“Can biological organisms resist electric current?”
Biological organisms have many properties. It turns out they also have some electrical resistance as well! This phenomenon is known as bioelectrical resistance and is usually caused by the exterior epidermis of organisms.
“Can fuel exist in a solid form?”
When we think of fuel, we often think of the liquid petroleum that exists within our car. However, not all fuel has to be in a fluid form. In fact, there is such a thing as solid fuels to create heat and power. Many of these solid fuels are very well known such as coal, plant biomass, charcoal, wood, and even municipal waste!
“How can we keep a building’s air fresh?”
Buildings are great for enclosing an interior space. However, if there is no contact with the outside, then the air inside will become trapped and polluted. So how can we make sure that fresh air is continually supplied without overcooling the building? Well, we can use something known as ventilation, that allows some air to pass in and some to pass out, creating a continuous cycling of air. Ventilation is a fundamental part of the built environment and has become of the most important standards.
The Physics of a Hanukkah Dreidel
“How does a Hanukkah dreidel spin?”
Hanukkah dreidels are great fun for people of all ages. These little tops are able to spin round and round with a very peculiar pattern. However, why exactly do they spin? Well, let’s use our scientific mindset to find out. All spinning objects with mass have a property called angular momentum. The more moment of inertia it has and the greater spin then the greater angular momentum it will have. Angular momentum tries to be conserved so a dreidel will try to keep on spinning when acting upon!
Happy Hanukkah, and Happy Holidays to everybody!!!
Entropy Changes of an Ideal Gas
“How does the entropy of an ideal gas change with time?”
When an ideal gas undergoes a nonadiabatic process, it’s entropy is bound to change. However, how can we quantify such a change? Well, let’s use our engineering mindset to figure this out. One way would be to look at a thermodynamic property table, find the specific enthalpies for different temperatures, and then take the difference in values. Another way would be to plug in the equation delta s = C_v*ln(t2/t1) + R*ln(v2/v1) or delta s = C_p*ln(t2/t1) – R*ln(p2/p1).
“How do metals waste away with time?”
Metals are some of the most widely used materials in the world. However, nothing within the realm of physics lasts forever. If a metal is immersed in an atmosphere, then it will be surrounded by chemicals alien to its own. Chemical reactions are bound to occur, and over time this metal will decay and waste away in a process known as corrosion. Corrosion is a very important engineering factor, especially for public infrastructure. So much so that in 1998 alone the total annual direct cost of corrosion in the U.S. was around. $276 billion!
The Dew Point
“How can we measure the point in which saturation occurs?”
When it gets humid outside, it’s very easy for moisture to appear on surfaces. However, why does that happen? Well, the answer lies in a most interesting property called the Dew Point. The dew point is the temperature at which the gas in a given area will condense into a liquid. If an object cooler than this point comes in contact with air, then it is possible for dew to form. HVAC system engineers must keep this value in mind when designing dehumidifier equipment.