Wow, one watt is really very little energy
 

Every time I come back from riding my bike, the bike computer tells me,
among other useful information like my pulse rate, how high the hills
were, how fast I pedalled, what my road speed was, the temperature,
rates of descent, etc, etc, etc, much more stuff which I have my
computer print out in neat graphs. Among all this the bike computer
tells me how many watts I expended. The thing cheats of course, as it
takes a downhill or level-road ride as zero watts (you're still
expending energy). It gives peak output and an average for the ride. So
the energy expended is the length of the ride (it only ticks the clock
when the wheels are moving) multiplied by the average output. But get
this, one kilowatt-hour is 860kJ. So, if you've gone for a ride that
will burst your average audiophile (middle-aged, overweight, fatarsed,
except for Patrick and me, who are ex-athletes and cyclists still) out
into heavy perspiration, say 100W average for an hour, which allows for
some extended peaks at 250W which will drive his heartbeat up to the
maximum, which does no one any good, is 0.1kW or 86kJ. In other words,
an hour's hard ride burns only 86 nutritional calories. You see, those
calories on food packets are really kiloJoules aka "nutritional
calories". You guys better stop eating altogether or you'll have to be
on your bikes eight hours a day.

Obligatory on-topic comment: That's a worse scam than rating audio gear
in "RMS watts" or "music watts".

Andre Jute
The trouble with most people is not what they don't know, but what they
know for certain that isn't true. ---Mark Twain

Wow, one watt is really very little energy
 

In article . com, Andre
Jute writes
Every time I come back from riding my bike, the bike computer tells me,
among other useful information like my pulse rate, how high the hills
were, how fast I pedalled, what my road speed was, the temperature,
rates of descent, etc, etc, etc, much more stuff which I have my
computer print out in neat graphs. Among all this the bike computer
tells me how many watts I expended. The thing cheats of course, as it
takes a downhill or level-road ride as zero watts (you're still
expending energy). It gives peak output and an average for the ride. So
the energy expended is the length of the ride (it only ticks the clock
when the wheels are moving) multiplied by the average output. But get
this, one kilowatt-hour is 860kJ. So, if you've gone for a ride that
will burst your average audiophile (middle-aged, overweight, fatarsed,
except for Patrick and me, who are ex-athletes and cyclists still) out
into heavy perspiration, say 100W average for an hour, which allows for
some extended peaks at 250W which will drive his heartbeat up to the
maximum, which does no one any good, is 0.1kW or 86kJ. In other words,
an hour's hard ride burns only 86 nutritional calories. You see, those
calories on food packets are really kiloJoules aka "nutritional
calories". You guys better stop eating altogether or you'll have to be
on your bikes eight hours a day.

Obligatory on-topic comment: That's a worse scam than rating audio gear
in "RMS watts" or "music watts".


Interesting to note on a visit to the science museum with the nippers
last year, they have a generator coupled up to a domestic 30 watt light
bulb.

Just quite surprising how much effort is needed to keep that lit for
more than a very short space of time!.....


--
Tony Sayer

Wow, one watt is really very little energy
 

Andre Jute wrote:

You see, those calories on food packets are really kiloJoules aka "nutritional

calories".

No.

As ever you can't get even the tiniest thing right.

1 kilocalorie ( the 'calorie on the packet' ) = ~ 4.2 kiloJoules
http://en.wikipedia.org/wiki/Calorie

Graham

Wow, one watt is really very little energy
 

Andre Jute wrote:

Every time I come back from riding my bike, the bike computer tells me,
among other useful information like my pulse rate, how high the hills
were, how fast I pedalled, what my road speed was, the temperature,
rates of descent, etc, etc, etc, much more stuff which I have my
computer print out in neat graphs. Among all this the bike computer
tells me how many watts I expended. The thing cheats of course, as it
takes a downhill or level-road ride as zero watts (you're still
expending energy). It gives peak output and an average for the ride. So
the energy expended is the length of the ride (it only ticks the clock
when the wheels are moving) multiplied by the average output. But get
this, one kilowatt-hour is 860kJ.

Think your maths is a bit faulty. One watt second is one joule so one watt
hour is 60 x 60 = 3600 joules so one kWHr is 3600kJ which is 860kCalories.

So, if you've gone for a ride that
will burst your average audiophile (middle-aged, overweight, fatarsed,
except for Patrick and me, who are ex-athletes and cyclists still) out
into heavy perspiration, say 100W average for an hour, which allows for
some extended peaks at 250W which will drive his heartbeat up to the
maximum, which does no one any good, is 0.1kW or 86kJ. In other words,
an hour's hard ride burns only 86 nutritional calories.

I think these may be wrong too. it is generally accepted that a human at
rest generates about 100W.

Ian

Wow, one watt is really very little energy
 

Andrew Jute McCoy, while fantasizing its usual tripe babbled:

It gives peak output and an average for the ride. So
the energy expended is the length of the ride (it only ticks the clock
when the wheels are moving) multiplied by the average output. But get
this, one kilowatt-hour is 860kJ. So, if you've gone for a ride that
will burst your average audiophile (middle-aged, overweight, fatarsed,
except for Patrick and me, who are ex-athletes and cyclists still) out
into heavy perspiration, say 100W average for an hour, which allows for
some extended peaks at 250W which will drive his heartbeat up to the
maximum, which does no one any good, is 0.1kW or 86kJ. In other words,
an hour's hard ride burns only 86 nutritional calories. You see, those
calories on food packets are really kiloJoules aka "nutritional
calories". You guys better stop eating altogether or you'll have to be
on your bikes eight hours a day.

So, let's look at the actual facts:

1 joule (J) is the amount of mechanical energy required to displace a
mass of 1 kg through a distance of 1 m with an acceleration of 1 m per
second (1 J = 1 kg × 1 m2 × 1 sec-2). Multiples of 1 000 (kilojoules,
kJ) or 1 million (megajoules, MJ) are used in human nutrition. The
conversion factors between joules and calories a 1 kcal = 4.184 kJ,
or conversely, 1 kJ = 0.239 kcal.

1 watthour = 0.859 845 228 Calorie [nutritional]
1 kilojoule = 0.238 845 897 Calorie [nutritional]
700 watthour = 0.938 715 476 horsepower hour
The power output of the human body is about 80 watts at rest, equal to
a bright light bulb.
The brain operates at about 10 watts- equivalent to a dim bulb (some
say ~20% of overall energy use).
Running at 6 mph brings power output up to about 700 watts (close to 1
horsepower)

So, just sitting still burns ~68.8 calories/hour. This suggests a diet
of ~1600 calories/day will meet absolute minimal *energy* needs for the
typical human. To be clearly distinguished from nutritional needs.

Assume a brisk bicycle ride is the equivalent of running at 6mph. Do
this for one hour. This will burn something just over 600 nutritional
calories.

Lastly, walking one mile and running one mile uses _exactly_ the same
amount of energy, as this is a function of mass x distance. Running
provides additional benefits for those who can tolerate it, but the
simple act of walking also provides very real benefits.

Mr. McCoy's math is as accurate as its circuit designs.

Peter Wieck
Wyncote, PA

Wow, one watt is really very little energy
 

Ian Bell wrote:

I think these may be wrong too. it is generally accepted that a human at
rest generates about 100W.


That's about 2000 Calories per day so about right but people generally
talk about the extra energy used during exercise compared to resting.

A good measure is that a fat bloke climbing a flight of stairs uses a
Calorie.
Of course it depends on how fat you are and the dimensions of your office
but it's good enough for your lunchtime exercise calculations.

--
Eiron.

Wow, one watt is really very little energy
 

Soundhaspriority wrote:

Quite true. My understanding is that exercise works because the muscle
metabolism remains elevated long after the activity has ceased.

Muscle metabolism remains "elevated" after exercise stops exactly as
long as it takes to remove the lactic acid and other toxic byproducts,
and perhaps to heal any damage caused by the exercise (such as pulls
and strains). This in part explains why one may maintain a lower level
of activity much longer than one may maintain the functional equivalent
of a sprint. If the products of exercise may be removed as they are
being generated the toxins do not build up (as much) and exercise may
be continued much longer for a potentially greater benefit. The point
is that one _does not_ wish to build up lactic acid during normal
exercise. Those sorts of muscular and systemic insults are usually
reserved for performance occasions.

Excercise "works" because muscle mass is maintained and/or gained due
to use. Such gains may be targeted by special exercises and special
work-outs that concentrate on specific muscle groups, but the point of
all of them is to enhance muscle performance through their use. What
lasts are those gains... but only as long as the exercise that
produced them in the first place continues.

There is a LOT of bad information flying about. It is a damned good
thing this is a Tube-related NG, so few here will be affected by it.

Peter Wieck
Wyncote, PA

Wow, one watt is really very little energy
 

I imagine the guys who turned a slip of the typing finger into a major
flamewar are all fat and diseased from sitting at their keyboards all
day long waiting to catch someone's fart so they can light it to start
a flamewar. Here, with thanks to those who offered amendation, is the
corrected version in which, as Ian Bell has pointed out, 1kW is still
860kcal, so that the conclusion I intended is changed not one jot or
tittle:

Every time I come back from riding my bike, the bike computer tells me,
among other useful information like my pulse rate, how high the hills
were, how fast I pedalled, what my road speed was, the temperature,
rates of descent, etc, etc, etc, much more stuff which I have my
computer print out in neat graphs. Among all this the bike computer
tells me how many watts I expended. The thing cheats of course, as it
takes a downhill or level-road ride as zero watts (you're still
expending energy). It gives peak output and an average for the ride. So
the energy expended is the length of the ride (it only ticks the clock
when the wheels are moving) multiplied by the average output. But get
this, one kilowatt-hour is 860kcal. So, if you've gone for a ride that
will burst your average audiophile (middle-aged, overweight, fatarsed,
except for Patrick and me, who are ex-athletes and cyclists still) out
into heavy perspiration, say 100W average for an hour, which allows for
some extended peaks at 250W which will drive your heartbeat up to the
maximum, which does no one any good, the energy expended is 0.1kW or
86kcal. In other words, an hour's hard ride burns only 86 nutritional
calories. You see, those calories on food packets are really
kilocalories aka "nutritional calories". You guys better stop eating
altogether or you'll have to be on your bikes eight hours a day.

Obligatory on-topic comment: Turning every thousand calories into a
"calory" without warning is a worse scam than rating audio gear in "RMS
watts" or "music watts".

ADDENDUM: Exercise energy expenditure is measured as the additional
energy burned over the maintenance energy at rest of about 100W per
hour.

Andre Jute
The trouble with most people is not what they don't know, but what they
know for certain that isn't true. ---Mark Twain

Wow, one watt is really very little energy
 

Andrew Jute McCoy behaved as predicted with:

I imagine the guys who turned a slip of the typing finger into a major
flamewar are all fat and diseased from sitting at their keyboards all
day long waiting to catch someone's fart so they can light it to start
a flamewar. Here, with thanks to those who offered amendation, is the
corrected version in which, as Ian Bell has pointed out, 1kW is still
860kcal, so that the conclusion I intended is changed not one jot or
tittle:


When one makes a "slip" as if one were speaking revealed religion, the
consequences are hardly flames and the single appropriate response is
"whoops, I erred".

Now, that would be the response of a reasonable human being, not a
latter-day Moses such as yourself so you may be forgiven under those
conditions. But just keep in mind that Moses never reached the Holy
Land... and as it happens that description is quite appropriate in your
case as well.

Peter Wieck
Wyncote, PA

Wow, one watt is really very little energy
 

Andre Jute wrote:

Here, with thanks to those who offered amendation, is the
corrected version in which, as Ian Bell has pointed out, 1kW is still
860kcal

No it sodding well isn't !

*1kWh* is 860kcal.

You simply can't get anything right can you, even on your so-called 'correction'
post.

Graham