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Killa-X

Mon Dec 06 2010, 11:09PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Well..I did a 300 / 450V shot to a penny today. 500J out of 980J. I always wonder exactly how much power that is, besides "Oh it can fire a ring XXX feet" I was surprised to be honest. Seeing I don't play with bombs or anything. I had 30db reducing earmuffs, and it still seemed like a loud thud. The explosion was strong enough that i felt a thud in my chest. My mom, who was in the house, near other side, even said it sounded loud. This made me a bit afraid to be playing with 500J...And im a bit afraid of 1KJ. I'm not going to discharge 1KJ now to a solid short. After hearing how loud half power was, im not going to risk complaints. This makes me a tad nervous for my 1KJ bank, 4KJ, and 12KJ banks. I'm going to have to test these in a field...

But wow..Such a bang of energy =D Loved it!

The black crap on my driveway was from that single 300V 500J shot. Messy.

Adam Munich

Tue Dec 07 2010, 02:06AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Killa-X wrote ...

I always wonder exactly how much power that is, besides "Oh it can fire a ring XXX feet"

Killa-X

Tue Dec 07 2010, 03:42AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Grenadier wrote ...

Killa-X wrote ...

I always wonder exactly how much power that is, besides "Oh it can fire a ring XXX feet"

Nice site full of false information.

First. 1 Calorie, is 4.184 Joules.

"Since your body requires 2500 Calories, you burn 10,460,000 Joules of energy every day"

2500 * 4.184 = 10,460J not 10,460,000 Joules.

"energy is in one can of coke. 585,760 Joules to be exact"

One can of coke is 115 Calories. 115 * 4.184 = 481.16J, not 585,760J.......

Or to Google, "155 calories = 648.52 joules"

Adam Munich

Tue Dec 07 2010, 03:58AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

1 calorie = 4.184 J
1 Calorie = 4184 J

Digestible calories in a can of coke = 140C or 140,000c

klugesmith

Tue Dec 07 2010, 07:45AM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Grenadier is right about the numbers -- food nutrition data is given in kilocalories which are called "calories" on American standard labels, for some reason.
(I disagree that the capital C is a standard way to distinguish the units).

Sanity check: an active man burns about 2500 "calories" per day,
which is 10,460,000 joules or around 20 cans of sugary soda.
That's about 121 watts, which is consistent with the average heat dissipation of a live person. 10460 joules per day might sustain a mouse.

Adam Munich

Tue Dec 07 2010, 11:19AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Klugesmith wrote ...
(I disagree that the capital C is a standard way to distinguish the units).

It is actually, at least in the US.

Steve Conner

Tue Dec 07 2010, 11:46AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

On this side of the pond, your diet soda might say "Only 40 calories!" on the label, but on the fine print it's "kcal".

The c/C thing seems wrong. The big ones are kilocalories, or some people call them kilogram-calories and the little ones gram calories, referring to the mass of water that it would heat by one degree centigrade.

We also have SI units, so nobody uses calories for anything other than food, hence you can assume that they're kilocalories by default. Engineering calculations are done in joules. (But bizarrely, boilers and radiators are still sized in BTUs.)

The Australians actually rate their food in kilojoules and their cars in kilowatts, which is a step too far IMO.

Adam Munich

Tue Dec 07 2010, 11:56AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

That's because 99% of people have no clue hat a Calorie is, other than it being a "fat unit".

Fom Wikipedia.

The small calorie or gram calorie (symbol: cal)[2] approximates the energy needed to increase the temperature of 1 gram of water by 1 Â°C. This is about 4.2 joules.
The large calorie, kilogram calorie or food calorie (symbol: Cal)[2] approximates the energy needed to increase the temperature of 1 kilogram of water by 1 Â°C. This is exactly 1000 small calories or about 4.2 kilojoules.

Steve Conner

Tue Dec 07 2010, 12:50PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

OK, it's in Wikipedia. I'd edit it, but it references the Webster Online Dictionary, so it must be technically correct.

That doesn't make it any less dumb, though. Using kcal for the kilogram calorie or kilocalorie avoids a little confusion.

I noticed that one food calorie is 2.6 x 10^22 electronvolts, which would be a fun unit. If an electron ate my dinner, it would probably create a mini black hole or something.

Killa-X

Tue Dec 07 2010, 03:45PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Ah I see now. Didn't know there was a c C making the difference of a thousand. So this means my small 8FL oz of mountain dew, 110 Calories, is 460,240 Joules. Fun. Now if only you could harvest that all into a capacitor right? >_>

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