Lenses

I have really, really big eyes.  Okay, just one big eye… like the cyclops in The Odyssey >0)

Because the object, my eye, is between the lens and one of its foci, the image produced is upright and larger than the object.

When I place the lens against the mirror, this weird thing happens… not really sure how it works.  Light from all over reflects off the mirror and produces a virtual image behind the mirror.  This virtual image serves as the virtual object for the lens.  The lens creates a real image that is inverted and smaller than the virtual object, since the virtual object is far behind the focus of the lens.  If I were to slowly move the lens toward myself, you would be able to see more than one image.

This lens is actually part of a television that my dad took apart — umm — tried to fix.  It’s pretty heavy and thick, around an inch at the middle.  He said it’s used to focus light onto one point, or a pixel, or something.

Convex mirrors

A few days ago in orchestra, I saw a mechanical metronome on the piano.  It was really tiny and cute XD unlike most other mechanical metronomes, which look something like this:

The one in the orchestra room was more like this one, except red:

Anyway… since I couldn’t find much to write about this week… I’ll revisit the pendulum from last week.

The surfaces of each of the small metal spheres acts like convex mirrors.  Since the pendulum is placed in the corner of the room, light from afar hits the spheres.  If you zoom in on the spheres, you can see that almost the entire room is reflected in the sphere.  The image in a convex mirror is always virtual and smaller than the object.  The further away from the mirror the object is, the smaller its image.

This is the sphere at the top of the pendulum.  It’s not very clear, but at the top, you can see the clock; in the center, me in my ridiculously large OSB shirt, holding a camera; and below, the two bears that were in the first picture.

EDIT: I almost forgot!!! D:

Projectile motion~!

SNUFFLES <3

Metronomes

Metronomes provide a way for musicians to be sure that they are rhythmically accurate by providing a constant beat, although some musicians criticize the lack of musicality that may come with metronome use… but I don’t think metronome use will always lead to mechanical playing.  Wikipedia is distracting XP Apparently Heifetz used gut strings and Auer believed that using a shoulder rest diminishes the volume of the violin by 1/3…

There are two main types of metronomes: mechanical and electronic.  Mechanical metronomes use a pendulum that has two weights, one on top and one on the bottom.  The weight on the top can be slid to adjust the tempo.  This pendulum is a physical pendulum, somewhat similar to the pendulum shown below:

Taking a video didn’t work too well… so I just screen-shotted it.  Artwork by yunyun in the background :)

I don’t have a mechanical metronome, but it would be cool if I did.  Instead, I have one of these:

There is a circuit board inside which makes the metronome beat regularly at different set tempos, and the battery provides an emf for the metronome.  A small red light also turns on and off with each beat.  I don’t really understand how all this happens, but according to this site and my dad XP… different resistors are used for different tempos, or frequencies.  The tempo markings are the number of times the metronome beats in a minute.

Magnets

Some things are magnets, and some things are not magnets…

These are my “super strong magnets.”  (That’s what it says in the thing they came in.)  The harp, french horn, piano, timpani, and trumpet are all attracted toward the violin, not only because they admire the violin’s beautiful sound and splendid superiority, but also because the north poles of the magnets are attracted to the south pole of the violin magnet.  (I’ll assume that the north pole is at the top of the instrument and the south is at the bottom).  But there isn’t really any significant attraction between the violin and the other instruments.  They are too far from the violin, and the magnetic field is not very strong… I just wanted a picture with the violin in the center :P

Here you can see the north-south attraction more clearly.

Some things, like the runners of my sled, are not magnets, but can develop their own magnetic field when they are in an external magnetic field.  The sled runners are not ferromagnets, since their magnetic field does not stay after the instrument magnets are removed.

My pig, however, is glass and is not attracted to magnets.  She would rather practice the piano.  Sometimes she likes to fly, too ~ and she’s been learning how to fly on her own, without help from the magic carpet in the first picture.

奥运会!

The Winter Olympics in Vancouver started this weekend!! Luckily, it was also no homework weekend :)

Yesterday, I watched men’s luge ~ since the luge track is on a mountain and goes down, it’s pretty scary to watch (at least, for me it is).  Some of the athletes reach speeds of roughly 90 mph at the end of the track.  Assuming that all of their initial potential energy was converted to kinetic energy, the athletes descend from a height of 1.07e6 km… not sure if I did the calculations correctly.  Oh well ~ However, some energy is lost due to friction and sound – the initial height is higher than what was calculated.

Rest in peace, Nodar Kumaritashvili.

Figure skating is really fun to watch this year – especially with Shen Xue and Zhao Hongbo ~

加油！

Too bad there’s school tomorrow… can’t really watch TV… D:

Congratulations to Canada’s Alexandre Bilodeau!

Tuning

On Saturday, we had the Concerto Concert.  About an hour before the concert, the Hafinator tunes each of us individually.  The string instruments are tuned by turning the pegs, which increases the tension of the string.  The velocity increases with increasing tension, and frequency increases with velocity.  The tighter the string is, the higher the string is tuned.  For wind instruments, they pull out or push in different parts of the instrument to increase or decrease the length of the “pipe.”  Frequency is equal to nv/2L.  As L increases, frequency decreases, and as L decreases, frequency increases.

Some pictures of instruments ~

It’s kind of sad that they just sit in the display, and no one plays them…

Different shapes of the body of a string instrument affects the tone of the instrument.  Violin makers have experimented with the length of the body, the shape of the f-holes, the varnish, and other things.  Stradivarius tried to make violins with a longer body, but he found that those didn’t work so well.  They were good instruments, but lacking in something, I forgot what… Modern violin makers try to imitate the varnish that was used to make the old instruments, but it is very difficult to do so.  I heard that the varnish on a lot of the older violins was made from a whole bunch of chemicals that violin makers got from drugstores? really cheap, and they just mixed them together.

Cherubinoooo!

On Wednesday, I saw Le Nozze di Figaro.  In one scene, Count Almaviva suspects the Countess has been unfaithful and that she is hiding a man inside the closet of their room.  Cherubino, the young page, is indeed hidden inside the closet, but the Countess tells the Count that Susanna is inside, trying on her wedding dress.  The count does not believe her and exits the room with the countess, leaving Cherubino locked inside.  The strange part is that the door cannot be opened from the inside when locked, but it can be opened from the outside…  Anyway, Susanna entered the room unnoticed while the count and countess were talking.

Cherubino must find a way to escape – and he plans to jump out the window.  Susanna fears that he will jump to his death.  The impulse, the change in momentum, of his collision with the ground may harm him if the time that the force of his weight is applied to the ground is too short.  The higher the window is above the ground, the higher his velocity at landing will be.  Luckily, Cherubino lands in the gardener’s bushes, which increase the time and decrease the force of the collision.

Noblesse and Beige!  I have no idea who these people are, but 후회는 없어 is pretty!  Beige has a nice voice, but Noblesse’s rapping is strange >_>

Green piano! O_o  It bursts into flames at the end…

And and and… !!

Cute, yes?  ^__^

I don’t know what to blog about :O

There was yet another concert this weekend: the chamber music recital! :)

Our quartet played Debussy ~ one of the movements, which we did not play, has a lot of pizzicato, instead of bowed notes.  The sound is produced by pulling the string and momentarily increasing its tension before letting go.  In this method of producing a sound from the violin, the beginning of the note is clearly defined, but the sound is not sustained for a very long time.

Graphs of amplitude vs. time might look like this:

Pizzicato:

Bow:

Graphs of frequency vs. time:

My vibrato (pitifully irregular oscillations – the bare minimum of what you might call vibrato):

… as opposed to the way vibrato *should* look:

One of the competition judges two weeks ago even drew a sine wave on my comment sheet XD

It seems like there’s a concert almost every other week… O_o  So stressful… but fun at the same time :)

Concerto Concert is in two weeks!  :D

Crab

Last night, we had crab for dinner :)

I guess the people who designed my crab-cracking device enjoyed the notion of savage crabs attacking one another so that we lazy humans can just let them destroy each other, instead of cracking the crab ourselves D:<

Torque is applied to both parts of the crab cracker, with the center of rotation where the two parts of the pincer meet.  The torque is equal to rFsinθ. Unfortunately, during dinner, I didn’t get to calculate the force that I used or the angle at which the force was directed.  The area that cracks the crab has teeth, which increases the friction between the cracker and the crab, so the crab won’t slip away.  This area of my crab cracker is gray; the paint came off because of the friction.

Krabby is cute :)  Look at those pincers!

[Look at that horse!  The bushy tail, the big teeth, the hooves...]

155.687756

Earlier this week, in PE, we had our bench press test in which we were to lift a certain amount ten times. Not to be daunted by the others’ awe-inspiring show of strength, with a lot of determination and effort, I managed to lift 155.687756 N.  I consider that an achievement… that’s 22 N more than what I could lift a year ago.  And it felt like I was lifting a huge boulder.

Each time I lifted the weight up, the work that I did (W=Fdcostheta) was about 48.768 J.  As I brought the weight down, the work that I did was negative, -48.768 J.  The net work that I performed was 0 J.  I did the same amount of work as those who lifted more than I.  This story might have a moral.

I don’t have time for a real picture or a drawing, so this week will be another Paint drawing.

Please excuse the roundness of the boulder and ignore its strange hue of brown.