Penguins, thermoflasks & the end.

oh no wait, Haha I wanna talk about a few last things!


Firstly, the penguin.

Penguins are awesome creatures who amaze me by their surprisngly good understanding of the transfer of thermal energy. HAHA.
I know you all will ask why, so I shall explain myself.

Okay, so everyone knows that penguins have dense feathers that can trap a lot of air in between them to keep them warm right. Not forgetting the thick layers of fats they have under their skin, which provide a good thermal insulation to wistand extremely cold temperatures. But you know what, what amazes me is the fact that penguins actually behave in a certain way. They actually huddle close together, in big packs, to protect themselves from the cold as huddling reduces the surface area of the body exposed to the extremely cold weather and this reduces heat loss through convection, conduction and even radiation!

AMAZING EH?

Haha oh and secondly, this amazing thing called the thermo-flask.
HAHA YEAH.

Well, as you can see from the picture right. How it's built and made and all.
I find it really impressive! :D
Really shows the creator/inventor's understanding of the transfer of thermal energy! HAHA.

1) The stopper is made of plastic cause plastic is a poor conductor of heat.
2) Conduction through the trapped air above the liquid is very minimal since air is a very poor conductor of heat
3) Conduction and convection through the sides of the flask areprevented by the vacuum between the double-glass walls of the flask.
4) To minimize heat loss through radiation, the walls of the glass are silvered so as to reflect the radiant heat back into the hot liquid. Convection and evaporation can only occur when the plastic stopper is removed during use.

Anyways, okay to sum up this chapter again, :D
I would like to say that after not only studying this chapter but also doing a blog on this chapter,
I have come to realize how this chapter is really useful and has so so so many applications in real life, reagring heat/thermal energy and the things around us :D

Haha, cool.
And so I shall end my physics project here, this blog is completed :) :D
IT IS DONE!!!

APPLICATIONS IN REAL LIFE.

I shall end off this blog and my physics project with this:

Only some of the many many many applications of thermal energy transfer in real life!

CONDUCTION

Good conductors of heat!
(If thermal energy has to be transfered quickly through a substance, good conductors of heat such as metlas are used)
E.G.
-Cooking utensils
-Soldering iron rods
-Heat exchangers

Bad conductors of heat (Insulators)!
(Insulators are really useful if we want to minimize the loss of thermal energy or prevent thermal energy from being transferred quickly)
E.G.
-Handles of appliances or utensils
-Table mats
-Sawdust
-Wooden ladles
-Woollen clothes
-Fibreglass, felt and expended polysterene foam (used in the walls of housesm ice boxes and refrigerators)

CONVECTION

Common uses would be:
-Electric kettles
-Household hot water systems
-Air conditioners
-Refrigerators

RADIATION

Common applications:
-Teapots
-Greenhouses

SUMMING UP.

To sum up,
here's everything I've learnt in this chapter :)

-Transfer of thermal energy (Why) ~ Thermal equilibrium
-Transfer of thermal energy (How) ~ conduction, convection, radiation!

Yep, those are the main points very briefly :))

Let's radiate more uh.

More of radiation!

Some new things to learn :D

~Infrared radiation is absorbed by ALL objects and surfaces.
~The absorbtion of radiant heat causes a temperature rise.

~ Infrared radiation is emmited by ALL objects and surfaces.
~ This emmision causes the temperature of the objects themselves to fall.

ALSO ALSO ALSO FURTHERMORE,
there are factors affecting the rate of infrared radiation!
They are:

1) Colour and texture and the surface
-Dull, black surfaces absorb and emmit heat much better and faster than shiny, white surfaces.

2) Surface temperature
-The higher the temperature of the surface of the object relative to the surrounding temperature, the higher the rate if infrared radiation.

3) Surface area
-If two objects have the same mass and are made of the same material, but have differetn surface areas, the object with the larger surface area will emit infrared raiation at a higher rate.

AND THAT'S THE END OF RADIATION!

Radiation/.

By now, it's like STANDARD QUESTION already. HAHA.
WHAT IS RADIATION?????

Radiation is:
- the continual emmision of infrared waves from the surface of all bodies, transmitted without the aid of a medium
(Radiation does not require a medium for energy transfer!)
*WHICH MEANS THAT RADIATION CAN EVEN TAKE PLACE IN A VACUUM*

Things to know:
1) Thermal energy from infrared waves is known as radiant heat.
2) All objects emmit radiant heat! (It's just a matter of how strong the heat is)
[The hotter the object, the greater the amount of rediant heat emmited!]

ALSO, it's interesting to know that the Sun is a major source of radiant heat!

But QUESTION: (Practice time! :D)
Why does thermal energy from the Sun reach the Earth by ONLY radiation?

MY ANWSER TO IT:
It is not possible for thermal energy from the Sun to reach the Earth through conduction or convection becasue of the vacuum existing between the Sun and the Earth. However, thermal energy from the Sun can reach the Earth through radiation as radiation does not require the thermal energy to pass through with the aid of a medium, which means that it can even take place in a vacuum.

:D

Haha Mr Lim, am I right?

:DDD

convection currents!!!

Yo all!
Today we shall focus on convection currents and its applications in this real world in real life :D

Here's a diagram which shows an example of a convection current of liquids.
(Note the direction of the arrows and blah)

Some examples of convection currents of liquids would be like when we boil water. As the next diagram shows, notice the arrows. The explanation would be that when the water is being boiled, the water at the bottom of the pot expands. the expanded water is then less dense than the surrounding water, which explains why it starts to rise. The cooler regions of the water would then sink, being denser. Hence, this movement of the liquid due to a difference in its density sets up this thing called the convection current.

As for the convection currents of air, the explanation is the same, as the air gets heated and becomes less dense than the surrounding air, it starts to rise. Also, the surrounding air which then becomes denser, starts to sink. This movement of air/gases due to a difference in its density sets up the convection current too.

Some applications and examples of the convection currents in air would be like the heater, the experiment of the spiral paper plus candle, which are shown in the diagrams below. Other examples would be like what I mentioned earlier too in my previous post in the video, about convection currents and air-balloons.

One last example that I would give would also be how convection currents are responsible for causing such a thing in nature called the sea and land breeze. (Refer to diagram below.)

More about the land and sea breeze:

During the day, land heats faster than water, so the air over the land becomes warmer and less dense. It rises and is replaced by cooler, denser air flowing in from over the water. This causes an onshore wind, called a sea breeze. Conversely, at night land cools faster than water, as does the corresponding air.

In this case, the warmer air over the water rises and is replaced by the cooler, denser air from the land, creating an offshore wind called a land breeze. This reverses the local wind circulation pattern. Convective currents can occur anywhere there is an uneven heating of the Earth´s surface.

Alrighty then :)

Although there are still SO MANY other examples of convection currents in our daily lives, but I guess I'll have to end here for convection, there's just too much to say :D

Convection video!

Haha here's a cute and funny video on convection.

Anyways in this video, as you watch it,
you will notice that the convection currents for both liquids and gases were shown.

Also, from this video, I have learnt where convection comes about in our lives,
and also how it can be applied, which I find rather cool.

The hot dog example and the heaters in the house example stated in the video are examples of how people make use of convection to help us in our lives :D
Also, I never knew that hot air balloons had something to do with convection! :D
Haha, how interesting right?

Here's the video, enjoy!

IT'S CONVECTION WEEK AHA;

Howdy peeps!
We have started on a new section of this chapter.
And its CONVECTION.
Say it with me, CONVECTIONNNNNNNN :D:D

The usual question:
WHAT IS CONVECTION.
What is it? Huh huh huh?
Well well well,

C-O-N-V-E-C-T-I-O-N is:
- another process of thermal energy transfer
- the transfer of thermal energy by means of currents in a fluid (liquid or gas)

Next, another important thing that we have to note is that there's this thing called convection currents!

A CONVECTION CURRENT is none other than the movement of fluid caused by the change in density in various parts of the fluid.

Yeahhh.
Okay I'll end off here for today.
Simple and easy :))

Oh but one last thing to note,
VERY VERY VERY SUPER DUPER UBER IMPORTANT ONE,
MUST MUST MUST ALWAYS REMEMBER,
CANNOT EVER FORGET,
that convection currents only occur in fluids such as liquids and gases but not in solids!

Wanna know why? :D
Its because convection involves the bulk movement of fluids which carry thermal energy with them.
As for solids, remember that thermal energy is transfered from one particle to another through vibrations? (Memory refresh!) :D
There is no bulk movement of the particles itself. For solids I mean.
So yeah, that's why!

EVEN MORE conduction!

Haha still haven't finished on conduction!
Anyways, this is the last part :D

CONDUCTION IN LIQUIDS AND GASES.

In liquids and gases,

thermal conduction can also take place. (from a hotter to a cooler region)
BUT. Only thing is that, the process is inefficient.
Meaning what?

As what we have studies in the other physics chapter on kinetic particles and theory,
we have learnt that the particles in liquid and gases are further apart, compared to those in solids, so...
Collisions between molecules are less frequent in liquids and even less frequent in gases, therefore...
the transfer of kinetic energy from fast moving molecules to neighbouring moelcules is slower!

GET IT GET IT GET IT? :D:D:D
Well I get it! :DD
This would explain why air is a poorer conductor of heat compared to water and also that water is a poor conductor of heat compared to solids!

OH YAY OH YAY OH YAYYYYYYY.
And this wraps up all of conduction! (;

Conduction video!

Oh yeah and I nearly forgot, haha.
Wanted to share a super cute and useful video that I found on CONDUCTION! :D
So here it is:

MORE CONDUCTION YO!

Haha the last time I ended off I didn't exactly finish about conduction, so I shall continue :D

Anyways before we procede,
here's a sample question to try! :L
To test what we've learnt from the last post :DDD

Q: Why is the rate of thermal energy transfer much faster in copper than in wood?
My Ans: Hmm, because.. Copper is a much better conductor of heat compared to wood and both conductors and insulators have different mechanisms to transfer thermal energy!

Haha yup.
Oh and another thing to note too is that, good conductors of thermal energy are usually good conductors of electricity too! Yep.

K, so now, we can move on :D
Right, so, HOW DOES CONDUCTION WORK???

Well, the explanation goes like this:
~ All solids are made up of tiny particles (atoms and molecules)
~ Thermal energy is supplied to the solid
~ the particles (atoms and molecules) at the hot end vibrate vigourously
~ These particles collide with neighbouring particles
~ Nieghbouring particles vibrate as well
~ Kinetic enery of vibrating particles at hot end transfered to neighbouring particles too

However, one thing to note would be that:
METALS contain many free electrons which move randomly between the atoms or molecules.
NON-METALS however, do not have such free electrons.

Bearing in mind this difference,
and back to what I was explaining,

So for both metals and non-metals, the particles are vibrating about their fixed positions, and this process of thermal energy transfer by conduction from the hot end to the cold end is by atomic or molecular vibrations. This process is rather slow as there is no transfer of particles.

As for metals, because of the free electrons that they have, a much faster mechanism of thermal energy transfer called free electron diffusion can take place at the same time, which explains why metals conduct heat much faster and are good conductors of heat compared to non metals.

The free electron diffusion process goes like this:
~ Metal is heated
~ free electrons in the metal gain kinetic energy and move faster
~ fast-moving electrons then diffuse and spread into the cooler parts of the metal
~ fast moving electrons collide with the atoms in the cooler parts of the metal and then transfer the kinetic energy to them
(free electrons are moving from hot end to cold end)

Which ultimately speeds up the whole process of the energy transfer.

TODAY IS CONDUCTION DAY.

Read the title.

Today, i'm gonna talk all about conduction.

CONDUCTION CONDUCTION CONDUCTION CONDUCTION CONDUCTION CONDUCTION CONDUCTION CONDUCTION

CONDUCTION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

So, important question.

WHAT IS CONDUCTION??!

Here's a few definitions, conduction is:

- the energy transfer that is mostly best in solids

(This is because liquids and gases are poor conductors of heat, compared to solids)

- the transfer of thermal energy through a medium, without the medium moving

- the process of thermal energy transfer without any flow of the material medium

They actually all mean the same thing, but just can be expressed in many different ways :D

An example of comduction in solids would be this:

As you can see from the image above, as the wax on the rod melts, the thumbtacks fall off . This is because thermal energy is transfered from the flame (hotter region) towards the cooler end of the rod (cooler region). From here we can also prove another point that it is indeed true that thermal energy flows through the material of the rod without any flow of the material itself.

As for this image above, you can see that there are 3 rods, and they all have wax at the ends of the rods. An experiment was actually carried out and certain waxes actually melted and dropped off first. This was because each rod was made out of a different material. This can let us conclude that different materials conduct heat at different rates.

In general:

Good conductors of heat would be metals, such as copper, silver, steel and iron.

Insulators of heat or bad conductors would be non metals such as plastic, wood, glass, brick, air, water and wood.

HOW HOW HOW

Today, I shall talk about something really light and easy to remember. OH YAY!

Okay, did you guys ever realize like for example, when you stand near the berbecue pit, or when you stand in front of the iron, when you are cooking/boiling something or even like when your brother is bathing and you enter the toilet and you can feel hot the steam rising up? And isn't it amazing that even though you're not in direct contact with it, like take hot water for an examnple, you are still able to feel the heat?

How could this possibly be explained!

Well, it all links back to the transfer of thermal energy, but how?

How is thermal energy transfered? - you may ask.

Today, what we're gonna learn is mainy about these 3 processes, conduction, convection and radiation!

I won't go into much detail for today, but today's homework would just be to remember the 3 different processes of thermal energy transfer, yeah? :)

Haha, oh and just one last thing that I wanted to say,

you know, these ways of thermal energy transfer can also be applied to animals!

How interesting, yeah? :D

Seriously, believe it or not.

Cool right! Haha.

Example, a bird can reduce the thermal energy transfer from its body during cold weather by fluffing up its feathers.

An African elephant can cool off quickly in hot weather because it has big ears that provide a large surface area for thermal energy transfer too.

Also, polars bears and penguins, they all each have their own special features, adaptations and ways to keep themselvews warm in the cold.




But how?
In each of these different cases, what processes of thermal energy transfer can be seen? Are they radiation, convection or conduction?

How can it be applied to those animals?

Haha, think about it!

And I'll leave you with that :)

What causes it?

Hey!
Today I'll be sharing more about the transfer of thermal energy.
Like I promised.

Anyways, as you can see from the title,
today I'll be talking about the CAUSES of thermal energy!
What causes this transfer?
Aren't you all curious! :D

Firstly, some key points about the transfer of thermal energy that we need to know:

1) Thermal energy is transfered only when there is a difference in temperature.
2) Thermal energy always flows from a region of higher temperature to a region of lower temperature.

These 2 facts can be proved by a simple experiment.

The set up would be:
Prepare 3 small basins of water of 3 different temperatures. One basin with hot water, maybe of 50degrees celcius, another one at body temperature, about 37degrees celcius and another with cold water, maybe about 10degrees celcius. We shall label these basins A, B and C respectively. Next, place your right hand in basin C, with the cold water while also placing your left hand in Basin A, the basin of hot water, at the same time. You would come to realize that you left hand would feel hot in the hot water, while your right hand would feel cold in the cold water. After a while, remove both hands, dry them with a cloth and then wait for the effects of hotness and coldness in your hands to subside. Then, place one hand, any hand, into Basin B. Your hand would feel neither hot or cold. (37degrees celcius is body temperature)

Why is this so?

This simple experiment proves the 2 key points of the transfer of thermal energy so well.

Point 1 is proven, as from this simple experiment, it is clearly shown that is it possible to feel whether you hands are feeling hot or cold as there is a temperature difference.

Point 2 is also proven in this experiment as your left hand only feels hot because it gains thermal energy from the hot water in Basin A; and your right hand feels cold because it loses thermal energy to the cold water in Basin C.

Also, from the experiment, we can also learn another thing about the transfer of thermal energy, which would be about THERMAL EQUILIBRIUM.

Which brings us to this point:
3) When a thermal equilibrium is reached between two bodies, meaning that both bodies are of the same temperature, there is no net flow of thermal energy between them.

We can see that this point is true when your hands feel neither hot or cold in Basin B, where the temperature of the water is the same as body temperature. Here, thermal equilibrium is reached as there is no net gain or loss of thermal energy between the water in Basin B and your hands.

Which ends of this part about the causes of thermal energy (:

To start of this wonderful chapter!

Hey hey all! :D
Welcome to Melodi's wonderful Physics blog! :DDD
Anyways, so here I shall do my physics project :)

So let me start of with this:

Firstly, what exactly is thermal energy?

If you would ask me, from what I know, I would say that thermal energy is equals to heat and heat is a form of energy! (Which is correct.) :D

Haha yup. I shall end off here for now.
Today we have learnt something simple, what thermal energy is.
In the next post I'll be talking more about the transfer of thermal energy! YAY ;D
More physics tomorrow people!