experiment#5 by bayot,lim,uy

7/28/2019 Experiment#5 by Bayot,Lim,Uy

http://slidepdf.com/reader/full/experiment5-by-bayotlimuy 1/16

De La Salle University

College of Education

Science Education DepartmentPHY 583M – Earth and Environmental Science

Experiment # 5METHODS OF HEAT TRANSFER

PART I HEAT TRANSFER BY CONDUCTIONPART II HEAT TRANSFER BY RADIATION

Members: Bayot, Joysol

Lim, Perlita

Uy, Roxanne

Prof: Dr. Cecil Galvez

Class Period: Sat, 8:00 am – 11:00 am

Date performed: 4/6/13

Date submitted: 4/13/13



PART I HEAT TRANSFER BY CONDUCTION

I. INTRODUCTION

A. BACKGROUND INFORMATION/THEORY AND CONCEPTS

Thermal energy transfer occurs between two substances, whenever there is a temperaturedifference between them. The process of thermal energy transfer from one substance to

another by direct contact is know and conduction. During this process, thermal energy is

transferred from a warmer substance to a cooler substance. Thermal energy transfer is

dependent on the conductivity of the substance. Thermal conductivity is a measure of

how fast thermal energy moves within a substance.

Solids are the best conductors of heat, and among solids, metals conduct heat the best.

But metals differ in their conductivity-silver is a very good conductor; copper and

aluminium are good conductors; iron and lead are poor conductors.

In this experiment two metals will be tested experimented in order to determine their

thermal conductivity.

B. OBJECTIVES

This activity aims:

To determine how the type of material can affect conductivity of an object.

To determine which type of metal will conduct thermal energy from one end to

the other more rapidly.

C. HYPOTHESIS

Aluminum will conduct thermal energy faster than brass



II. METHOD

START

SECURE MATERIALS

PREPARE SET-UP

USE DATA STUDIO PROGRAM

ARRANGE SET UP ACCORDING TO THE DIAGRAM

ATTACH USB LINKS TO COMPUTER AND OPEN

DATA STUDIO SOFTWARE

DETERMINE WHICH METAL REPRENTS THE

AUMINUM AND THE BRASS

CLEAR ALL DATA FOR DATA STUDIO

START DATA ATUDIO AND GET INITIAL

TEMPERATURE OF THE METAL ROD

TURN ON THE SOLDERING IRON

A

A

OBSERVE TEMPERATURE CHANGE FOR 15

MINUNTES

IS IT 15

MINUTES N

ALREADY?

Y

STOP RECORDING OF DATA

GET FINAL TEMPERATURE

IS THE DATA

COMPLETE

AND N

ACCURATE?

Y

FIX SET UP

END



III. Materials Used and experimental set-up

USB Link

2 PASPORT Temperature Sensors Buret clamps Soldering iron

2 different metal rods with the same dimension



IV. DATA

a. OBSERVATIONS in a DATA TABLE or CHART

metal Starting

Temp.

(0C)

Ending

Temp.

(0C)

Time to

Final temp.

(s)

Slope of

the Line

aluminium 25.1 49.6 900 0.0329

brass 25.5 35.2 900 0.0127

Table 1 .Shows the starting temperature, ending temperature, time to final temperature, and

slope of the line for both aluminium and brass

b. GRAPHS

Figure 1. Temperature against time of aluminium and brass



Figure 2. Temperature against time of aluminium and brass with linear fit data

c.

CALCULATIONS

m= y2 – y1

x2 – x1

whereinm = slope

y = change in temperature

x= change in time

V. ANALYSIS

Base from table 1, starting temperature is almost the same- 25.10C for aluminum while

25.10C for brass. The ending temperature, however, changed significantly- 49.6

0C for

aluminum while 35.2 for brass. Slope of both metals is also is significant- 0.0329 for

aluminum and brass has 0.0127.



VI. CONCLUSION

Aluminum heats up faster than brass because it has a higher thermal conductivity value

than brass. Aluminum has a thermal conductivity of 0.57 cal/cm.s.0C while brass has a

thermal conductivity of 0.31 cal/cm.s.0C.

VII. ANSWERS TO QUESTIONS

1. Was your prediction correct?

Yes, aluminium conducts heat faster than brass

2. How do you know the metal cylinders conducted heat energy?

Heat is the byproduct of an object vibrating at the molecular level. When those vibrationstransmit to nearby collision molecules, heat transfer occurs. Generally, the less a metal

weighs, the quicker it can transfer heat.

3. Which metal conducted heat energy the fastest? Explain using the slope dataAluminum conducts heat energy the fastest. It is less dense than brass, so has less mass

per volume to absorb heat energy. For the same amount of heat energy put into the same

volume of aluminum and brass, the aluminum will increase in temperature faster since

there is less mass to heat up. This is also known as thermal inertia. Aluminum has lessthermal inertia than brass. Their slope also defines heat energy transfer. The larger the

slope, the faster it conducts heat energy, in this case aluminum has a slope of 0.0329while brass has only 0.0127.

VIII. REFERENCES

1. Williams, Trinklein, Metcalfe. Modern Physics, 1 st

edition.1984

2. Cordero-Navaza and Valdes. Physics, 2nd

edition. 2001

3. Hewitt. Conceptual Physics. 2005



PART II HEAT TRANSFER BY RADIATION

I. INTRODUCTION

A. BACKGROUND INFORMATION/THEORY AND CONCEPTS

Radiation (radiant energy) is the transfer of energy by invisible waves given off by theenergy source. Heat from the sun travels through space by radiation. This form of heat,

radiant heat, is thought to be produced by the internal vibration of the particles that make

up a body that is the source of heat (like the sun), and moves through space in the form of

a wave. Radiant heat is only one of the many forms of electromagnetic waves.

Color affects the amount of radiant heat absorbed by an object. Black or darkened

surfaces absorb heat faster than white or light-colored ones.

In this experiment a black painted can’s tem perature change will be compared with an

unpainted can if exposed to the same amount of heat.

B. OBJECTIVES

This activity aims:

To determine how colour effects radiant energy transfer.

To compare temperature change between a painted and an unpainted can by

means of radiation

C. HYPOTHESIS

Painted can will heat up more than the unpainted can



II. METHOD

START

SECURE MATERIALS

PREPARE SET-UP

USE DATA STUDIO PROGRAM

ARRANGE SET UP –heat lamp is about 20 cm. in

front of the 2 cans

ATTACH USB LINKS TO COMPUTER AND OPEN

DATA STUDIO SOFTWARE

DETERMINE WHICH METAL REPRENTS THE

PAINTED AND THE UNPAINTED CAN

CLEAR ALL DATA FOR DATA STUDIO

START DATA STUDIO AND GET INITIAL

TEMPERATURE OF THE CANS

OBSERVE TEMPERATURE CHANGE FOR 15 MINUNTES

A

A

IS IT 15

MINUTES N

ALREADY?

Y

STOP RECORDING OF DATA

GET FINAL TEMPERATURE

IS THE DATA

COMPLETE

AND N

ACCURATE?

Y

FIX SET UP

END



III. Materials Used and experimental set-up

USB Link

2 PASPORT Temperature Sensors

2 radiation cans painted black and silver

150 Watts lamp



IV. DATA

a. OBSERVATIONS in a DATA TABLE or CHART

Painted Can

(0C)

Unpainted Can

(0C)

Starting Temp. 25.8 25.7

Ending Temp. 31.7 27.3

Change in Temp. 5.9 1.6

Table 1.Shows the comparison of absorption of radiation of a painted (black) versus an

unpainted can

b. GRAPHS

Figure 1. Temperature against time of the painted (black) and unpainted (light) can



Figure 2. Temperature against time of the painted (black) and unpainted (light) can with

linear fit data

c. CALCULATIONS

Change in Temperature = Starting Temperature- Ending Temperature

V. ANALYSIS

Base from table 1 it shows the starting, ending and change in temperature for the painted

and unpainted can. The painted can has almost the same starting temperature of 25.80C

with the unpainted can, which was 25.70C. However Their ending temperature has a

significant change- The painted can’s temperature raised to 31.7 0C while the unpainted

can has only raised to 27.30C. The change in temperature is 5.9 for the painted can while

1.6 only for the unpainted can. This shows that through radiation, the black can absorbed

more heat efficiently.



VI. CONCLUSION

Dark colored materials will absorb more heat than light colored materials.

VII. ANSWERS TO QUESTIONS

1. Suppose you had to choose a roof color for a new house and were given two choices:

dark grey or light grey. Which would you choose to keep your house cooler in the

summer? Why?

One should choose the light grey color. Light colors reflect heat and sunlight; whereas

dark colors absorb heat and light. Buildings are similar to people. If one has a dark-

colored roof, one’s building will be hotter than if it had a light-colored roof. This sameroof, on a clear, cool night will transmit more heat from the house than would a light

colored roof. A white or nearly white roof will reflect solar radiation during the day andwill not radiate much heat at night.

2. Why does an asphalt parking lot feel hotter in the summer than an adjacent grassy

area?

Asphalt is very "dark" in color. Things that appear dark in color reflect much less visible

light than those that are light. Instead of reflecting all that light, it is absorbed. Being

absorbed means that when the energy from the light strikes the molecules it causes the

atoms to vibrate. This vibration is heat. This heat then radiates to the ambient air around

it, causing it to also be much warmer. Grass is "bright" in color.

Grass has large quantities of water in it, which constantly is being converted and

evaporated. The act of evaporating water requires heat, so it "sucks" the heat out of the

grass. That heat does then go into the surrounding area, but to remain a gas, the water

must hold onto it, and because of it's low density the water vapor rises away from the

ground, both things decreasing the ambient air temperature.

Grass also directly uses the energy provided by the light to break apart and recombine

molecules from water, air and other sources for life and growth. Think of it as "eating"

what is around it. This process is called photosynthesis



VIII. REFERENCES

1. Williams, Trinklein, Metcalfe. Modern Physics, 1 st

edition.1984

2. Cordero-Navaza and Valdes. Physics, 2nd

edition. 20013. Hewitt. Conceptual Physics. 2005

experiment#5 by bayot,lim,uy

Documents