Tuesday, August 11, 2009

sorry folks

I was in a car accident on friday, I should be posting daily again next monday. Thanks

Tuesday, August 4, 2009

Alzheimer's Disease

Today's subject is one that is unfortunately close my heart. Just about everyone I know has a family member suffering from this disease and I am no exception. My grandma is entering the middle stages of Alzheimer's and I cannot just sit back and watch. Since doing nothing is not an option I've signed up for an Alzheimer's walk in not just her honor but for everyone who's family is being hurt by this painful disease. If anyone reading out there would like to donate to this cause just follow this link and you'll be directed to the foundation's secure website. http://ErieCountyWalk.kintera.org/jenniferleib

Alzheimer's disease is an incurable, degenerative, terminal disease first described in 1906 by Dr. Alois Alzheimer. The earliest observable symptoms are stress and memory loss. Memory loss is often mild at first, usually forgetting recently learned things. More advanced symptoms include confusion, aggression, withdrawal, and mood swings as well as long-term memory loss.

Signs of alzheimer's can appear years before an official alzheimer's diagnosis, these signs are memory loss in the form of decreased ability to absorb new information along with a sense of apathy. As things progress to an official diagnosis, memory loss becomes more apparent and problems with language and movement occur. At this stage it is mostly newer memories that are impaired by the disease. Fine motor skills are also affected, making the patient clumsy.

The moderate stage of alzheimer's disease make it difficult for the patient to live on their own. They begin losing their vocabulary, this causes frequent incorrect word substitutions as reading and writing skills are lost. The patient may no long recognize their close family members and lose the ability to perform complex tasks. Their long term memory begins to fade and behavioral changes become more apparent. Mood swings such as agression or crying begin to occur.

In the final stages of alzheimer's disease the patient is completely dependant. They lose most of their speech and sometimes all language. Most patients display apathy instead of aggression as with the less advanced stages. Eventually the patient cannot take care of themselves at all and either the brain loses control of basic function or they pass away because of other diseases due to a weakened immune system.

Saturday, August 1, 2009

Pseudoscience Saturday! - Phrenology

I've decided that every saturday I'm going to talk about some silly old pseudoscience and if I have time during the day put up a regular post too. Today's post is about phrenology, the study of skull shape.

Phrenology all started in 1796 with a scientist named Franz Gall, phrenology remained in the realm of real science all the way until the 1900s. Phrenology is based on the concept that the mind has localized areas that do specific things, these areas are also called modules. Phrenologists believe that the size of the modules showed different aspects of a person's personality. The reason they believed this is that it was assumed that the importance a person gave to each specific module made it larger or smaller. Under these beliefs it was possible to map out a person's personality by measuring different areas of their skull. Gall believed that there were 27 specific modules in the brain and during a screening the phrenologist would feel a person's skull to map out and measure all 27 modules. Back in it's prime, phrenology was used to predict the future lives of children, screen potential job applicants and size up potential marriage partners.

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.