KULIAH 8

Pokok Bahasan : TERMOFISIKA

Sub Bahasan : Fenomena Alam (Pengertian Dasar)

* Konsep suhu secara mikroskopis (Teori Kinetik Gas)

Alat ukur suhu (Kesetimbangan Termal)

Kalor (transfer energi karena perbedaan suhu benda)

Tujuan Pembelajaran, mahasiswa mampu- memerikan (describes) fenomena alam yang berhubungan dengan termofisika

- menjelaskan kembali pengertian-pengertian dasar termofisika

- menjelaskan kembali konsep suhu secara mikroskopis

PUSTAKA RUJUKAN

I. Fenomena Alam/keseharian: Termofisika

Some applications related to Gas Phenomenon

Mesin motor 4 Tak (4 stroke)http://rembhol.blogspot.com/2009_08_01_archive.html

Camshaft

16 valves

Kesehatan cuaca

Interaksi “Organisme Berdarah-panas” terhadap lingkungan berbasis kalor

Termofisika: Pengantar ke teori kinetik gas

TAUTAN PEMBELAJARAN TERMOFISIKA

Celcius-FahrenheitoF = (9/5).oC +

32Prinsip: Kesetimbangan suhu/termalperlu waktu sesaat agar dua bendaberbeda suhu, setara suhunya

oC = (5/9) (oF − 32)

Reamur

Termometer

Kelvin (absolut)K = oC + 273,15

rapat/tidaknya atom, menentukanmudah/tidaknya benda SUHU

Ukuran (kuantitas) panas/dingin benda

rapat/tidaknya atom:→ massa benda

mudah/tidaknya benda menjadi panas/dingin →

secara mikro, semua materitersusun atas atomPanas/Dingin?

Sensasi yang dirasa

TErMos?

Jumlah kalor Q yang terkandung dalammassa m benda untuk menaikkan suhu benda → Q = m.c.Δt

Fisika: Mengukur / Menghitung!

Saat dua benda (m1 & m2 ) berbeda suhudikontakkan, akan terjadi perpindahan kalor

KALOR dapat diubah menjadi ENERGI(tara kalor mekanik)

1 kalori = 4,186 joule1 joule = 0,239 kalori

Q-1in = Q-2out

saat

tm1 <

tm1Kalor dapat berpindah di dalam sistematau antar sistem-lingkungan (mekanisme perpindahahan kalor) antar sistem-lingkungan

inter sistem

antar sistem-lingkungan

RADIASIKONVEK

SIKONDUKSI

TERMO-FISIKA

THERMAL EXPANSIONPemuaian benda padat/gas akibat perubahan suhu

body's metabolism :sweating, prespiration

constant pressure, Gay Lussac's lawconstant temperature, Boyle's law

varied pressure, temperature & volume, Boyle-Gay Lussac's law

expansion of gaseous

phase changeobje absorbed

&solute sensation

ofexpansion

having temperature

thermal condition differenc

es heat, Q

hot/cold

two objects havingtemperatureis quantized

adifferences and in

expansion contact each

othertransfer

mechanis

temperature

measured using

thermometer

Black's principle1D, linier (α)

2D, area (β)

3D, volume

(γ) conversion radiati

onscale (unit) conversion

body's metabolism :sweating, prespiration

conduction

released heat

s

heat

solid object heate

d

II. TEMPERATURE: Kinetic Theory of Gases

“optional”

Gas Ideal

Five (5) assumptions of kinetic molecular theory of gas

(Ideal) Gas - An atomic view of thermal energy and temperatureImaginary gas that perfectly fits all the assumptions of the kinetic molecular theory .

http://kaffee.50webs.com/Science/activities/Chem/Activity.Gas_Laws.PSet1.html

1. Gases made of tiny particles far apart relative to their size.

2. Collisions between gas particles and between particles and container walls are elastic collisions. (elastic collisions = one in which there is no net loss of kinetic energy)

3. Gas particles are in continuous random motion . 4. There are no forces of attraction or repulsion between

gas particles . 5. The average kinetic energy of gas particles depends

on the temperature of the gas.

All gases at the same temperature have the same average kinetic energy. Thus, the smaller mass particles-have higher velocity .

http://physicsed.buffalostate.edu/Wiley/CJ6e/links14.html

http://whs.wsd.wednet.edu/Faculty/Busse/MathHomePage/busseclasses/apphysics/studyguides/chapter11_2008/Chapter11StudyGuide2008.html

http://www.astarmathsandphysics.com/a_level_physics_notes/thermal_physics_and_gases/a_level_physics_notes_kinetic_theory_of_gases.html

http://quantumfreak.com/derivation-of-pvnrt-the-equation-of-ideal-gas/

Consider a rectangular box with length L, areas of ends A1 and A2. There is a single molecule with speed vx traveling left and right to the end of the box by colliding with the end walls.

The time between collisions with the wall is the distance of travel between wall collisions divided by the speed.

1.

The frequency of collisions with the wall in collisions per second is

2.

According to Newton, force is the time rate of change of the momentum

3.

The momentum change is equal to the momentum after collision minus the momentum before collision. Since we consider the momentum after collision to be mv, the momentum before collision should be in opposite direction and therefore equal to -mv.

4.

According to equation #3, force is the change in momentum divided by change in time .  To get an equation of average force in term of particle velocity , we take change in momemtum multiply by the frequency from equation #2. 

5.

The pressure, P, exerted by a single molecule is the average force per unit area, A. Also V=AL which is the volume of the rectangular box.

6.

Let’s say that we have N molecules of gas traveling on the x-axis. The pressure will be

7.

To simplify the situation we will take the mean square speed of N number of molecules instead of summing up individual molecules. Therefore, equation #7 will become

8. 

Earlier we are trying to simplify the situation by only considering that a molecule with mass m is traveling on the x axis.  However, the real world is much more complicated than that. To make a more accurate derivation we need to account all 3 possible components of the particle’s speed, vx, vy and vz.

9.

Since there are a large number of molecules we can assume that there are equal numbers of molecules moving in each of co-ordinate directions.

10.

Because the molecules are free too move in three dimensions, they will hit the walls in one of the three dimensions one third as often. Our final pressure equation becomes 

11.

However to simplify the equation further, we define the temperature, T, as a measure of thermal motion of gas particles because temperature is much easier to measure than the speed of the particle. The only energy involve in this model is kinetic energy and this kinetic enery is proportional to the temperature T. 

12.

To combine the equation #11 and #12 we solve kinetic energy equation #12 for mv2. 

13.

Since the temperature can be obtained easily with simple daily measurement like a thermometer, we will now replace the result of kinetic equation #13 with with a constant R times the temperature, T. Again, since T is proportional to the kinentic energy it is logical to say that T times k is equal to the kinetic energy E. k, however, will currently remains unknown.

14.

Combining equation #14 with #11, we get:

15.

Because a molecule is too small and therefore impractical we will take the number of molecules, N and divide it by the Avogadro’s number, NA= 6.0221 x 1023/mol to get n (the number of moles)

16.

Since N is divided by Na, k must be multiply by Na to preserve the original equation. Therefore, the constant R is created.

17.

Now we can achieve the final equation by replacing N (number of melecules) with n (number of moles) and k with R. 

17.

Calculation of R & k

According to numerous tests and observations, one mole of gas is a 22.4 liter vessel at 273K exerts a pressure of 1.00 atmosphere (atm). From the ideal gas equation above:

A.

B.

C.

Deskripsi fisika mengenai gas

Keterhubungan temperatur dengan Energi Kinetik atom dan molekul-molekul gas

1. Temperature DomainThe temperature of an ideal gas is a measure of the average kinetic energy of the atoms that make up the gas

rms speed and temperature

Thermal Energy is directly proportional to temperature.

2. Temperature-Volume Domain

Jacques Charles (1878)

3. Pressure-Volume Domain (Boyle’s Law)

Robert Boyle

4. Pressure-Temperature Domain (GayLussac’s Law)

Joseph Louis Gay-Lussac (1802)

http://www.oswego.edu/~kanbur/a100/lecture10.html

http://cfbt-us.com/wordpress/?cat=5

Review Keterhubungan temperatur dengan Energi Kinetik atom dan molekul-molekul gas

http://reich-chemistry.wikispaces.com/J.+Brock+Gas+Laws

Ideal Gas Math Description (pressure X volume = mass X constant R X temperature).

Latihan soal Teori Kinetik GasBefore going to some sample problems, let's be very clear: EVERY TEMPERATURE USED IN A CALCULATION MUST BE IN KELVINS, NOT DEGREES CELSIUS.

Example #1: A gas is collected and found to fill 2.85 L at 25.0°C. What will be its volume at standard temperature? Solution: Convert 25.0°C t Kelvin and you get 298 K. Standard temperature in like this:

Remember that you have to plug into the equation in a very specific way. The temperatures and volumesand

Example #2: 4.40 L of a gas is collected at 50.0°C. What will be its volume upon cooling to 25.0°C? First of all, 2.20 L is the wrong answer. Sometimes a student will look at the temperature being cut in half and reason that the volume must also be cut in half. That would be true if the temperature was in Kelvin. However, in this problem the Celsius is cut in half, not the Kelvin. Solution:rt 50.0°C to 323 K and 25.0°C to 298 K. Then plug into the equation and solve for x, like this:

Example #3: 5.00 L of a gas is collected at 100 K and then allowed to expand to 20.0 L. What must the new temperature be in order to maintain the same pressure (as required by Charles' Law)? Answer:

Example #4: a 2.5 liter sample of gas is at STP. When the temperature is raised to 273°C and the pressure remains constant, what is the new volume?

Example #5: An ideal gas at 7.00 °C is in a spherical flexible container having a radius of 1.18 cm. The gas is heated at constant pressure to 88.0 °C. Determine the radius of the spherical container after the gas is heated. [Volume of a sphere = (4/3)πr3] oblem.

For reference use, room temperature is set to be 25oC

TERMOFISIKAPanas / Dingin (benda)panas dan dingin adalah sifat termal alami sebuah benda

panas dan dingin hanya sensasi yang dapat dirasakan melalui indra peraba (mostly)

seberapa panas atau dinginya benda dinyatakan dengan istilah temperatur/suhu(temperature is quantification of how hot or cold an object is)

Alat Ukur Suhu

Thermometers are devices used to measure the temperature of an object or a system

• Celsius scale : Temp. of ice–water (water–steam) mixture defined as 0°C (100°C)

– Freezing point vs. boiling point of water

– Distance between these 2 points divided into 100 equal segments

• Fahrenheit scale: Most common scale used in the U.S.

– Employs a smaller degree than Celsius scale

– Uses a different zero of temperature than Celsius scale

Temperature of the freezing point of water is set at 32°F Temperature of the boiling point of water is set at 212°F 180 divisions between these 2 points

Room temperature is about 20° atau 25°C, a hot summer day might be 40° C, and a cold winter day would be around -20° C.

Prinsip Pengukuran suhu/temperatur sebuah benda

Tercapai kesetimbangan suhu (thermal equilibrium) antara termometer dengan benda yang diukur suhunya (butuh waktu)

Dirujuk sebagai hukum ke-nol Termodinamika(Zeroth law came to light only in 1930s, long after 1st and 2nd laws of thermodynamics were established)

• The flow of energy that occurs between 2 objects or systems due to a temperature difference between them is called heat flow

• Objects are in thermal contact if heat flow can take place between them

• Thermal equilibrium exists when two objects in thermal contact with each other cease to exchange energy

Hukum ke-nol Termodinamika

Definition of temperature relies on the zeroth law of thermodynamics:

If objects A and B are in thermal equilibrium with a third object, C, then A and B are in thermal contact with each other

• Less formal definition: Every body has a property called temperature. When 2 bodies are in thermal equilibrium, their temperatures are equal, and vice versa

• Zeroth law used constantly in the lab– If we want to know if 2 liquids have same

temperature, we measure temperature of each with a thermometer

– No need to bring them into thermal contact

Skala Temperatur dan Rujukan Suhu Materi

The absolute-zero reference point forms basis of Kelvin temperature scale

Faktor Konversi Skala termometer

Skala temperatur dari dua termometer dapat dikonversi berdasar penetapan jangkauan nilai titik beku ke titik didih air serta selisih titik beku kedua termometer.

Misal, faktor konversi skala Celcius ke Fahrenheit.Jangkauan nilai titik beku ke titik didih Celcius

0 – 100 = 100 skalaJangkauan nilai titik beku ke titik didih Fahrenheit

32 – 212 = 180 skala

Skala titik beku celcius akan setara dengan skala titik beku fahrenheit bila dikurangi 32 skala.

Faktor konversi skala suhu termometer bersifat linier, artinya perubahan nilai dari kedua skala akan mengikuti perubahan tetap sesuai persamaan liniernya.

Latihan Bila dirancang sebuah termometer X yang memiliki skala penunjukkan titik beku air 20o dan skala penunjukkan titik didih air 90o, carilah faktor konversi termometer X terhadap skala termometer Celcius.

At what temperatures do, fahrenheit and celcius thermometer read the same scale?

fahrenheit celcius

celcius fahrenheit

kelvin celcius

* Termometer Gas

Ideally, the readings of a thermometer should not depend on material used• Gas thermometer comes close to

this ideal • Principle is that pressure of a gas at

constant volume increases with temperature

• Gas placed in constant-volume container and pressure is measured (manometer in figure above)Calibrated by measuring pressure at 2 temperatures

• Temperature readings are nearly independent of the gas

• Pressure varies with temperature when maintaining a constant volume

Pengaturan Suhu tubuh manusia

Mekanisme perpindahan kalor berpengaruh pada pengaturan suhu tubuh

http://www.colorado.edu/intphys/Class/IPHY3430-200/021metabolism-energy.htm

Secara khusus, pengaturan suhu tubuh manusia dilakukan oleh mekanisme umpan balik syaraf (pada kelenjar hypothalmus) yang kemudian disebarkan hingga ke seluruh penampang permukaan kulit.

Body and Oral Temperature

Apa yang dilakukan oleh perawat saat mengukur suhu tubuh pasiennya…?

Sensor Suhu dan respon tubuh terhadap perubahan suhu

Thermal Expansion Most objects (substances) expand when heated and contract when cooled. However, the amount of expansion or contraction varies, depending on materials and sizes. Substance itself is categorized as solid, fluid and gases.

Expansion in solid occurs in one dimension (linier), two dimension (area) and three

dimension (volume). Expansion in fluid only occurs in volume dimension. Expansion in gases, however, depends on pressure, temperature and volume.

Three types of thermal expansion in solid

Expansion in one dimension (linier) for solid (metal: ferrum, aluminium, copper)

The thermal expansion of an object is a consequence of the change in the average separation between its constituent atoms or molecules

At ordinary temperatures, molecules vibrate with a small amplitude

As temperature increases, the amplitude increases. This causes the overall object as a whole to expand

For relatively small changes in temperature, the linear dimensions of object change according to

(Coefficient of linear expansion, a, depends on the material)

in surface area

in volume ( = 2 and = 3 only if a

is the same in all directions

Latihan

The band in the figure is stainless steel (coefficient of linear expansion = 17.3 ´ 10–6 °C–1 . It is essentially circular with an initial mean radius of 5.0 mm, a height of 4.0 mm, and a thickness of 0.50 mm. If the band just fits snugly over the tooth when heated to a temperature of 80°C, what is the linier and area expansion band when it normally stored in a temperature of 20°C?

III. KALOR (Heat)

Kalor Istilah kalor diperkenalkan untuk menyatakan adanya “aliran” (yang sebenarnya merupakan bentuk energi) yang timbul manakala dua buah benda berbeda suhu dikontakkan (didekatkan secara fisik)

“aliran” dalam bentuk transfer energi panas (kalor) akan berhenti manakala suhu dua benda yang berkontak fisik terukur sama –– tercapai kesetimbangan termal.

Arah aliran kalor adalah dari benda suhu tinggi ke benda suhu rendah

Kalor Jenis menyatakan - kemampuan sebuah benda/materi/zat

dalam “menampung” kalor.- jumlah energi yang harus ditambahkan

untuk menaikkan suhu per satuan massa benda sebesar satu satuan suhu (oC atau K)

(laju memanaskan benda?)- jumlah energi yang harus dibuang untuk

menurunkan suhu per satuan massa benda sebesar satu satuan suhu

(laju mendinginkan benda?)

Jumlah kalor yang dilepaskan atau diserap oleh sebuah benda

tunggal

When an object of mass m having heated up or cooled down (i.e., experience temperature changes) then a number of heat is counted.

If heat is symbolized by Q and temperature changes is t, then heat is proportional to object’s mass and temperature changes

Q m tSome material are easily heating up and some don’t. It refers to material characteristics which is known as specific heat (c).

Total amount of heat Q required to change the temperature of and object is expressed by

Latihan If wood is easily to burn, why it used as isolator for frying pan’s handle? Explain!

Bila merujuk arah aliran kalor, mengapa tubuh yang suhu normalnya 37oC merasa seperti ‘menyerap’ kalor pada saat cuaca udara panas (32oC)…? Jelaskan

how much heat is absorbed by your body (c = 0.83 kal/kg.Co) when exposed to sunlight in a hot day (t = 32 oC). Analyze how absorbed heat could affect you

Q = m c tis amount of heat of single object due to temperature

changing

being heating up- object’s temperature

rising- heat is absorbed by the

being cooling down- object’s temperature

droping- heat is released by the

heat:

transferred energythrough temperature

difference

When you turn on the hot water to wash dishes, the water pipes have to heat up. How much heat is absorbed by a copper water pipe with a mass of 2.3 kg when its temperature is raised from 20.0oC to 80.0oC?

Q = m c t Q = (2.3kg) (390J/kgoC)(60.0oC)Q = 53820 J or 54 kJ

Hukum perpindahan Kalor (Azas Black)

Dalam sistem tertutupyaitu sistem yang di dalamnya tidak memungkinkan terjadinya perpindahan energi dari atau ke lingkunganbila dua benda yang berlainan suhu didekatkan, maka jumlah kalor yang dilepas oleh benda yang lebih tinggi suhunya sama dengan jumlah kalor yang diterima oleh benda yang lebih rendah suhunya.

Proses ini dikenal dengan nama asas black dan ditulis sebagai

Qreleased = Qabsorbed m1 c1 t = m2 c2 t

The amount of heat released by the subtance with higher temperature is equal to the amount of heat absorbed by the subtance with lower temperature.

Latihan

kesetaraan kalor mekanik(Keterkaitan Kerja dengan Kalor)

James Prescott Joule dengan percobaannya. Ia berusaha membuktikan bahwa ada keterkaitan antara energi mekanik (gerak) dengan energi termal.

Air di dalam wadah yang terus menerus diaduk (diberikan energi mekanik/gerak) lama kelamaan akan naik suhunya. Bila energi gerak dinyatakan dengan satuan joule, kenaikan suhu yang pada dasarnya menaikkan energi termal dinyatakan dengan satuan kalori, terdapat hubungan konversi

Energi mekanik berupa gerak dapat “muncul” dalam bentuk tarikan/dorongan yang berkerja pada sebuah luas penampang. Konsep ini merupakan cikal bakal lahirnya mesin

*The Experiment (bom

kalorimeter)

Latihan Seorang wanita (m = 60 kg) menyantap kue dan ice cream secara berlebihan. Ia sadar kelebihan kalori sebesar 500 kkal. Karenanya, ia ingin membuang kelebihan kalori tersebut dengan cara jogging menaiki tangga. Berapa tinggi tangga yang harus ia naiki untuk mengkompensasi (mengurangi) kelebihan kalorinya tersebut?

500 kkal dalam satuan joule setara dengan (500 kkal) x (4,186 . 103 J/kkal) = 2,09 . 106 J. Kerja yang dibutuhkan untuk menaiki tangga secara vertikal setinggi h adalah W = mgh,

Ternyata, wanita ini harus menaiki tangga setinggi gunung!(Hal ini wajar saja, karena tubuh manusia tidak mengubah energi dengan efisiensi 100%, tetapi hanya sekitar 20% saja!)

IV. PERPINDAHAN KALOR (Heat)

Mekanisme perpindahan kalor (umum)

compensation of the law of energy conservation.

conduction is heat transfer mechanism within internal object without movement of their particle's contents

condution mechanisms act upon :

(1) transfer through free electrons

(2) transfer through inter-particles collision

k = thermal conductivity (J/s.m.Co)A = cross sectional area (m2)L = distance between two ends of object (m)T = temperature difference (oC)

H = heat transfer rate Q = heat flow (J)t = time interval (s)

conduction heat tranfer rate (H) :

Latihan

Sebuah lampu pijar memancarkan energi panas dan menembus dinding kaca sebuah inkubator. Hitung laju aliran panas yang menembus kaca jika ukuran (1,0 x 0,75) m2 dan tebalnya 3,0 mm. Suhu di dalam inkubator 20oC dan di luar 25oC (k-kaca = 0,84 J/m.s.oC)

Luas kaca, A = 1,0 x 0,75 0,7 m2 Panjang lintasan penjalaran panas, l = 3,0 . 103 mBesarnya laju aliran panas adalah

Seseorang berjalan

membangkitkan kalor 0,07 kkal/s. Jika permukaan tubuhnya 1,5 m2 dan kalor dibangkitkan 0,03 m dibawah kulitnya, berapa selisih suhu antara permukaan kulit dengan bagian dalam kulit. Termal konduksi yang dibangkitkan otot

5 x 105 kkal/s.K

convection latin : com (together) + vehere (to

carry)is the process whereby heat is transferred by the mass movement of their molecules collectively

(1) natural convection

(2) forced convection

convection heat tranfer rate (H) :

H = heat transfer h = thermal convectivity (J/s.m2.Co)A = cross sectional area (m2)T = temperature difference (oC)

Test your self!(1) explain how weather change! (see figure in natural

convection)(2) explain how a refregerator and air conditioner work! ( see

figure in forced convection)(3) does it worth cooling a room by letting the refrigerator door

opened?(4) does an electric fan cool the air? why or why not? if not, why

radiation is the process of heat transnfer in the form of electromagnetic wave

As it in form of electromagnetic wave, so it doesn’t need medium to travel. The biggest radiation ever is sun light.

Normally, every objects (as it has certain temperature) are source of heat and emit radiation. This was stated by Stefan and Boltzmann.

Emission is another type of radiation: A type of heat transfer where the heat is transferred directly from the surface of an object as an infrared energy.

H = heat transfer e = emissivity ; where 0 < e < 1 = Stefan-Boltzmann constant = 5.67 . 108 W/m2.K4 A = cross sectional area (m2)T = absolute temperature

Stefan-Boltzmann's Law on Radiation

Absorption and emission of radiation (explanation of emissivity e)

Latihan Dalam laboratorium, seorang tanpa busana dengan luas permukaan badan 1,4 m2 dan emisivitas 0,85 mempunyai suhu kulit 37oC. Jika ia berdiri di tengah ruangan tertutup bersuhu 20oC, berapa banyak kalor yang hilang dari orang tersebut per menitnya?

Q = t

= 0,85(1,4)(5,67.10-8)(3104 2934)(60)= 7550 Watt

Example:  How much does the human body radiate?------------------------------------------------------------Body temperature = 37oC = 37 +273 = 310 K, Estimate surface area A = 1.5 m2        e = 0.70H = e A T4

     = (0.70)(5.67 x 10-8)(1.5 m2)(310)4

     = 550 watts (5 light bulbs)------------------------------------------------------------The sun provides 1000 W/m2 at the Earth's surface. 30 % is reflected by human skin.  700 W is absorbed per square meter.  

Test your self!(1) explain, what makes the difference between convection-

conduction and radiation processes

(2) a person seat in AC room of 20oC. If his body's area, temperature and emissivity are 2 m2, 37oC, 0.70 each and is 5.67 . 108 W/m2.K4, determine energy radiated from his body

(do you know?) The human body is a heat-generating object

*Cooling of Body (Temperature Regulation)

Hm = kalor dr metabolime (70 – 1400 kkal/h)HC = kalor hilang konveksi = 6,1 A (Ts – Ta) kkal/hHr = kalor hilang radiasi = 5,6 A (Ts – Ta) kkal/h

Hs = kalor hilang evaporasi keringat = 580r kkal/h Hl = kalor hilang evaporasi dr paru-paru = 9 kkal/h

The cooling effect of perspiration evaporation makes use of the very large heat of vaporization of water. This heat of vaporization is 540 calories/gm at the boiling point, but is even larger, 580 cal/gm, at the normal skin temperature.

Simplified model of the process by which the human body gives off heat. Even when inactive, an adult male must lose heat at a rate of about 90 watts as a result of his basal metabolism.

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/coobod.html#c1

Hm = Hc + Hr + Hs + Hl

A = luas bidang tubuhTs = suhu kulit ; Ta = suhu udarar = laju keringat (kg/h)

Infrared Thermography

Characteristics of Infrared Thermography equipment

Merits of Infrared Thermography equipment

Infrared thermography is equipment or method, which detects infrared energy emitted from object, converts it to temperature, and displays image of temperature distribution.1. It captures as a temperature distribution on a

surface,and it can display as a visible information.2. Temperature can be measured from a distance

without contacting an object.3. Temperature can be measured in real time.

1. Temperature can be measured easily for a moving object or an object which is dangerous to get close to.

2. Temperature of small object can be measured without confusing the temperature.

3. Temperature of food, medicine or chemicals can be measured in a sanitary fashion.

4. Temperature of an object with drastic temperature change or a phenomenon during a short period of time can be measured.

Principle of measurement by Infrared Thermography equipment

Uses of Thermographyhttp://www.infracam.co.nz/aboutinfrared.php

Efficiency Human body as a machine

The efficiency of the human body is the ratio between the work rate and the metabolic rate

The metabolic rate is related to the rate at which work is done and heat if transferred

Entropy

*Human Metabolism (Thermodynamic’s Laws)

Thermo-genesis, (thermo = heat and genesis = creation) which is a rise in your body temperature and a temporary way to increase the rate at which our body burn calories.

basal metabolic rate (bmr) is the daily rate of energy consumption while resting but awake

There are a number of things we can do that can bring about thermogenesis and a temporarily speeded up metabolism.

Whenever you eat anything, the process of digestion temporarily raises your body temperature as it sets about digesting that food.

Drinking a glass of cold water will temporarily cause thermogenesis for a short while before falling off again.

Being active or doing exericise also means that the heat generated by your body rises and will then slowly abate again.

Entropy (S) is a measure of the state of disorder of a system

The change in Entropy (S) of a system between two equilibrium states is given by the energy transferred in a reversible path divided by the absolute temperature T of the system in this interval

ΔS = Qr

Second law of thermodynamic s : the entropy of the universe increases in all natural processes.

T