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leahmaew

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  1. leahmaew
    Every time theres a huge storm its hard to keep our eyes off the pounding rain on the pavement, or dark clouds or the lightning that zaps out of the sky to the ground and is gone in a moments notice. The sudden flash of light isn't just to scare children or puppies though, its actually an act of nature and physics, believe it or not. Lightning is based off of the physics of electromagnestim, which is the science of the interactions between charges, electric fields and electric currents. Lightning is caused by the build up of electrostatic charge in clouds. Within this electrostatic build up, one part of the cloud builds up with positive charge while the other part of the cloud builds up with negative charge, this causes a large separation of charge within the cloud. When this separation of charges within the cloud becomes big enough this may lead to the negative charges leaping to the positive charges of another cloud. When this happens, sheet lightning occurs. What we usually see out our bedroom windows during a storm is when lightning strikes the ground.


    There are a few different types of lightning, the lightning previously referred to (from cloud to ground),the ground acts as a pool of electrical charge, and when the clouds gain charge, the ground attempts to balance out the charge by gathering the opposite charge beneath the cloud system. When the difference between charges becomes great enough that leads to a breakdown of air between the charges. When this break down occurs that is when lightning occurs and it either occurs from cloud to cloud or from ground to cloud. What usually happens is the lightning starts at the ground and flows upward, it happens vice versa too, however it usually begins at the ground. To go into further depth, when a pool of negative charges are collected at the bottom of the cloud, that forces the negative charges on the ground to be pushed away. When this happens, that leave the charge of the ground positive. So usually a stream of negative charge travels down to the postively charged ground, when this occurs a stream of positive charges comes up from the ground because the two opposite charges attract. When the streams of charge come in contact with each other they create a very conductive path which allows a sudden down surge of electrons to jump to the ground. This is the lightning.

    The whole reason for the lightning is because of the basic electromagnetic principal that opposite charges attract. The reason that opposite charges attract is so that they can reach an equilibrium. Two oppositely charged objects want to be close enough so that they can discharge and become neutral or reach equilibrium. The different charges are due to the amount of electrons or protons in an atmosphere, electrons have a negative charge of 1.6 x 10 to the negative 19th coulombs, enough electrons and the charge in the atmosphere (in this case cloud) is negative so a deficit of electrons creates a positive net charge. To explain the breakdown of air that creates lightning, ionization will have to explained. When two opposite charges are separated and cannot exchange electrons through contact, they must exchange electrons through a medium. In the case of electric storms, the air becomes the medium for this exchange. However air is not conductive, so this means that electrons cannot pass through it easily, for this problem to be changed the process of ionization must occur. This occurs when when a large amount of charged particles try passing through the medium this then causes the electrons and protons of the medium to separate, when that happens it creates a path between the two regions, and then the charges can flow.

    Lightning as you can see is a very fascinating topic! Charges are all around us even when we can't see their effects, so its cool to be able to actually SEE the results that charges have in our world and in our atmosphere!






  2. leahmaew
    With The Amazing SpiderMan being filmed in the city of Rochester, I'm sure a lot of people are curious: how does he do it?! How strong does spidermans web need to be? How much force does it need for Spiderman to be a successful superhero? Is it likely that if we were about to fall off a cliff Spiderman could catch us with his web and save us just in time? What about if we were about to drive off a cliff in a car? What about a train? Spiderman has to have some pretty amazing talents to be able to save the day, but we don't know if its actually realistic. It would sure be nice to know that if my Honda Odysey "Oliver" was falling off a cliff that Spiderman would be able to save me before I flew off the cliff and right into a lake, sinking to the bottom to my doom. The question we're going to answer is how much force spiderman would need to be able to save my car. Lets have a look.

    Approximately Olivers mass is 2730 kilograms, and I was late to work that day so suppose Oliver is speeding a little and I'm traveling down the road at 20 meters per second when all of a sudden a cliff appears out of nowhere and I'm about to plummet to my death. The distance from my van to the cliff is 50 meters. And we know the acceleration on earth due to gravity is 9.81 meters/second squared. How long would it take before I fell off the cliff? Well lets see:

    Velocity initial = 20 m/s
    Velocity final = ?
    Acceleration = 9.81 m/s(2)
    Distance = 50 m
    Time = ?
    Mass = 2730 kg

    To figure out how long it would take me to fall of the cliff we could use the equation V= D/T. So the velocity, (20 m/s) is equal to the Distance (50 m) over the time. To figure out the time the equation can be rearranged to T = D/V. After plugging everything in, (50 m)/ (20 m/s) is equal to 2.5 seconds. Spiderman only has 2.5 seconds to save me before my van takes the leap of faith. To figure out how much force Oliver is exerting moving towards the clif, you would use the equation, Force = Mass x Acceleration. So the Force Oliver is exerting would be 262724 Newtons. For Spiderman to exert the same or a greater force, or for him to stop my car or pull it away from the cliff, he would need to be accelerating the opposite way to have a greater Force since his mass if much less than Oliver. Lets assume Spiderman is around 72.0 kg, (he's not one of the bulkier superheros). And his Force needs to be equal to 262724 Newtons.

    F = MA > (262724 Newtons) = (72.0 kg)(A) > (262724 N) / (72.0 kg) = A >

    Spiderman would need to be accelerating the opposite direction at 3648.9 meters/second squared.

    Hmmmm now thats pretty fast. Us mere humans would probably never be able to pull a stunt like this but I'm sure
    Spiderman could. Just incase you're ever driving down the street with the same speed as Oliver in a car of a similar weight, just keep in mind when Spiderman comes down to save you, that he's working pretty hard.

  3. leahmaew
    A lot of people wouldn't know that singing actually involves a great deal of physics, for example the carrying of sound from a singer to the listener, has to do with mechanical waves. Different people have different types of voices for singing, the most common difference in peoples singing voices is their range of voice. Voice ranges can reach very high notes, or they can reach very low notes. A good singer is most likely able to hit very low notes as well as very high notes. The pitch, or the high or lowness that someone can sing, is associated with frequencey.

    Sound is a mechanical wave because it requires a medium to travel, when someone sings, the higher frequency they sing in, the higher their pitch will be, for example, someone with a squeaky voice like Taylor Swift sings at a high frequencey, while someone with a low raspy voice like Adele sings at a lower frequency. Frequency is measured in hertz and the frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium. Frequency is measured as the number of wave cycles that occur in one second. 1 hertz = 1 vibration/second





    Amplitude of a sound wave is also part of singing. When someone sings with a greater amplitude compared to a smaller amplitude, they are singing louder compared to singing quieter. Amplitude is the size of the vibration in a sound wave that affects how loud we sing. Larger vibrations make a louder sound.



    Diffraction is also used in singing because it helps us to explain why sound can be heard from different rooms when someone is singing. Diffraction uses the edges of barriers to send sound waves out in a different direction than they were origonally going. For example if someone was performing a solo in a highschool auditorium and someone opened the doors, now most likely the whole hallway would be able to hear them. That is because with long wavelengths and small openings, sound diffractions more and therefore will be sent out further. Singing involves a lot of physics and without understanding how sound waves travel or how to magnify voices then one would not be able to master the art of singing.

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