Resistors

This morning I finally came to understand the inner workings of the two most important resistors of our household. The first one which my mom cannot live without, the hairdryer, and the second one, what the rest of us won’t live without, the toaster.

As I had read last night, they essentially work using the same principle. Both take advantage of the large resistive properties of some materials through which current does not easily flow. As electrons move through such a resistor, they collide with the atoms that make up the resistor. The electrons lose energy in these collisions and the atoms gain it, which increases the temperature of the resistor. This increase in thermal energy is then used to heat up things like toast, or in the case of the hairdryer, is the hot air which dries the hair. 

…..10 minutes later…..

After vainly searching for the resistance of the hairdrier and the toaster, which was not most conveniently labeled on their boxes, I have found a different value that was just as interesting: the power. Using these numbers I decided to calculate just how much money I spend each time I use the toaster or the hairdryer.

Cost per kWh  from HECO: 20.06 cents

Hairdyer: 18.8 cents/half-hour

Toaster: 0.0267 cents/2 minutes of good toasting

Or these number’s really small or is it just me? (maybe because i have never looked at the electric bill before except in an envelope, i have no idea if these rates are good)

(See the red glow? Its very hot taking a picture this close.)

(It is 1875 Watts, thus the name…)

Wires just like the toaster’s are inside…I bet they glow red when it’s working…..

Only the Japanese Can Cook Great Japanese Food

This Saturday, my mom came home from going grocery shopping with an arsenal of Japanese ingredients, determined to try a new dish she had heard about. Unfortunately, dinner wasn’t the success she had hoped for (I advised her not to attempt something she has never even sampled before, but she can be so very stubborn sometimes…she didn’t even know the name, just the recipe!). Honestly speaking, the smell from the kitchen alone was enough to send me scrambling away (and having the strangely brown concoction on my plate wasn’t any more appetizing). However, this story contains more than just the simple warning against trying new things. After reflecting on the comment about how electric fields can be thought of as an odor in the air, I came to imagine the pot of curry-like substance as a strong positively charged particle and myself as a test charge (in reality I am more like  the lab-rabbit for my mom’s culinary experiments). Because of the presence of this pan/positive charge every spot in my home/the universe was given a new property of smell/electric field which pointed away from the horrible source of the odor/positive charge. My/the test-charge’s proximity to the this pot/positive charge determined the strength of my/the test-charge’s repulsion/force vector. The further away from the dish/positive charge the less need there is for me/the test-charge to run away and vice versa.

It even looks scary: We had a lot of leftovers (maybe it tasted/smelled so bad because we used beef instead of pork?)

Raspberry and Crème Brulée Tart

Upon completing the horrors of finals, I got together with some friends to bake. I thought to myself, What better way to relax and edge back to sanity than by making something wickedly delicious to eat? After rifling through the cook book and countless scrumptious looking deserts, we finally decided to try the Raspberry and Crème Brulée Tart. Right away the very idea had my tummy growling. Although I never did get to see our creation come steaming out of the oven (due to unfortunate circumstances, I had to leave early, however, I did get to eat some the next day), on the way home my mind couldn’t help but keep seeing the image of the tart slowly but surely turn golden and crispy….yummm…..Anyway what this image also made me think of was the concept of convection. The red glowing metal heaters at the bottom of the oven warm up the air around it which in turn rises b/c of the decrease in density of the hot air. The heated air then reaches the tart to cook it and the colder air from the top of the oven flows down to be warmed in turn. Now I finally understand the difference between baking and broiling. When broiling the top burner turns on and stays on to generate enough infrared radiation to brown things like steak etc. On the other hand baking is basically meant to surround the cake or other pastry with hot air and the bottom burner only hits the bottom of the cake pan…..I always thought baking and broiling were pretty much the same thing….guess not.

This isn’t the actual thing, but it looks pretty close (…sorry doc, don’t have an actual photo…but to make up for it I added another photo of the cake I made a couple of weeks ago!)

Its a good thing I didn’t actually try broil this one….

Instead of Brushing Your Hair Every Morning…

After reading about electrostatic forces last night, I decided to try it out this morning (actually more like afternoon….i am finally catching up on my sleep). So upon discovering an abundant supply of balloons (we always have balloons tucked up somewhere in the closets), I pumped life into Happy Balloon the Second pictured bellow.

HAPPY BALLOON II

Starting with the neutrally charged balloon and some strands of my hair, I rubbed the two together to get the electrons flowing. Withing about 10 seconds I ended up with a positively charged balloon and negatively charged head as the electrons from the balloon transfered to the strands of hair. Thus static electricity was created and the terrific results literally made my hair stand.

 

(Taking your own picture like this is really hard!)

Although it wasn’t anything to rival the mini- Van de Graaff generator from eighth grade, I consider this Saturday morning well spent in pursuit of some ever-baffling physical knowledge. Plus, I got to play with balloons!

(Whats with the teddy bear?…in case you can’t tell, the blue are plus signs, the red minus, and the brown thingys are arrows)

I should get back to studying for finals now….waaaaaaaaaaaaaaaaaaaahhhhh!

Some of My Physics Related Observations Which I Was Too Lazy to Write About During X-Mas Break

Although I had promised myself to get started with finals, whip up some extra credits and rewrites, keep up with physics blogs, and even start exercising again, all of these things were completely forgotten during the refreshing but brief x-mas break while I lay at home in a lazy stupor. However, though my time seemed to have been absolutely wasted, it was not due in any part to the lack of physical revelations. Off the top of my head, I can come up with at least two very memorable instances where my mind inadvertently switched gears to contemplate the fascinating realm of physics.The first of which was triggered by the loud bang of an exploding balloon.

Exhibit A: Happy Balloon

What the happy balloon pictured above didn’t know was that the laws of physics had already spelled out its imminent destruction (otherwise it wouldn’t have been so very happy). Our orange friend here had been first inflated early in the morning around 9 a.m. which gave it approximately 3 hours of lifetime before the hot noon-sun shining through the window eventually lead to its demise. As Charles Law (V/T) points out the rise in temperature as the day progressed would cause the volume of gas within the balloon to increase, and the already taut balloon would no longer be able to hold the increased volume. As my family had blown several balloons in celebration of the new years, we were surprised throughout the day with their pops. Soon, my brother and I were forced to remove them for fear of invoking my mom’s wrath.

Exhibit B: At Ice Palace

The second epiphany occurred at the only icy/snowy place on Oahu: Ice Palace. Since I had been pouting for a white Christmas for the last month or so, I finally convinced my parents to go to the nearest thing on the island. Upon arriving at the ring I found myself quite enjoying myself though I really didn’t know how to skate at all. I suppose it is easy to be dragged along by an expert skater like my dad (I really didn’t do much except keep my balance). After a while, I noticed that the ice had turned rather slushy and that the going wasn’t so smooth anymore. Further investigation revealed that the ice was criss-crossed with thin lines created by the skates. From this I deduced that the melting could be explained by Gay-Lussac’s Law relating pressure and temperature (P/T). When pressure was exerted on the ice by passing skaters, with everything else constant, the temperature went up which led the ice to melt.

(I am about to fall…I managed to fall only 6 times…but I still earned some formidable looking bruises)

So all this really adds up to the Ideal Gas Law PV = nRT which related all of the three mentioned above.

The Chicken Called Duck, Embodiment of the Christmas Spirit & Projectile Motion

With the threat of physics test looming over the week-end, I have been meditating on ways to prepare myself for the inevitable headaches and panics. I concluded that a review of projectile motion would be the best thing to keep me on top shape because it should guarantee me at least one free response (after all when has there ever been a test without one projectile motion problem? Unless I manage to jinx it somehow with my post…). So, the brilliant maneuver that set me to thinking about projectile motion in the first place was all thanks to a friend who gave me a dancing chicken (whom I call duck for no valid reasons) last Christmas.

(There is dust on its hat…We really should clean out the hallway…)

The chicken, which had been sitting on a useless stack of old books (and a not-so-useless box of chocolates), somersaulted to the floor midway into it’s dance.

(Huge eyeballs…bit scary) (Calculus-As if!) (It glows!)

On the whole, the important facts to remember here are the kinematic equations and no one will get hurt (unless you used them for a spring-mass system in which case public ridicule is your fate). The classic projectile motion problem asks for the x displacement. In that situation, we use the change in y distance (the height of fall)=0.5 gravity time-squared equation to determine the travel time of the object. Once time is found, the rest is pie! The initial velocity of the chicken (or whatever object) is its x velocity and all we need to know to solve is x-displacement = vt. The chicken’s velocity when it hits the floor can be calculated by pythagorizing the x and y velocities (the final y velocties = gravity time). Yup….That’s projectile motion in a nutshell.

Canoe Ride

Last Weekend, before the all the raining started and there actually was some sunshine, I went on a canoe “promenade” (as the French call it) around Waikiki and Diamond Head, where I notices two things. First of which was that the Ala Wai truly does contain some rather mysterious inhabitants, one of the most numerous is (I am told) the jellyfish. Although they are be pretty eerie  floating around in the green and murky water, once captured, they resemble (in the most flattering of terms) a bucket of mucus.

(Eeeewwwww……)

The more important finding of course concerned the fundamental law of physics. In brief, all through my relaxing (because the canoe had motors and I didn’t need to lift a finger) canoe trip I couldn’t help bad thinking about Archimedes and his theory about buoyancy (it had taken over my mind!). I pictured the force of buoyancy going up and the combined weights of the passengers and the canoe pointing down, and I said to myself that I could figure out the volume of boat submerged using the Fb = pgV equation (that is, if everyone consented to reveal their weight). The result could be interesting since the canoe is so irregularly/asymmetrically shaped.

(See the motor in the back? No need for paddles! Yeah!)

P.S.   It occurs to me: This blog would have worked better last week, and last week’s topic could have been better this week…bad planning on my part…

Update on Harmonicas

I recently received some interesting and new (more accurate) information on the topic of glass harmonicas thanks to Mr. William Zeitler,  a  Medal of Honor recipient from the National Society of the Daughters of the American Revolution for his dedication to the revival of the harmonica.

As it turns out, it was Benjamin Franklin who invented the musical instrument based on the wet-finger-around-the-wine-glass idea. Ben Franklin built and played one himself. It was in fact very popular in the 1800s, and not  a feared-musical-implement as I led some to believe. Even Mozart and Beethoven composed for it. However, musical tastes changed and by about 1820 it had all but disappeared.

Now that I have been cured of my ignorance, let us celebrate some of the shortcomings/unreliabilities of  Wikipedia…which doesn’t always give the best of facts…

P.S. I can’t wait for Christmas Break!

Thanksgiving: The Day of the Turkey, Our Almost-National-Bird-By-Great-Thinker-Ben-Franklin

So, after two days of turkey eating, intense shopping, and almost forgetting to write a physics related post (but I still remembered!), I have finally uncovered the great secrets of the harmonica. As a way of passing the boredom of the annual thanksgiving feast, we cleverly but rather unsuccessfully attempted to play “Jingle Bells” with our wine (in my case juice) glasses. By wetting the edge of the glasses and running one’s finger over the rim, one creates friction which then produces vibration and sound waves, which are mechanical longitudinal waves consisting of regions of high and low pressure! This is when I blithely announced to the world that “I could write about glasses in my physics blog!” and received a grunt, a half-choked guffaw, and a bunch of quizzical looks. But back to the topic at hand. As we experimented with the our glasses, we obviously realized that the sound made by the glass depended on the level of drink inside. From this, I deduced that the amount of juice in my glass must be affecting the frequency, and thus the pitch of the sound. In brief, the glass harmonica uses the same principles as the wine-glasses to produce music. However, it seems that there was a widely held belief that listening to the harmonica caused insanity (huh?) and the instrument never became very popular. In fact, the only disorienting quality of the harmonica is due to its sound range between 1,000-4,000 hertz, which is the scope of frequencies the human brain does not quite know how to locate or identify precisely.

Some Examples…….

Some Physical Activity

(I changed my theme! Actually, is it even winter yet? After Thanksgiving?….Oh wells….)

Anyways, other than procrastinating and starring at the computer this Friday, I was forced on to play tennis and basketball with my parents for some “family time” (this is something we do like twice a year whenever my parents feel like we need physical activity, usually I am pretty opposed to the idea since Fridays evenings are my sleep and do-nothing time). Hence, while trying to keep myself awake and concentrate on hitting the tiny tennis ball at the same time, I came to the conclusion that tennis is all about physics. Consider for a moment the collision of the ball and the racquet, its a classic example of the conservation of momentum! Furthermore, basketball is all about projectile motion. I actually managed to apply the idea to get every single one of my free throws! (which is amazing seeing as I am a very very poor player). I don’t mean to say that I actually calculated the x and y velocities and the distance and height of the hoop, but still approximating the values works nicely.

That’s all for now…….and it looks like a hectic week coming along (how can one have 4 tests, 2 quizzes, and 2 papers due in three days on top of everything else?) The break is the only thing keeping me sane….    -.-  (probably wasn’t a good idea to waste the weekend….)

    

Cell picture = bad focus