Friday, July 31, 2009

Why do people get itchy?

Unfortunately, this one doesn't really have a personal or entertaining background. I was just curious.

Itching is a reaction that helps protect our skin, or at least that is its' intention. There are two different kinds of itches and both are transmitted the same way, through nerves, up the spinal cord and into the brain.

The first type of itch is one caused by contact; these itches happen because the body is trying to warn that what touched the skin might be dangerous. The body sends signals to make the skin itchy in the hopes that whatever touched it will be scratched off and won't cause damage.

The second type of itch is caused by bug bites, allergies, or anything that causes the body to release a chemical called histamine. These itches are an attempt to get the top layer of dead skin and any foreign material scratched off of the irritated area.

Thursday, July 30, 2009

Phlogiston - proof that science isn't always right

Before I start this I'd like to say this theory has been disproven, phlogiston is not real. Phlogiston is an old theory used to explain heat back in the 1600s and has been disproved. This is more of a little history lesson then anything and I just think it's a funny little theory.

The theory of phlogiston started in 1667 with a scientist named Johann Becher. Phlogiston is an attempt to explain heat. It was believed that phlogiston was an element that existed inside of anything that can burn or elplode (aka combustible bodies). When these combustible bodies did explode the phlogiston was released into the air. Substances with phlogiston in them were refered to as "phlogisticated" and then "deplogisticated" when burned. Testing the theory of phlogiston in enclosed spaces soon revealed that combustion would not last long in closed areas. This led scientists to believe the air had the ability to absorb only a finite amount of phlogiston. Once the phlogiston limit was reached the air could not support life or combustion. Since air filled with phlogiston could not support life it was believed that respiration existed to remove phlogiston from the body. Therefore phlogiston was believed to be anti-oxygen. In 1753 experiments revealed problems with the phlogiston theory. Some metals gained mass after being burned even though they lost phlogiston. Some scientists concluded that phlogiston had negative mass while others tried to explain that it is simple lighter then air. Unfortunately neither of these explinations really covered things and the phlogiston theory was eventually replaced with the oxygen theory that is accepted today.

Wednesday, July 29, 2009

How do air conditioners work?

As I was sitting in my 15 year old car with a broken AC on the way home from work yesterday I decided this would be a good idea. I am only going to explain evaporative coolers in this post, there is another type called an absorption chiller but it is more complicated and although I understand it I am still trying to figure out how I'd like to explain in here in stuff I don't understand.

Evaporative Coolers -

Evaporative coolers draw outside air in and pass the air through a wet pad such as a water soaked sponge. In doing this some of the sensible heat is converted to latent heat by evaporation of water of of the wet pad. Although the total heat (sensible heat + latent heat) remains unchanged if the entering air is dry enough it can have substantial effects.

Sensible Heat - Potential energy in the form of thermal energy (heat). It is heat that is added or removed from air without a change in water vapor content.

Latent Heat - The amount of energy released or absorbed during a change of state or phase transition.

Phase Transition - The transition of a substance from soild, liquid, gas or plasma to another phase of matter.

Tuesday, July 28, 2009

how do headphone drivers work?

As an audiophile I thought this could be a fun one

Dynamic Drivers -

Also known as moving coil drivers, these headphones use a static magnetic field and a moving diaphragm to create sound. Inside is a stationary magnetic element surrounded by a light weight, stiff diaphragm used to create the sound waves. The diaphragm is attached to a coil of wire which allows a current to create the alternating magnetic field required to move the diaphragm up and down along the stationary magnet to create sound waves.

Unfortunately I could not find the picture I wanted to use to explain these drivers. Back in high school I had an amazing engineering teacher and when I recently went to visit him on his desk he had a dynamic speaker made out of a paper bowl, some wire, magnets and k'nex. This speaker was the most simple example of a dynamic driver I've seen and if I can get back to his office before I need to go back to school I'll replace this picture with the one I'd really like to put here.

Balanced Armature Drivers -

These drivers are much smaller then dynamic drivers can be. Although these drivers are unstable, they provide more sound using the less power then any other type of driver can. These drivers have a moving magnetic armature that is position in a way that allows them to move in the magnetic field of the permanent magnet that surrounds them while being perfectly balanced when not moving, hence the name.

When a current is run though these drivers it causes the armature to twist one way or the other, tugging or pulling on the diaphragm, this diaphragm manipulation creates the sound.

Monday, July 27, 2009

What causes lightning and thunder?

This was suggested by a co-worker of mine and since I did tornadoes I thought it could be fun to explore some more interesting weather.

Lightning -

According to the electrostatic induction hypothesis, charges are driven apart resulting in lightning. As strong updraft winds carry water through clouds it super cools the molecules to between -10 degrees celsius and - 20 degrees celsius. As this water collides with ice crystals in the clouds it creates a water-ice micture called graupel. The collisions causea slight positive charge to transfer to the ice crystals and a slight negative charge to transfer to the graupel. Ice crystals are lighter then graupel so the wind blows them to the top of the cloud. This causes the top of the cloud to be positively charged while the bottom is negativeluy charged by the graupel. Charge seperation and accumulation continues until the electical potential is so great that is results in lightning.

Thunder -

Thunder is simply a shock wave caused by lightning. Lightning heats up the air to aproximately 50,000 degrees farenheit. This rapid heating causes the air to expand at speeds faster then the sound can travel through surrounding cooler air, resulting in a shockwave not unlike those caused by explosions.

Sunday, July 26, 2009

How do tornadoes form?

I'm typing this while my mom makes a failing attempt to convince my brother, dad and myself that we're going to get killed by a giant tornado unless we all pile into the basement with her and our dog. I've lived on Long Island my whole life and we've never had a tornado warning before this that I can remember. I am personally not too concerned which is why I'm not in the basement with my mom. Anyway all this got me thinking, how do they form?

A tornado is a column of air that is rotating very quickly, this column extends from a cloud (usually a thunderstorm cloud) to the ground. Most tornados have winds under 100 mph but some can be over 250 mph.

It takes several conditions to form not only a tornado but the thunderstorm clouds they form from. A lot of low level moisture is required and a catalyst that pushes that moisture up into the air, usually this catalyst is something like cold winds. This moisture rising and getting saturated as it rises results in a very tall distinctly shaped cloud when the atmosphere is unstable.

In order for the tornado to form there needs to be a strong, low, wind that rotates horizontally to the ground. The rising air in the thunderstorm cloud will pick up the horizontal wind, rotating it from horizontal to vertical creating the column of air from the cloud to the ground known as a tornado.

Unstable Atmosphere - An unstable atmosphere is one where the temperature decreases rapidly with hight.

why is the sky and ocean blue?

I recently went on a 9 day cruise to the Caribbean. Nine days is a long time to be surrounded by water. My family and I spent a lot of time on the back of the boat watching the propellers churn up beautiful pale blue water and left me thinking about why it's blue.  I also decided to find out why the sky is blue because well... why not? 

Lets start with the ocean - 

The ocean is blue because the water absorbs the colors in the red end of the light spectrum. Since everything else is absorbed all we see is blue. 
*The ocean can also appear green or red as light bounces off of floating sediment in the water. 

The sky -

Blue sky is the result of rayleigh scattering. As light passes through the atmosphere, longer wave lengths pass through unaffected. Shorter wave lengths are absorbed by gas molecules and the light is radiated in all directions. Since this rayleigh scattering is happening all over the sky, what you see is a blue sky. 

Saturday, July 25, 2009

What happens to a human body in a vacuum?

The whole concept for this blog all started on a forum in a thread about the original moon landing. I realized that I have no true understanding of how it happened and that bothered me a lot. It made me feel pretty dumb and simple for not understanding the science behind the technology that humans have used to explore space. I've been looking for a good book about the technology but I haven't found one yet. It doesn't have to be simple or anything like that, I love doing research, I'll just have to keep looking.

So my first question - what happens to a human body in a vacuum. 

A human in a vacuum will lose consciousness after a few seconds and die of hypoxia within a few minutes. Blood and other bodily fluids will boil (a condition known as ebullism) the body may swell up to two times it's normal size. Rapid evaporative cooling of the skin will create frost, particularly in the mouth. 

Hypoxia - a condition where the body (generalized hypoxia) or a region of the body (tissue hypoxia) is deprived of adequate oxygen.

Ebullism - The formation of gas bubbles in bodily fluids due to reduced environmental pressure.

Well this is new

My name is Jen and there are a lot of things in this world that I don't understand yet. A little about myself - I am currently a sophomore at the University At Buffalo and my intended major is biomedical studies, I intend to go into a career in medicine. I like video games, I'm an audiophile and I love science, I'm also a photographer when I have the time. I decided to make this blog because there are a lot of things I feel like I should know about that I just never bothered to learn. Little things like why light bulbs work, what happens when you put a person in a vacuum, why is the sky blue? I've decided to start carrying around a notebook and writing down questions as they come to me and answering them as I find the time. Since I'm always on the computer I thought it would be a good idea to also put it online. 

If you found this randomly I hope you find what you're looking for!