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# Elenarohr

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1. ## waves and sound

https://www.youtube.com/watch?feature=player_detailpage&v=EzU79Egl3-c
2. ## shattering glass using sound waves

many people would think that shattering glass is easy. But shattering glass with your voice is a whole different story. The act of shattering a glass with your voice has a huge backround that involves the physics of sound waves. First off, the glass in question needs to be crystal, not just any glass. The glass hums (and doesn't shatter) because the amplitude of the waves is not sufficient to surpass the strength of the glass. in order to break the glass you must porduce a sound that has the same frequency that the glass resonates at the glass should break. In an experiment that myth busters did, it showed that it is very hard to break a glass with just your voice but it is possible. before the glass shatters if you play in in slow mo or up close you can see the glass start to shift like jello. Its surface shakes and eventually (If you have the right tone) will shatter. Its amazing what sound waves can do!!!!!!!!!
3. ## Doppler effect

Every time a firetruck with a siren drives past the school, Mr. Fullerton says "Doppler effect." Although we were learning about what the doppler effect is, i decided to do a little more research on the topic to better my understanding of it. The doppler effect is observed when a wave is moving with respect of the observer. The doppler effect is the result of the movement of waves in which there is an apparent shift in frequency. In a video that we saw in class from a former student, it showed the student in a car with a blowhorn. As she drove past the camera or got closer to it the frequency raised and produced a louder sound. As it gradually moved away the frequecy decreases and the sound gets gradually quieter. Similar to the sound a racecar makes as it passes you on the track at top speed.The doppler effect can be seen in multiple types of waves including water waves, sound waves and even light waves. The doppler effect can even be applied to instruments. How can you play a note on a guitar or piano and have it casually and gradually get softer and softer untill it stops? Doppler effect. If the musician plays the same note while moving toward or away from a stationary listener, the note heard by the listener will indeed change,even if the musician does nothing different.Sound waves are not transverse waves. They are longitudinal waves, created by some type of mechanical vibration that produces a series of compressions and rarefactions in a medium. the Doppler effect is directly related to the frequency of a wave, whether it's made of water, light or sound.
4. ## Why we can't hear in space

As i child i was an eavesdropper. Whenever i wasn't supposed to hear something i would always try and hear it anyways. I tried everything from pressing a glass to the door as well as (when i was desperate) just sticking my ear against the door to hear the latest gossip. Sound is transported by a collision of molecules. On earth we have the medium of air which allows the molecules to collide and form waves. this helps so that we can hear what is going on around us. The difference between space and earth is just that: you cannot hear in space. The reasoning is this: there are no mediums in space. This means that there is nothing for the waves to bounce off of or travel through. A medium can be a solid, liquid, gas or simply just made of matter. In order to hear there myst be something to let the waves travel through. in space, molecules don't collide regularly because they are stretched far apart and are unable to collide to form sound waves. Therefore there is no eavesdropping in space; let alone talking unless there is a medium.
5. ## shattering glasses

Sound waves are actually very strong. Strong enough to break glasses in fact. Susan the opera singer likes to shatter glasses in her free time by using her voice. She harnesses the idea of resonance to do so. If another object having the same natural frequency is impacted by these sound waves, it may begin to vibrate at this frequency as well. As susan sings, her high pitched tone creates a sound wave that matches the frequency that matches the natural frequency of the glass. Glass resonates or vibrates at the same frequency so energetically that it shatters. When the sound waves strike the glass the phenomena of resonance is illustrated. Resonance occurs when one vibrating object transfers energy to a second object causing it to vibrate. The engr. transfer is most efficient when, compared to the first object, the second object has that same natural frequency.
6. ## Breaking laws of physics - bugs bunny

http://youtu.be/WMtA2gBch_A
7. ## WORK

Work was a tricky subject for me when first learning it in physics class. For some reason it made me think harder than i thought i had to. the equation for work is W=(f)(d) meaning work is the force multiplied by the distance. the distance is a main part of work. take a broken down car for example. Your car was to break down and you had to push it to the nearest help station. No matter how hard you push or how sweaty you get trying- no work is done unless you are able to move the car forward. This was the trickiest part to figure out for me because i always assumed that the harder your trying meant that your putting more work in. But i have come to realize that work in physics and in life is only work if you get distance out of it. After all the definition of work is the "exertion or effort directed to produce or accomplish something." Therefore work is achieved when you accomplish something greater such as moving the car.
8. ## The physics of roundabouts

The Irondequoit roundabout is fairly new,most likely dating back to about 5 years ago. Along with new designs of roads comes the physics that are necessary to build the newest features. Probably one of the easiest physics sections to associate with these roundabouts is centripetal acceleration. As we all know centripetal acceleration is pointed inwards towards the center of the circle. for this acceleration to happen there must be a resultant force , this force is called the centripetal force. the centripetal force measured in newtons can be different forces in different settings such as gravity and friction. take a rubber stopper on a string for example. If you swing the string in a circular pattern the stopper will pull towards the center. once the stopper is released from the string it will fly straight from the facing position. In roundabouts, like the ones in Irondequoit, as a car goes around the circle the centripetal acceleration and force is pulling the car towards the center keeping it from flying off the tracks. Also similar topic involved in race car driving. Thanks to centripetal force and accelleration, cars are less easily flung off the track along with friction keeping them on the track as well.

10. ## newtons laws

this video shows newtons 3 laws in a humorous way. It shows Newton's first law by demonstrating that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. It shows Newtons 2nd law by demonstrating that acceleration is produced when a force acts on a mass. the greater the mass, the greater the force needed to accelerate the object. It shows Newtons 3rd law by showing that for every action there is an equal and opposite reaction. The video also demonstrates gravity and inertia
11. ## catapult

I loved the catapult project. Throughout the project we examined projectiles in a creative way that helped to better my understanding of the physics of projectiles. My catapult was composed of scrap wood, springs, a lacrosse stick, and some wire. The spring was used as the initial source of energy and caused the lacrosse stick to release the softball into the air making it a projectile. Our catapult threw the softball a total of 29 meters. In order to achieve this distance, my partner and I tested out the projectile motion of the softball from the catapult at different angles and heights. We found that 45 degrees was the best angle and would throw the softball the farthest. on the day of the launch we laughed the softball 3 times in order to get the average of the throws and like i said above ours threw 29 meters and it took 3.24 seconds to hit the ground. Once the softball hit the ground it no longer is considered a projectile. overall this assignment helped increase my knowledge of projectile motion.
12. ## friction

without friction nobody would be able to move without falling. Friction depends on two things: the nature of the surface and the normal force. There is also two categories of friction: static (not sliding) and kinetic (sliding). As you can see, in this video an excited sports fan slips on ice while being featured on the news. He slips so suddenly because the friction on ice is 0.02. Clearly the friction of ice is very slim. Another cause is that he went from the friction of the pavement to the friction of the ice which proves to have a significant difference in amount of friction. As he initiated the fall, the force of gravity pulled him down to the pavement where he landed abruptly. He demonstrated kinetic friction because he was sliding.
13. ## physics of diving

Within diving there is evidence of physics. For example when leaving the board it shows projectile motion. The boy creates a force down on the board which is equal to the force of the board pushing back onto the boy. Gravity also acts on the boy by pulling him down. The boy then projects because he has less mass and has nothing stopping him from projecting upwards. Therefore the reaction is the boy being projected into the air. When he comes back down and hits the water he is no longer a projectile.
14. ## Newtons Laws of Motion

wow this is fantastic! I love physics
15. ## Elenas TI selfie

i make math fun with my TI Keyboard Shortcuts Keyboard shortcuts are available for common actions and site navigation.View Keyboard ShortcutsDismiss this message Twitter FAVORITES3 5:38 PM - 11 Sep 2014Flag media Tweet text Reply to @Elena_sophiaa Trends #LHHH Urban Outfitters Ray J #Cilla #DWTS #MadeInAus Omarion #IfIWokeUpWithAmnesia Surge Scotland Â© 2014 Twitter About Help Ads info Close Elena Rohr â€@Elena_sophiaa Sep 11 We make math fun with our TI's #TISelfieContest pic.twitter.com/wc5C4X9Atg Reply Favorite Flag media
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