Past Weeks



November 28th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

This video discusses very energetic events in the universe whose origins are still not entirely clear. Supernovae occur when a massive star can no longer sustain hydrostatic equilibrium and begins to implode under gravity. As the outer shells implode inwards they encounter the inner more dense shell. This results in a bounce, the explosion. This is of course a very simplistic explanation and I urge to go learn more about it if it interests you. The video below discusses what are known as Gamma-Ray Bursts, and people suspect they are related to special types of supernovae.

More down to earth this video shows how to crush a barrel with atmospheric pressure:

Here are some experiments done with fluids that exhibit much of what we have learned so far, waves, collisions, kinetmatics. It even has a dosage of sociologiy for you,

Diving involves a serious change in pressure on the diver’s body,

November 27th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

November 25th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

If you want to learn more about anti-reflective coating, check out this website

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/antiref.html

The demo below shows the incident wave (left), the first reflected wave (center), and the second reflected wave (right) in the case of a thin coating. Keep in mind that all these waves are really superimposed on top of each other and the separation is made only for visualization.


November 21th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Many nice illustrations of waves and boundaries can be found in this website,

http://www.kettering.edu/physics/drussell/Demos/reflect/reflect.html

A very instructive movie describing the reflection off a thin layer can be found here:

“http://www.youtube.com/watch?v=xjMjWtntm9k&feature=related”

November 20th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is the movie we saw in class displaying interference in water

November 18th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

One thing I hadn’t had the chance to cover in class is a technique used by string instrument players to force a higher frequency. It is possible to play higher frequency notes while avoiding the fundamental frequency by clamping the string down only softly rather than all the way. Below is a video of a full piece played in this way. For those of you who have heard a violin before, you are in for a surprise,

Here is a little diagram from Wikipedia that shows you the logic behind the Flageolets,



November 14th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

The following video shows what looks like very short wavelength waves on a guitar. This is only an artefact of the CCD camera of the iPhone that was used to take this picture. The CCD camera scans across as it takes the video and so different parts are being recorded at slightly different times, which makes it look like there are little ripples on the string. These are not real! The actual wavelength is much longer as you can see in the other videos below.

When strumming a guitar, one generally excites the fundamental mode (longest wavelength) as can be seen in this video

Here is another nice demonstration of this effect,

. . . and even better,

November 13th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is a little demonstration of the phenomenon of beats with the visual graph to accompany the audio output (make sure your sound is on),



For a 2D version of the beat phenonemon please visit this website .

November 11th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

We did not get to it in class, maybe later, but there is a beautiful phenomenon called “the missing fundamental”. If you are interested in learning about it check out this website .

If you really like music or interested in the field of psychoacoustics you might enjoy this article in Nature magazine.




November 7th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

November 6th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is a little movie discussing Earth quakes. It’s not very deep so if you want to learn more you might want to try here and even more here.




November 4th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

In class we saw a simple pendulum executing simple motion. Pendulums are fantastic devices because they are so regular and allow us to keep very good track of time. But, if you connect a couple of them together and let them sway with large oscillations, beautiful things emerge – the system becomes chaotic (this is a computer simulation, but you can set it up with real pendulums):




October 30th, 2013

A pendulum executes simple harmonic motion as we will learn in the next class. Below is a little demonstration of what you can do with several pendulums. These pendulums do not know about each other, they simply follow their motion as simple harmonic oscillators.


October 28th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is a video showing buildings in Japan swaying because of an Earth quake. Mass dampers can help alleviate such oscillations and prevent structural damage:



October 24th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

October 23rd, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is how “Spirit” was launched to Mars and “curiosity” rover was deployed, truly inspiring,



If we do not learn how to navigate the stars, we might find ourselves stuck when this happens,



Collisional processes are also responsible for the creation of the galaxy. As this little simulation shows, galaxies formed irrespective of how the matter distribution started, it’s almost inevitable (the only exception I can think about is if dark energy is present – enough of it will cause the universe to expand much too fast for galaxies to form)



Finally, collisions also happen in day to day life – here is why you should drive slowly,


October 21st, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is how little tennis balls collide on the international space station




October 17th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is a clip of a baseball colliding with a wall, notice how elastic the ball becomes under the immense force exerted on it by the wall


October 16th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is a clip showing a computer simulation of structure formation in the universe starting from about 100,000 years after the big bang. The only force involved is the gravitational force. We will never witness these events, they are long gone, nor will we ever live long enough to appreciate the time scales involved, but we can simulate it and view in awe how the universe was formed . . .



This next clip is about how individual galaxies formed. This process is considerably more complex and involves more physics than just gravitational attraction. For example, a supernova going off will inject energy into the galactic medium and can change the distribution of matter.

If you haven’t watched it already, here is how the Earth looks like when you jump from 39 km above the surface (if you ever had doubts that the Earth is round, now is the time to leave them behind). . .


October 10th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

If you haven’t watched it already, here is how the Earth looks like when you jump from 39 km above the surface (if you ever had doubts that the Earth is round, now is the time to leave them behind). . .

October 9th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Here is a very detailed video about the physics of the Large Hadron Collider in Geneva,


October 7th, 2013

You can find the slides from today’s lecture here or for the keynote file here.

Even things that look very solid behave like springs under sufficient compression. Here is a golfball hitting steal which is filmed in slow motion. Notice the oscillations that ensue. We will get back to this issue of oscillations later in the course:





October 3rd, 2013

You can find the slides from today’s lecture here or for the keynote file here.

One of you, R.C., has pointed me to a beautiful website where you can take a voyage through the vast scales of the Universe. You can get there by clicking here.


October 2nd, 2013

You can find the slides from today’s lecture here or for the keynote file here


September 30th, 2013

For next time, please read chapter 4.1 and attempt to solve problem 1 after section 4.1 in the notes. Also try problems 6.12, 6.13, 6.35 in the Schaum textbook.

You can find the slides from today’s lecture here or the keynote presentation here.

This little clip shows the relative sizes of objects in the universe,

The next clip shows a simulation of the growth of structure in the universe on the largest of scale. It is called the Millenium simulation and it is basically the result of the gravitational attraction between particles. Nevertheless if everything was entirely uniform in the beginning, where does this structure come from? Ponder this question while you watch this video and listen to Pink Floyd in the background . . . what seeds the initial fluctuations?

In the clip below you can find a real video showing the effects of drag on a parachuter.





September 26th, 2013

Please consider exercises 3.23, 3.24, 3.70, 3.74 in the textbook.

You can find the slides from today’s lecture here or for the keynote presentation here.

Here is a clip demonstrating how a car goes off the road when taking a turn too fast.


 

Here is a compilation of videos from the International Space Station as it goes around the Earth.


If you want to see all these videos you can go directly to NASA’s webpage here.


September 25th, 2013

Please consider exercises 3.20, 3.30, 3.59, 3.63 in the textbook.

You can find the slides from today’s lecture here, or the keynote file here.

Here is Kiwi, relaxing with a bottle of wine:

 


September 23th, 2013

Please read chapter 3.3 and consider exercises 3.10, 3.54. 3.55, 3.58 in the textbook.

You can find the slides from today’s lecture here. You can download the keynote here.

Here is the clip that I wanted to show you in class today discussing the problem one of the
first astronauts in space encountered when trying to work outside
the spaceship. They forgot about Newton’s third law!

Here are 3 clips by the European Space Agency demonstrating Newton’s laws in space,



September 19th, 2013

Please read chapter 3.2 and consider exercises 3.9, 3.47, 3.49, 3.51 in the textbook.

You can find the slides from today’s lecture here

You can view Miki Ando doing the quadruple jump in the video below.


September 18th, 2013

Please read chapter 3.1 and consider exercises 3.5, 3.6, 3.41, and 3.45 in the textbook.

You can find the slides from today’s lecture here

September 16th, 2013

Please read chapter 2.4 and consider exercises 2.20, 2.34, 2.42 in the textbook.
You can find the slides from today’s lecture here or here for the keynote.

Below is a little clip that demonstrates the rotation of the Moon around the Earth. You can see the different phases of the moon as seen from the outside, from the Earth, and from the Moon. There is something peculiar about the moon. Something that people even wrote songs about. What is it? Why is it?

Also, here is an entertaining (if you can stand the music) clip that explores circular motion in general. Towards the middle the clip mentions forces and some other concepts we haven’t touch upon just yet. We’ll catch up soon enough. . .



September 12th, 2013

Please read chapter 2.3 and consider exercises 1.16, 1.29, 1.37, 1.42 in the textbook.

You can find the slides from today’s lecture here.

Take a look at this Lufthansa plane trying to land and encountering serioues difficulties because of the crosswinds. Traveling with crosswinds is a good example of the problems encountered when moving in more than one dimension. You can see the plane trying to keep a steady one dimensional line with the ground. But, the crosswind is causing it to develop some speed to the side which the plane tries to counter by changing its direction of flight, making it impossible for it to land straight.

Following this link you can find a short article in the New York Times discussing Ronaldo’s physique and skill. Entertaining, but probably mostly public relation effort to that movie discussed in the intro.

Below you can see a footage of the astronaut Harrison Schmitt throwing a hammer on the moon. If you look carefully you can see the hammer.

September 11th, 2013

Please read chapter 2.2 and consider exercises 2.2, 2.5, 2.12, 2.22, 2.28 in the textbook.

You can find the slides from today’s lecture here.

Project Orion as told by historian George Dyson whose father, Freeman Dyson, was one of the original members of the development team.

September 9th, 2013

Please read chapter 2 in the notes about kinematics.
You can find the slides from today’s lecture here in PDF format or in keynote format here.

Last week we saw the launch of Apollo 15’s mission in the 1970’s. Here is a very recent launch (September 6th, 2013) of a NASA rocket heading to the moon for an unmanned mission,

Here is the video for the Chevrolet testdrive in Nurburgring racetrack. Pay attention to the digital display on the bottom right and what it means with regard to the acceleration felt by the driver.

Take a look at the movie below. The narrator is mostly correct, but he says one thing which is wrong regarding astronauts in orbit. Do you know what did the narrator got wrong? Can you correct it? We’ll learn more about it this week.


September 5th, 2013

Please read chapter 2 in the notes about kinematics for next week.

Introduction (keynote presentation – beware, this is a large file 21MB).
Instead of downloading the large keynote file, you can just get the pdf here and watch the movies below.

Launching of Apollo 15 in 1971, you can read more about it here .

This a video of a collision in the ATLAS experiment, the largest particle detector in the world and one of four at the Large Hadron Collider in CERN, Geneva, Switzarland. You can read more about ATLAS and the LHC here .