Author: Isaac Gendler

Yield

Yield

08/29/16

“How can we measure when a deformation will be permanent on a material?”

When you were young, you probably noticed that if you apply enough stress onto an object, there will be a point in which in the material will be permanently deformed. However, did you ever consider that we might be able to classify this point in some form? Well, after many years of research, structural engineers have termed this “point of no return” as the yield. In technical terms, the yield point or yield strength is a material property that measures the point at which the level of stress applied becomes so high that the material will no longer deform elastically (meaning returning to it’s original shape) and instead deform plastically (meaning that there is some permanent deformation). The yield strength of an object is very important for estimating the applied strength it can take, since it could be used for pre-emptive failure analysis.

Trusses

Trusses

08/28/16

“What is the fundamental framework behind many modern structures?”

Have you ever wondered what exactly makes moderns structures such as bridges and houses supportable? Well, believe it or not, all of these complex structures have their foundations in a straightforward yet ingenious engineering piece, the beam. And not just beams by themselves, but beams arranged in a very particular way. When making edifices, one must take into account that beams have very little lateral strength. In other words, beams do not have much strength to support perpendicular forces. However, beams are very sturdy when it comes to compressive and tensile forces. So in order to build complex structures, beams must be construed in a way that all of the forces are applied at the joints so that all of the forces are either compressive or tensile forces. We can accomplish this by having the beams must be connected only by their joints. This way, all of the loads will be distributed on the ends of the beam, so we can have highly stable structures without having to worry about collapse. This type of framework is called a truss, and is used in all forms of engineering.

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).

Hydropower

Hydropower

08/26/16

“Can water be used to create useful energy?”

Water is one of the most omnipresent substances found on this planet.An entire three-quarters of the planet is covered by it. Water often moves not in small streams but with large flows, piling through it’s path with titanic levels of energy. So one might think, is it possible to capture some of this energy to transfer it into useful forms?

Well, let’s think about how we could do so. First of all, we know that turbines can extract energy from moving fluids to power a generator to create electricity. Second of all, We know that water flow can be controlled through the uses of dams. So what if we placed a damn near a flowing path of water, and directed all of that energy so it would move a turbine that would power human infrastructure? Well, this is the operating principle behind hydropower.

Hydropower is the use of the kinetic energy of water to power electricity. The power generated by a hydropower plant can be calculated with the following equation P=Mu*rho*Q*g*h, with Mu being the efficiency of the turbines, rho being the density of the water passing through, (Kilograms per cubic meter), Q being the flow (Cubic meters per second), g being the acceleration by gravity, and h being the height difference between the inlet and outlet in meters. Hydropower is clean, renewable, and affordable form of energy. Hydropower produces almost one fifth of the world’s electricity, the primary contributors being China, Canada, Brazil, The United States, and Russia. Notable hydroelectric projects include the three gorges damn in China and the Grand Coulee Dam on the Columbia River in northern Washington in the U.S. However, one has to be cautious when developing such systems, and the infrastructure may disrupt local wildlife and natural resources.

In summation, hydropower is a fascinating subject, and engineers around the world are dedicating themselves to the study and application of this form of power.

Cell theory

Cell theory

08/25/16

“What is the fundamental part of biological organisms?”

Have you ever wondered what is the most fundamental part of biological organisms? Well, believe it or not, all living beings are primarily composed of a form of matter called cells. Cells are defined as the simplest form of living matter. There are two types of cells, eukaryotic and prokaryotic cells . Eukaryotic cells contain a true nucleus (which houses DNA), and is contained in cell membrane to isolate itself from other cells. Prokaryotic cells are different from eukaryotic cells because instead of having the DNA isolated in a protective membrane, it is wrapped up in a region called the nucleoid. Complex life such as plants, animals, fungi, and protists are composed of eukaryotic cells, while simpler life is composed of prokaryotic cells.

Why does soda fizz?

Why does soda fizz?

08/24/16

“Why does soda fizz?”

Have you ever opened a can of soda and just wondered why it seemed to fizz? Well, believe it or not, it all comes down to one very simple scientific principle, pressure. When soft-drink manufacturers construct soda, they force Carbon dioxide [CO2] into water [H2O] at over 8.274 kilopascals. This pressure will be sustained inside an insulating material such as a soda can, and by result the carbon dioxide will stay dissolved in the water. However, if one were to open this can, then all of the carbon dioxide will be liberated from the soda can because of the pressure difference, causing fizz to form!

Smart rubber

Smart rubber

08/23/16

“Are there materials that can “heal” themselves when torn?”

Have you ever had the misfortune of having a rubber material rendered useless just because you’ve torn it? Wouldn’t it be nice to have some form of rubber in which the object can heal itself once it becomes damaged?

Well, how about instead of being in dismay over such an issue, we take action and use our technical mind to solve the problems! First of all, let’s think of the root cause. Rubber materials obtain their strength from the fact that they are composed of multiple polymer molecules being crosslinked through three different ways: Covalent, ionic, and hydrogen bonding. However, only hydrogen bonding can revert to it’s original structure after being deformed. So wouldn’t it be logical that if we only had the rubber composed of hydrogen bonds, then it would be completely mendable?

Well, this is exactly the working principle behind smart rubber. Smart rubber is rubber composed entirely of hydrogen bonds, so that it “heal” itself when necessary (at near room temperature). Smart rubber can be used to create items such as shoes and tires that can repair themselves after intense use. Smart rubber is better for the environment since it encourages less waste. The one downside of Smart rubber is that it is weaker than normal rubber by nature, as the material lacks the extra structure of the covalent and ionic bonds.

Hydrogen bonding

Hydrogen bonding

08/22/16

“Why is water such a special element?”

Water is a very special element. This single molecule allows for the scientific miracle of life to occur, whether it be the smallest of fungi to the largest of whales. Water allows for humans to hydrate themselves, and to create agriculture.

But why is it so special? Well, believe it or not, it all comes down to one basic property of water, the special way that it bonds. Water is made up of one oxygen atom and two hydrogen atoms (hence the name H2O). Both of these atoms have shared electrons. However, due to the electronegativity of the oxygen atom, the electrons will be closer to the oxygen than the hydrogen atom. This means that the water molecule will become polarized, resulting in a dipole. This type of charge is so special that scientists and engineers have termed this type of bond a hydrogen bond.

Because of this asymmetry of charge, water can dissolve electrolytes such as sodium chloride [NaCl] easily. This hydrogen bond also allows water to hold together DNA, proteins, and other macromolecules. The polar quality of hydrogen molecules also allows for other water molecules to attract one another very easily, with the oxygens reaching out to the hydrogens. This form of bonding gives water some of it’s special properties, such as a high boiling point (100 degrees C) and surface tension.

Motor armatures

Motor armatures

08/21/16

“What component causes an electric motor to spin?”

We know that Electric motors have two main mechanical parts, a stationary stator that encapsulates a rotating rotor. Now, how is this rotation induced? Well, in addition to having the aforementioned two mechanical components, electric motors has two electrical components. The first electrical component is called the field, which is simply the magnetic field component inside the airgap. This field will turn the armature, which is the primary power producing component in the motor. The armature carries current that is oriented perpendicular to the magnetic field, which in turn will induce a force which will cause a torque to take place. The armature usually consist of several conductive windings for this effect to happen. The field and the armature can be on either on the rotor or the stator but one must only occupy one other.