Electromagnetic Induction

Electromagnetic Induction The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire.Faraday's experiment with induction between coils ...The current in the coil is called an induced current, because the current is brought about (or "induced") by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up. Faraday visualized a magnetic field as composed of many lines of induction, along which a small magnetic compass...

The Chemistry of Love

The Chemistry of Love According to Dr. Helen Fisher, a researcher at Rutgers University, chemistry and love are inextricable. Shes not speaking, though, of the chemistry that makes two people compatible. Instead, shes speaking of the chemicals that are released into our bodies as we experience lust, attraction, and attachment. Chemicals in Each Stage of Love We may think that were using our heads to govern our hearts, but in fact (at least to a degree) were simply responding to the chemicals that help us experience pleasure, excitement, and arousal. Dr. Fisher says there are three stages of love, and each is driven to a degree by a particular set of chemicals.  Ã‚  There is a lot of chemistry involved in feeling attachment, sweaty palms, butterflies in your stomach, etc. Take a look at some of the key biochemical players. Stage 1: Lust If youre feeling eager for a sexual encounter with someone (even if youre not quite sure who youll end up with), chances are youre reacting to the sex hormones testosterone and estrogen. Both of these hormones play an important role in increasing libido in both men and women. Testosterone and estrogen are generated as a result of messages from the hypothalamus of the brain. Testosterone is a very  potent aphrodisiac. Estrogen can make women more libidinous around the time they ovulate (when estrogen levels are at their peak). Stage 2: Attraction Lust is fun, but it may or may not lead to real romance. If you do make it to stage 2 in your relationship, though, chemicals become increasingly important. On the one hand, chemicals associated with attraction can make you feel dreamy. On the other hand, they can make you feel anxious or obsessive. People who are in this early phase of falling in love may even sleep less, or lose their appetite!   Phenylethylamine or PEA: This is a chemical that naturally occurs in the brain and is also found in some foods, such as chocolate. It is a stimulant, much like an amphetamine, that causes the release of norepinephrine and dopamine. This chemical is released when you are falling in love. Its responsible for the head-over-heels, elated part of love.Norepinephrine: When PEA causes this chemical to be released, you feel the effects in the form of sweaty palms and a pounding heart.Dopamine: Dopamine is a neurochemical that appears to be associated with mate selection. An Emory University study found that voles (a type of rodent) chose their mate based on dopamine release. When female voles were injected with dopamine in the presence of a male vole, they could select him from a group of voles later. Stage 3: Attachment Now that youre really committed to someone else, chemicals help you stay connected. Oxytocin: Dopamine triggers the release of oxytocin, which is sometimes called the cuddle hormone. In both genders, oxytocin is released during touching. In women, oxytocin is released during labor and breastfeeding.Serotonin: A chemical that is more prevalent among people with compulsive disorders, serotonin can increase our dependence on another person.Endorphins: Your brain acquires a tolerance to the love stimulants and starts to release endorphins. The honeymoon is over, chemically, around 18 months to 4 years into a relationship. However, this isnt all bad.  Endorphins are associated with feelings  of attachment and comfort. Endorphins are like opiates. They calm anxiety, relieve pain and reduce stress.