Author: Isaac Gendler

Thermosetting polymers

Thermosetting polymers

05/16/17

“Can certain plastics become harder with heat?”
Thermoplastic materials are widely used for their behavioral effects to induced heat. However, is it possible that some materials might become harder with temperature in an irreversible process? Well, let’s use our scientific mindset to find out. We know that when polymers become cross-linked, they become harder and tougher. So it would follow that when heated, they would be stronger when compared to a non-cross-linked material. What more, because these polymer chains are bonded to each other, they will not change shape after reheating! Thermosetting polymers have applications to be found everywhere, from latex gloves to erasers to bicycle tires.

What happens when two lenses are placed together?

What happens when two lenses are placed together?

05/15/17

“How do we solve a physics problem with two lenses placed together?”
When doing a geometric optics problems, we often assume the lenses to be discrete from one another. However, what happens when we have two lenses right next to each other? Well, let’s think about it using our mathematical mindset. If we look carefully, then we will notice that the same amount of light will be incoming and outgoing for both sides. This is similar to how the voltage drop on two parallel resistors is the same. So what if we were to treat our optical system in a similar manner? Well, after much research into this matter, opticists have shown that both lenses can be replaced with an equivalent lens with a focal length given by the equation 1/f_combined=1/f1+1/f2.

Concave mirrors

Concave mirrors

05/14/17

“How does a mirror that bends inwards behave?”
Mirrors come in all different shapes and sizes. Some are straight like a piece of paper, some bend outwards, some inwards. However, what are some of the defining physical characteristics of mirrors? Well, let’s analyze it with our scientific mindsets. When an object is beyond the center of curvature, then an image real, inverted, and minimized will be produced. If the object is at the center of curvature, then a real inverted image of equal size will be produced. If the image is between the center length and focal point, then an image real, inverted, and magnified will be produced. If the object is at the focus, then the image will form at – infinity. And if the object is just beyond the focal point, then a magnified virtual image will be formed. Concave mirrors have numerous applications, ranging from the headlights of cars to shaving mirrors and even to visual bomb detectors!

How to calculate change in entropy

How to calculate change in entropy

05/13/17

“How can we calculate the change in entropy for a thermodynamic process?”

It is well known that for all thermodynamic processes, there is a corresponding increase in entropy in the entire system. However, how can we quantitatively measure such a change? Well, after many years of research, physicists and engineers have been able to come up with an equation which states that the change in entropy for a reversible process is equal to the time integral of change of heat divided by the initial temperature, or (delta)s=integral(dq/T). From this, we can derive that for an isothermal expansion or contraction, the equation will be (delta)S=nRln(vf/v0), and (delta)d=-nRln(pf_p0), while in cooling or heating a system it will be (delta)s=ncln(tf/t0) and for a phase transition it will be (delta)s=(delta)h/T.

Volcanic eruptions’ effect on climate change

Volcanic eruptions’ effect on climate change

05/12/17

“How do volcanic eruptions affect climate change?”

Volcanoes are famous for their mighty and breathtaking eruptions. However, many astute individuals are curious about how such phenomena can affect global temperatures. Well, let’s use our scientific mindset to find out. When volcanoes erupt, a multitude of particles is launched from the Earth’s interior and into the atmosphere. Some of these particles are composed of elements such as sulfur dioxide that block the sun’s rays and induce local cooling, while others are made of heat-trapping greenhouse gasses such as carbon dioxide. However, the effects of the latter are quite minuscule in comparison with the former, and if the particles are able to escape into the stratosphere, then a slight drop in temperatures over a large vicinity of the planet will be observed.

Phasors

Phasors

05/11/17

“How can we represent AC current in vector form?”
We have a problem. AC current calculations can be drastically simplified if they are put into vector form. However, at the same time they are constantly changing. So how can we make a dynamic form for phasors? Well, let’s think about it. We know that the magnitude of the combination of the real and imaginary magnitudes of the current will be constant throughout. And we also know that these values of these separately will be constantly oscillating. So what if we were to represent these values with a cosine function and a frequency in order to emulate these properties? Well, these representations are known as phasors and are used for every part of AC circuit analysis.

Batch-collector solar water heater

Batch-collector solar water heater

05/10/17

“How can we use the sun to heat our water?”

Obtaining hot water for a house requires a lot of energy, and it is very well known that the sun emits a large amount of energy, so wouldn’t be logical that we could translate this energy into heated water? Well, as engineers, it’s not enough just to think about a system, we need to implement this system into reality. To start off, we will need a way to hold the water. This can be done with a cylindrical tube. Now, let’s put this tube in a case with a glass roof to allow sunlight to come in and heat the area, a miniature greenhouse so to speak. Next, we will need to fit this tube with inlet and outlet pipes in order to transport the water. For safety precautions, let’s also attach a tempering valve to ensure that the internal temperature does not exceed the operating temperature of the system. It looks like we have just made ourselves what engineers have termed a Batch-collector solar water heater. Batch-collector solar water heaters are a very affordable way to create heated water, but can be very inefficient due to the fact there is no mechanism to ensure long-term heat capacity.

Condensers

Condensers

05/09/17

“How can we make a machine that turns vapor into liquid?”
Liquids such as water are often turned into vapors in machines after thermodynamic processes. However, how can we do the opposite? Well, let’s use our mechanical engineering mindset to figure it out. We know that if we were to have one fluid come in contact with another fluid of a different temperature, then a heat transfer would take place. And if enough heat is transferred, then a phase change will take place. So what if we were to run vapor through a thin pipe surrounded by cooler air, and have this cool air constantly replenished by a fan? Well, eventually our vapor will cool down and condense into a liquid, completing our desired objective. This device is known as a condenser, and can be found in some of our infrastructure’s most important machines ranging from air conditioners to power plants to distillation units!

Landfill Gas to Energy

Landfill Gas to Energy

05/08/17

“How can we convert landfill gas into energy?”

Landfill gas is often left to rot and waste the environment. However, would it be possible if we could actually do something with this corrosive material? Well, let’s use our engineering mindsets to think about this. We know that gasses are transported through piping systems to provide energy. So what is we were to replace these glasses with the methane gasses released by landfills? This system is known as landfill gas to energy and is often used for generating electricity, replacing non-renewable resources, cogeneration, and pipeline gas

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