effects of varying points of heat application to ice at confined volume

7/29/2019 Effects of Varying Points of Heat Application to Ice at Confined Volume

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Effect of varying points of

heat application on the timefor phase change of solid to

liquid H20ANDRES, Marc Louis 1

ARMENDEZ, Kevin Jhon Paul1GUNGON, Ma. Paulina1

MACALE, Genesis1

1Institute of Civil Engineering, University of the PhilippinesDiliman


2/15

Abstract

This experiment involves the investigation of themelting time and behavior of ice in a confined volumesubjected to convective heat transfer at varying points.

The aspects explored in the experiment are the relationship

of the point of application of heat to the ice-to-water phasechange in a confined volume, the total time needed forcomplete ice-to-water phase change, and possible factorsthat affects melting of ice. Upon completion of theexperiment, we found the most efficient method of melting

ice in confined volume that can be used not only forexperimental purposes but also for practical purposes.


3/15

Introduction

Heat convection in fluids is an essential conceptin thermodynamics.

Convection is heat transfer by motion offluid particles such as air or water whenthe heated fluid is caused to move away

from the source of heat.


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Introduction

By convection, heated water expands andbecomes more buoyant. Cooler, more densewater near the surface descends and patterns ofcirculation can be formed.

HEAT

The time it takes tocomplete a phasechange of a body

subjected toconvection is ofinterest in this

investigative report.


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Methodology

3 (6 inch)Test tubes

ElectricStove

Ruler2 Digitalthermometer 2 Iron clamp

stands

TimerSteamGenerator

Materials


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Methodology

1

Before actual experiment, prepare 3 test tubes with equal amounts ofwater and let it freeze.

2

Heat the bottom of the test tube with the steam from the steam

generator.

3

For every elapsed minute, monitor the actual temperature of thesteam and the ice-water surface of the test tube simultaneously.

4 Record the time it takes for the ice to melt completely

5

Repeat steps 2-4, but instead of heating the bottom of the test tube, doit at a height of4cm & 8cm from the bottom of the test tube.

Procedure


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Methodology

Materials and

Set-up

Ice melting

(bottom)

Ice melting

(4cm)

Ice melting

(8cm)


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0

20

40

60

80

100

120

0 0.5 1 1.5 2 2.5 3 3.5

Temperature

(Celsius)

Time (minutes)

Results and Discussion

R = 0.950

-20

0

20

40

60

80

100

120

0 2 4 6 8

Temperature(Celsius)

Time (minutes)

R = 1

-20

0

20

40

60

80

100

120

0 1 2 3 4 5

Temperature(C

elsius)

Time (minutes)

LEGEND:Green Dots Temperature of Steam

Blue Dots - Temperature at the

water/ice surface

Test tube heated at the bottom

Test tube heated 4cm from the bottom Test tube heated 8cm from the bottom

Temperature vs. Time


9/15


Based from the experiment, it showed that higher point ofapplication of heat requires shorter time for the ice to

completely change its phase from ice to water.

POINT OF APPLICATION TIME IT TOOK FOR TOTALPHASE CHANGE OF ICE TO

WATER

BOTTOM 7 Minutes : 17.50 Seconds

4 CM FROM THE BOTTOM 4 Minutes : 41.45 Seconds

8 CM FROM THE BOTTOM 3 Minutes : 49.63 Seconds


10/15

Results and DiscussionStated earlier, less dense particles tends to stay on top of the fluid

while the denser settles at the bottom. Based from the table below, itshows that (pure) water was most dense at 4 degrees Celsius andleast dense at its solid state (ice).

Temp

( C )

Density

pure

water

( g/cm3 )

Density

pure water

( kg/m3 )

Density

tap

water

( g/cm3 )

Density

pure

water

lb/cu.ft

0 (solid) 0.9150 915.0 - -

0 (liquid) 0.9999 999.9 0.99987 62.42

4 1.0000 1000 0.99999 62.42

20 0.9982 998.2 0.99823 62.28

40 0.9922 992.2 0.99225 61.92

60 0.9832 983.2 0.98389 61.39

80 0.9718 971.8 0.97487 60.65

Table of Density of Pure & Tap* Water


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HEAT

Since ice was less dense compared to

liquid water at any temperature, it tendsto remain on top when the test tube washeated at the bottom. Doing so wouldmelt the ice at bottom of the test tube but

the top portion of the test tube wouldremain as ice.

HEAT

Thus, one way for the applied heat at the

bottom to melt the ice is throughconvection.



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HEAT

When the ice is heated somewhere in

the middle, it melts that part. Thisheated part will tend move to the top

of the test tube thus heating and

melting the ice on top.

HEAT


On the other part, (after melting

of the ice on top) the ice at the

bottom tends to move upwardsdue to its low density and will

now be subjected to the applied

heat and then melt.


13/15

ConclusionThe Ice case

In confined volume, melting of ice-to-water convention occurs fasterat higher elevation

Point of contact of ice to the heating medium

Buoyancy serves as a catalyst for better elevated melting

Practical example: Fastfood Softdrinks with ice

W

AT

E

R

FAST

W

A

T

E

R

FASTER!


14/15

Acknowledgement

We would like to acknowledge our deepest thanks to our laboratorymoderator, Prof. Gerold Pedemonte, of the National Institute ofPhysics for guiding and giving us the support needed throughout theexperiment and this whole semester

Engineering Library 1 for giving us the charge of our laptop batteries

Our deep sense of gratitude to NIP staff, Mr. Romy Albaniel for theassistance of lending the materials essential for our the experiment

For the additional 2 weeks of editing, thank you.


15/15

References

Convective Current

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatr

Abstract Examples

http://writing.wisc.edu/Handbook/presentations_abstracts_examples.html

Heat Transfer

Physics 73.1 Lab Manual

http://www.simetric.co.uk/si_water.htma.html
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effects of varying points of heat application to ice at confined volume

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