Thermal physics

2008-09-05T04:17:00.001-07:00

Don't miss my posts :}

Cause this is gonna be my last one. It's Completely nothing about physics, It's just on my thoughts :]

Special thanks to:

Firstly, i want to thank Blogger for the auto-saving feature. My labtop is seriously corrupted (Not b'cos i watched anything..) ,spoilt and laoya already. I believe endless viruses will be detected if it ever goes for a scan. The reason i'm very happy because despite the fact that my labtop hanged (minimun 5 times), my posts weren't lost so i did not go mad or crazy.

Secondly, Special thanks to Yahoo and Google for the awesome pictures that were shown (although not all) just by seconds and Youtube for the videos:D

Lastly, All the Uploaders that provided the (sources above) the pictures and videos i've used to show on my blog.
I'm seriously glad i've completed this exercise and i've learnt that these 3 chapters are actually very applicational right? Hahha. I'm also glad i'm not talking to myself cause there are people who reads :] *

So i'm going to end off with some Jokes that i've just read from Reader's digest cause, last post already mah. Don't want end of with such a sad note:]

Joke #1: Before writing a prescription for my young daughter, the paudiatrician asked her if she was allergic to anything. Erica whispered something in his ear. That night, before giving her the medicine, I read the directions on the bottle. The doctor had warned, "Do not take with Broccoli." (:

# Joke 2: 'I work as a piano teacher who makes house calls. As i left one student's house last week, the nanny asked me how many people i teach each day. I replied, "Between five and seven." My eight-year-old student, Olivia, piped up immediately. "I know that number: It's six!"

#Joke 3: A man walks into a wine bar with his dog. 'Excuse me' said the barman. 'No dogs allowed.' 'It's OK,' the man responds. 'This is a super-intelligent, talking dog.' 'Oh yeah?' Sneers the man. 'Prove it.' 'What grows on trees?' the man ask the animal. 'Bark,bark,' replies the dog. 'What do you find on the top of a house?' 'Roof roof,' says the mutt. 'What is the opposite of smooth?' 'Rough rough.' growls the hound. The barman realizes he's being made a fool and throws the man and his dog out. 'Well i'm terribly sorry abut that Peter,'' says the dog to his owner outside the pavement. 'Just out of curiosity, which one did i get wrong?'

#Joke 4: It's really humid in the woods, so the two hiking buddies remove their shirts and shoes. But when they spot a sign saying "Beware of the bears'', one of them stops to put his shoes back on. ''What's the point?'' the other says. ''You can outrun a bear. '' , ''Actually,'' says his friend, ''all i have to do is to outrun you.''
Haha. I'M RETARDED. Bye:]

2008-09-04T19:56:00.000-07:00

Hi. I'm going to start on chapter 9.

Just flipped the textbook and internal energy reminds me of those 'Gu dai' shows with martial arts where the heros fight with the baddies and somehow their internal energy got disrupted and they go a little bonkus D:

Actually those shows made me super impressed in the past until one fine day i found out that there's alot of Computer editing involved. Why don't such '威风' martial arts exist? D:

Oh boy, I found a song on this chapter, It's quite catchy. (Don't let me catch you singing behind the computer:) Watch it leh :x

Let's start on this chapter for real.

Internal energy: is the total energy of particles comprising of Kinetic energy and potential energy.

Kinetic compound: Due to vibrations, directly related to temperature.

Potential compound: Due to stretching and compressing of bonds, related to distance of particles.

Melting: Change of state from solid to liquid. For a pure substance, the degree of melting is at a definate temperature known as the melting point.

The melting point of ice into water is 0 degrees and during the change of state, there is no change in temperature.

Now everyone please watch this video D: Don't worry, it only takes less than 30 seconds, It's so traumatizing to see one big chunk of ice caps melting and falling into the sea like how we pour flour to bake our cakes. Must watch k. :]

This is a real life example of melting. &I don't know how i should be reacting. D:

Anyway, a solid melts when the intermolecular bonds of the solid is broken when thermal energy is supplied. In this way, the molecules can break free and move like how liquid molecules should be moving then. (Lessly packed, not in an arrangement.)

Solidification/Freezing point: It is a process that occur when a liquid changes into a solid. Water freezes to form ice at 0degrees. The freezing point is constant for a pure substance and during the change of state, there is no change in temperature.
This is seriously beautiful leh D: i just searched 'Freezing' in google and this caught my attention. @*#()!^ Pretty.

Boiling: It is when a pure liquid changes into water vapour at a fixed or constant temperature, which is also known as the boiling point.

Condensation: It is when water vapour is cooled at a fixed or constant temperature. Thermal energy is given out during this process.

How do we determine the boiling/condenstation point? Answer: Heat/cool the water until there's a change. Like for boiling, heat until the water boils and that is the boiling/condensation point.

When the intermolecular forces break and the molecules can move more freely, we can say the state of liquid has changed to gas.

Evaporation :}

EH! I didn't know evaporation causes the cooling that we feel after being out of the pool. I thought it was the stupid wind. (@#@#(* =.=

Very creative picture done by just by using 'paint' :D Still got animation somemore!

Differences of Boiling and evaporation:

Difference #1 : Boiling occurs at a fixed temperature while evaporation occurs at any temperature. (You can think of it logically, like imagining your clothes can only dry at 28.976 degrees, that's of course impossible:)

Difference #2: Boiling is a quick process while evaporation is a slow process. (If boiling was a slow process, how long would chemistry practical lessons take? :)

Difference #3: Boiling takes place throughout the liquid while evaporation takes place only at the liquid surface.

Difference #4: Boiling forms bubbles while evaporation do not.

Difference #5: Temperature remains constant for boiling while temperature varies for evaporation.

Difference 6: Thermal energy must be supplied an energy souce for boiling to take place while evaporation can take place on it's own due to the thermal energy supplied by the surroundings.

How does evaporation occur?

It occurs when the more energetic molecules overcome the downward attractive forces of other molecules and escape, carrying thermal energy with it.

Factors affecting the rate of evaporation:

1. Temperature: The higher the temp, the faster a liquid evaporates due to the larger amount of energetic molecules running away from home :)

2. Humidity: The higher the humidity, the lower the rate of evaporation.

3. Surface area of a liquid:If the liquid has a bigger surface area, the rate of evaporation would be faster:)

4. The movemen tof air: The rate of evaporation is faster in moving air than in still air. I think that's why it's cooler with the fan/aircon right? (:

5. Pressure: The lower the atmospheric pressure, the higher the rate of evaporation

6. Boiling point of land: Liquids with lower boiling points will evaporate faster.

Hehe. Now for the Applications of evaporation:

1. When you're having a fever, a wet and cold towel will leave a cooling effect on your forehead when it evaporates, keeping down the temperature :)

2. Cooling effect on your skin after applying perfume/When your perspiration evaporates.

3. Refridgerator uses the principals of condenstation and evaporation:)

4. Clothes dry due to evaporation :)

That's all for lessons forever and ever and ever D:

But i'll still be posting one more to share my thoughts :D

Random

2008-09-04T13:00:00.000-07:00

Hey:D

I've already finished blogging on chapter 9, But i'll only post it up after i've returned home in the evening:]

I just read Reader's Digest and i found this rather humorous:

"I went into a a McDonald's yesterday and said, "I'd like some fries." The girl at the counter said,"Would you like some fries with that?"

{: Or maybe i'm the only retarded one. Hahaha. Bye.

Video time

2008-09-04T03:53:00.000-07:00

Now it's video time! :D It's actually like a commercial break before chapter 9, Just that it is educational. These videos are of different learning aspects:D

#1 Video: States of mater. Rating : 4/5

I'm advertising for this video k! Cause I think this video is fab. It illustrates the states of matter with real life experiments. (I've watched too many of those fake ball-moving stuff.) It also shows a wonderful experiment on gases too. It looks just like a steam-water fountain :] Other than that, it also shows the 4th state of matter, Plasma:D (And if they say this video is not avaliable anymore, refresh:]! I was so upset when i thought they removed it. Luckily not:)

#2: Brownian motion. Rating 2.5/5

I found this quite amazing. (At least among all the rest which is ..... *Not saying.*)

#3 : Convectional currents. Rating : 2.9/5

I don't know if i'll consider this interesting, but i do like this experiment. Showing convectional currents with those beautiful colours.

Chapter 8

2008-09-02T02:27:00.000-07:00

Hello!:D It's time for chapter 8 - Transfer of Thermal Energy.

I'll keep it as short as possible, to avoid being a Second textbook:)

Firstly, grasp the basics. Note that:

Thermal energy flowers from a region of higher temperature to lower temp and there are 3 ways of transfer.

I. Conduction (Transfer of energy in a medium while the medium stays unmoved.)

Concepts of conduction:

1. A medium is needed for energy transfer but the medium definately does not move. --------------------------------------------------------------- ------------------------------------------------
2. Different materials affect the conduction rate. Think about: Insulator, Conductor. :} -------------------- ----------------------------------------------------------------------------------------------
Good conductors: Metals ; Copper,silver,iron.
Good insulators: Non-mentals ; Plastic,metal,wood,brick. (I think you get the idea, right?) --------------------------------------------------------------- ------------------------------------
3. The difference is that metals Do have spare electrons while non-metals don't.

4. So what happens is when thermal energy is present, molecules from the end vibrate and collide to the rest, causing all to vibrate. ---------------------

5. The spare elections in metals gain K.E too, and move faster. Now you know why conductors transfer heat energy so fast - They're not called conductors for show:) ------ ---------------------------------------------------------------------
6. Lastly, Solids conduct energy much faster than gas cause of the spacing they have.

Below is an example of an experiment regarding conduction:)

II. Convection

Please don't get bored! I'm trying my best, really :D

Concepts of Convection:

1.It only applies for Liquids and Gases, but not solids.

2. Since it applies for 2, I will illustrate my point with an 'A' so it can be applied for both liquids and gas.

Tiko Bear is a retarded bear, and one day, he decides to play with fire. He heats A. A expanded and produced B. B is hot and less dense than the surrounding, so it rises up. A, being heavy and cool, sinks down. This movement sets up a convectional current, due to difference in density. Tiko bear was so happy with what he saw that he laughed so hard till he died. D: (Sorry.)

Here's a video of an experiment to prove convection currents. It's actually a physics lesson and the experiment is done by the rather humorous teacher. If you have 3 minutes to spare, you can try watching this. :)

The end. So hence, Convection is just the transfer of energy by means of currents in a fluid.

III. Radiation

Concepts of radiation:

1.It is the emission of infrared waves from the surface of bodies w/o a medium.

2. It can take place in vacuum.

3. Your knowledge tells you not to wear black when the weather's hot. This is because Colour affects radiation.

4. Dull surfaces absorb better than a shiny cinderella shoe.

5. Surface temperature affects the rate of infrared.

6. Larger surface area will result in a higher rate of infrared radiation.

IV. Applications of Thermal Energy Transfer.

I'm not tellin' you anything! Go find them in your kitchen! (No la, i know you also 不稀罕 lor.）But i still have to say it, Sorry :D

*Updated:D*
Considering the fact that the applications are really important, i shall update this:\

1. Conduction!

-The uses of good conductors of heat like : Cooking utensils, iron rods and heat exchangers. This is because they are made up of metals which means good conductors of heat, which further means that heat can be travelled quickly through these conductors.

-The uses of good insulators of heat like : Handles of appliances (Surely you don't want to get burnt:), Table mats, Sawdust, wooden ladles, woollen clothes etcetc :D

2. Convection!

-Common applications include:

Electric kettles: (The heating coil is placed at the bottom so as to aid the transfer of thermal energy in water by convection.)
Air conditioners: Ever wondered why air conditioners are always placed on top of the room? That is because of the setting up of convectional currents such that warm air and cool air can rotate.
Refriderators: Freezing unit is placed at the top to facilitate the setting up of convection currents.

3. Radiation!

-Common applications:

Teapots (Shiny teapots can keep tea warm for a longer time and keep cool liquids for a longer time:)
Greenhouse (Infrared radiation from the sun passes through the glass roof, it warms up the soil and plants in the greenhouse. In addition, the infrared radiation emitted by the contents gets trapped and the temperature increases over time.)
Vacuum flasks. Minimize heat lost by conduction, convection,radiation and evaporation.

Sayonara:D

Chapter 7

2008-09-01T17:00:00.000-07:00

7.1 : The 3 states of matter.

Ok, Look here! :D Solid state, liquid state, gaseous state.
I think all of em' is clearly known to us by now, Right?

Okay, So generally, the Kinetic model of matter,
is the assumption of moving particles, in continous motion.

Now let me tell you what i've learnt... :]

This is a model of a solid. Just by looking, I can infer that it's closely packed, it's in an orderly arrangement and it occupys little space.

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Okay, So what has this got to do with the movement? Let's say, you're stuck in a crowded train, with 10,000 people in it, i doubt you can even move! (Frankly speaking, would anyone even board such a train?) Okay anyway, ----------

This goes to show a few things:

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Let's first say, you represent a molecule. Therefore, it is known that:

1. You can only vibrate on fixed position. (Right? Don't try anything funny with 10,000 people there)

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2. You also held by strong intermolecular bonds. (I'm so sorry, but you can imagine yourself holding strangers' hands for this case.)----------------------------------------

Yap, So hence, i can conclude that a solid has:

High density, fixed volumes and shapes, vibrate on it's spot, are closely packed and are held by strong bonds.

Clear enough?:)

Next, A liquid is somehow alike to a solid. You can now imagine yourself being locked in a jail. You definately can't break out of the jail right? I'm not doubting anyone's abilities but it's would be much better if you wouldn't try anything funny.

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So, bring this example into the structure of a liquid. It's a little messy in terms of the arrangement.

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It's randomly arranged and the molecules are not that packed together. (I don't think they'll be so cruel to squeeze too many people in a cell.)

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The molecules in the liquids can move freely, however, only inside the medium.

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Yap, and it'll also follow the shape of the vessel. They do not have a definate shape but they do have a definate volume. Lastly, it's the gaseous state. The molecules are obviously very far apart and can travel wherever they want.

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(It's like when you're wild and i don't know where you'll run off to.)

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They do not stick to any shape and they do not have a fix volume too.

Of course, low densities, little attraction between them and blablabla:]

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I'm losing my cool cause it's getting a lil boring,

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OK, so it's the last part now. Ever heard of Brownian motion??

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It's actually the irregular movement of smoke particles in air:)

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Temperature is one of the factors that'll change the motion.

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Higher temperature - Motion of smoke particles will be more vigorous.

Lower temperature - Motion of particles will be less agitated.

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This is because when temperature increases, larger amount of thermal energy is converted to kinetic energy, giving the molecules more energy.

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This is how brownian movement looks like, and you can also watch a video on it in my later posts :D----------------------------------------------------------------------------
Yap, that's all. Hahahahaha. Bye:D:D:D

Waves

2008-08-29T21:24:00.000-07:00

Hello!:]

I feel so weird talking to myself.
I don't have the mood to post about physics now :@

Let's all wait till a Tsunami strikes first then! :}

Byebye. {Bored}