with a conducting wire, then the extra electrons on the zinc side will sense the voltage potential on the other side, creating a current, with the zinc side being the cathode and the copper side being the anode. The zinc increasingly becomes oxidized, while the copper becomes increasingly redoxed. However, as this process progresses, more zinc cations will be generated along with the disappearance of more anions, leading to a short life time!. To solve this problem, a salt bridge is instituted connecting the zinc and lead sides. This salt bridge is made up of Potassium Chloride [KCl] in a pseudo-aqueous solution (meaning that it is viscous to a point that the salt will not immediately react with the surrounding elements). As the process goes on and both sides become more charge neutral, the salt will break up bit by bit to have the positive potassium ions replenish the charge of the copper and the negative chloride will replenish the charge of the zinc

 

This in turn creates a simple battery, called a galvanic cell (Also termed a voltaic cell, after the Two Italian scientists Luigi Galvani and Alessandro Volta, respectively).