Go Back   Science Forums Biology Forum Molecular Biology Forum Physics Chemistry Forum > General Science Forums > Chemistry Forum
Register Search Today's Posts Mark Forums Read

Chemistry Forum Chemistry Forum. Discuss chemical reactions, chemistry.


heat and temperature

heat and temperature - Chemistry Forum

heat and temperature - Chemistry Forum. Discuss chemical reactions, chemistry.


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-18-2003, 12:59 AM
ruth o'hara
Guest
 
Posts: n/a
Default heat and temperature



I am looking for an effective way to explain a High school student the
difference between heat and temperature. Sometimes kids have these
misconceptions about scientific terms which might hinder their
progress in learning. can you think of a helpful analogy, perhaps?
Reply With Quote
  #2  
Old 08-18-2003, 01:47 AM
Marvin Margoshes
Guest
 
Posts: n/a
Default heat and temperature


"ruth o'hara" <[Only registered users see links. ]> wrote in message
news:f81fdf5e.0308171659.7e6dd9a6@posting.google.c om...

How about explaining that temperature is a numerical measure of the property
called heat? Like weight measures mass.

In common speech, folks get the two wordsconfused. I was visiting a friend
in the hospital today, when the nurse came in and took here temperature. My
friend asked the nurse, "Any temperature?" The nurse answered, "No." In
science, we try to use words more specifically.



Reply With Quote
  #3  
Old 08-18-2003, 03:18 AM
Mark Thorson
Guest
 
Posts: n/a
Default heat and temperature

Marvin Margoshes wrote:


No, it's not. Heat is energy. Temperature is like voltage.
You could have an object with a very high temperature
but very little heat, like a small lightbulb filament.



Reply With Quote
  #4  
Old 08-18-2003, 06:39 AM
Barry Hunt
Guest
 
Posts: n/a
Default heat and temperature


"ruth o'hara" <[Only registered users see links. ]> wrote in message
news:f81fdf5e.0308171659.7e6dd9a6@posting.google.c om...

An analogy I was shown at school to explain voltage and amperage may help.
Imagine a reservoir of water with an outlet at the bottom. The temperature
(voltage) is the height of the water level - giving pressure at the outlet.
The heat is the volume of water stored - giving a usable amount of work.

A tall thin reservoir is high temp/low heat, a wide low reservoir is low
temp/high heat storage.

(In the electricity analogy the length/diameter of the outlet is the
resistance)


HTH

Barry Hunt


Reply With Quote
  #5  
Old 08-18-2003, 07:55 AM
Gene Nygaard
Guest
 
Posts: n/a
Default heat and temperature

"Marvin Margoshes" <[Only registered users see links. ]> wrote in message news:<[Only registered users see links. ]>...

Bullshit.

The simple linguistics fact is that these are two ambiguous words,
each with several different meanings.

We don't normally "confuse" any two meanings. Many like you "are
confused," however. The point I'm trying to make is the difference
between "to confuse" on the one hand and "to be confused" on the
other.

In common speech, we use most often use the word we own--the one we
have a prior claim to--when we talk about "net weight" of something
(always mass, never force) or "troy weight" of a bar of gold or
platinum (always mass, never force--unlike their avoirdupois cousins
and unlike grams and kilograms, troy pounds and ounces have never
spawned a force unit of the same name) or "carat weight" of a diamond
(always mass, never force) or the "weight" of a bullet (whether in
grains or grams, both units of mass). Then in scientific speech, we
also have "dry weight" in various applications, as well as "atomic
weight" and "molecular weight."

This "weight" is being used in its original meaning, the way we have
used it continuously for over a millennium in the English language.
This word was invented more than 1000 years ago to mean the quantity
measured with a balance. That quantity is mass (in its modern physics
jargon meaning; of course mass didn't have that meaning at the time
the word "weight" was invented), not force. What do you see as an
error? That these heathens who invented this word were too stupid to
figure out the God-given word they were supposed to invent for this
purpose? There was no error then, and there is no error today when we
continue to use the same word with the same meaning for the same
purposes.

We have a clear prior claim to this word over those who borrowed the
word "weight" only about 275 years ago and often use it with a
different meaning. We have every right to continue to use it with
this meaning. We are not shopping for a new word, much as you might
like us to give up our prior claim to this word.

Of course, the fact that the only science involved here is linguistics
is well illustrated by the fact that this is a language specific
problem, one shared by English with some other languages (i.e.,
French) but not by others. For example, when physicists using
Norwegian were shopping for a jargon word, they didn't choose "vekt"
(spelled vigt, wgt, etc. in various times and places), the cognate of
the English weight, but rather "tyngde."

In English, of course, it wasn't even the physicists who choose this
word--that choice was made for them by Andrew Motte, an otherwise
unknown translator, when he translated Newton's major work into
English after Newton's death.

Isaac Newton never used weight with the meaning you claim is its
God-given meaning.

Now pay close attention, and see who it is (people like you) who are
suffering the confusion mentioned by the experts in the field, who
know what they are talking about in this regard:

The National Standard of Canada, CAN/CSA-Z234.1-89 Canadian Metric
Practice Guide, January 1989, says something similar:

5.7.3 Considerable confusion exists in the use of the
term "weight." In commercial and everyday use, the
term "weight" nearly always means mass. In science
and technology, "weight" has primarily meant a force
due to gravity. In scientific and technical work, the
term "weight" should be replaced by the term "mass"
or "force," depending on the application.

5.7.4 The use of the verb "to weigh" meaning "to
determine the mass of," e.g., "I weighed this object
and determined its mass to be 5 kg," is correct.

As they say, "confusion exists." That doesn't necessarily mean that
anyone whatsoever "confuses" anything. In this case, you are in the
class for whom this confusion is identified as existing.

Here one important thing to note is the difference in the use of the
noun forms, which are context-specific, and the verb forms, for which
this meaning is unqualifiedly correct with these meanings (and which
is also correct for determining the force due to gravity, of course).

Note also that "nearly always" is much stronger than "primarily"--they
even got that part right.

Here's a FAQ by the NPL, the national standards laboratory of the
U.K.:
[Only registered users see links. ]

Weight
In the trading of goods, weight is taken to mean the
same as mass, and is measured in kilograms. Scientifically
however, it is normal to state that the weight of a
body is the gravitational force acting on it and hence
it should be measured in newtons, and this force
depends on the local acceleration due to gravity.
To add to the confusion, a weight (or weightpiece)
is a calibrated mass normally made from a dense
metal, and weighing is generally defined as a
process for determining the mass of an object.

So, unfortunately, weight has three meanings
and care should always be taken to appreciate
which one is meant in a particular context.


Note--they clearly refer to different *meanings* of this word.


Here's NIST, the U.S. national standards agency, in their Guide for
the Use of the International System of Units, NIST Special Publication
811,
[Only registered users see links. ]

In commercial and everyday use, and especially in common
parlance, weight is usually used as a synonym for mass.
Thus the SI unit of the quantity weight used in this
sense is the kilogram (kg) and the verb "to weigh" means
"to determine the mass of" or "to have a mass of".

Examples: the child's weight is 23 kg
the briefcase weighs 6 kg
Net wt. 227 g

American Society for Testing and Materials, Standard for Metric
Practice, E 380-79, ASTM 1979, sec. 3.4.1.2

3.4.1.2 Considerable confusion exists in the use
of the term weight as a quantity to mean either force
or mass. In commercial and everyday use, the term
weight nearly always means mass; thus, when one
speaks of a person's weight, the quantity referred
to is mass. . . .
Because of the dual use of the term weight as a
quantity, this term should be avoided in technical
practice except under circumstances in which its
meaning is completely clear. When the term is
used, it is important to know whether mass or
force is intended and to use SI units properly as
described in 3.4.1.1, by using kilograms for
mass or newtons for force.


Talking about the sale of cheese in a chemistry or physics class
doesn't change the rules governing such a sale. See "Physicist qua
cheesemonger (U. of Winnipeg)" on alt.usage.english and sci.physics
(most messages in both, some in other groups as well, all in one or
the other of these),
[Only registered users see links. ]

The context determines whether or not a particular definition is
appropriate for use. You can choose not to use the word "weight" with
this meaning, but if you do use the word weight concerning the sale of
cheese or cherries or whatever, please use the very specific meaning
appropriate for that purpose. We like to use our words
specifically--can you get that simple fact through your thick head?

--
Gene Nygaard
[Only registered users see links. ]
"It's not the things you don't know
what gets you into trouble.

"It's the things you do know
that just ain't so."
Will Rogers
Reply With Quote
  #6  
Old 08-18-2003, 09:19 AM
ruth o'hara
Guest
 
Posts: n/a
Default heat and temperature

"Barry Hunt" <[Only registered users see links. ].au> wrote in message news:<bhps9m$13fd$[Only registered users see links. ].au>...

Thanks everybody for your time and input. It is appreciated and it's been helpful.
Reply With Quote
  #7  
Old 08-18-2003, 11:58 AM
Buckleys
Guest
 
Posts: n/a
Default heat and temperature

Richard Schultz wrote:
<snip>

Not low heat capacity, low thermal conductance.

Rob.


Reply With Quote
  #8  
Old 08-18-2003, 12:46 PM
PSmith9626
Guest
 
Posts: n/a
Default heat and temperature

Dear mark,
Flawed. Temperature is NOT like voltage.
Voltage is potential energy.
best
Penny

Heat is defined by statistical mechanics and so is temperature. High School
kids should take physics and should be able to handle a few equations.



Reply With Quote
  #9  
Old 08-18-2003, 05:38 PM
Repeating Decimal
Guest
 
Posts: n/a
Default heat and temperature

in article [Only registered users see links. ], PSmith9626 at
[Only registered users see links. ] wrote on 8/18/03 5:46 AM:

Certain statistical mechanics concepts are not that difficult. There is much
in chemistry and physics, such as vapor pressure and gas laws that can be
explained that way. How much genius is required to understand that bouncing
lots of molecules at high velocity against a piston in an engine will cause
the piston to move. Poorly educated hot-rodders of the past were able to
learn that easily.

Bill

Reply With Quote
  #10  
Old 08-18-2003, 07:22 PM
Fred Kasner
Guest
 
Posts: n/a
Default heat and temperature

ruth o'hara <[Only registered users see links. ]> wrote:

--
I am afraid that what was presented to you by the other responses did
a magnificent job of using an atomic reactor to squash a fly - especially
that incredible tirade of the off topic reference to mass and weight. The
key issue is that both terms are thermal terms and refer to the random
kinetic energy of molecules. We call the extensive term heat. We call the
intensive term temperature. As there is no average kinetic energy per
gram term we must be satisfied with a term proportional to the average
kinetic energy. The key lies in the definition of intensive and extensive.
FK

[Only registered users see links. ]
SDF Public Access UNIX System - [Only registered users see links. ]
Reply With Quote
Reply

Tags
heat , temperature


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can body heat be converted into energy? Sanny Physics Forum 11 08-25-2008 10:48 PM
GNU units and units.dat; Units of Measurement and Unit Conversion James Redford Physics Forum 0 07-31-2005 12:08 PM
Specific Heat Capacity John Eccles Physics Forum 1 03-07-2004 09:35 PM
The Classical Vacuum - by Timothy H. Boyer Laurent Physics Forum 8 01-14-2004 03:49 PM
Simulating a Heatsink Zachary Physics Forum 1 12-25-2003 05:21 AM


All times are GMT. The time now is 03:34 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 - 2012 Molecular Station | All Rights Reserved
Page generated in 0.21425 seconds with 16 queries