Things that go boom? Need to present to some kids

On 10/26/2019 4:58 AM, Cursitor Doom wrote:
On Fri, 25 Oct 2019 19:27:18 -0400, Joseph Gwinn wrote:

When I was a kid (old enough to play unsupervised), one simple thing I
did was to explode copper bridge wires underwater, in a half-filled fish
tank. The bang could splash a lot of water onto the floor.

I'm surprised no one's mentioned these little gizmos:

https://www.youtube.com/watch?v=r8DF1036zMQ
Click to expand...

Blasting cap?
 
On 10/24/2019 4:02 PM, John Larkin wrote:
On Thu, 24 Oct 2019 12:28:17 -0700 (PDT), klaus.kragelund@gmail.com
wrote:

Hi

Every year I teach a class in 7th grade about electronics and space stuff

I normally end the presentation with a reverse power capacitor that goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?

Other?


Thanks

Klaus

Dump a big cap or a biggish battery into a resistor?

https://www.dropbox.com/s/gpc169hj1ilp6xa/photo01x_exploded_resistors.jpg?raw=1

Or just AC line voltage.

Makes a controllable bang and smoke.
Click to expand...

A line powered flash bang would be too much? Bet it get their attention. ;-)
 
On 2019/10/24 8:39 p.m., gray_wolf wrote:
On 10/24/2019 4:02 PM, John Larkin wrote:
On Thu, 24 Oct 2019 12:28:17 -0700 (PDT), klaus.kragelund@gmail.com
wrote:

Hi

Every year I teach a class in 7th grade about electronics and space
stuff

I normally end the presentation with a reverse power capacitor that
goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to
avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?

Other?


Thanks

Klaus

Dump a big cap or a biggish battery into a resistor?

https://www.dropbox.com/s/gpc169hj1ilp6xa/photo01x_exploded_resistors.jpg?raw=1


Or just AC line voltage.

Makes a controllable bang and smoke.


Resistors across the power line is a good trick. An Instructor in AF
electronics school liked to
connect one across the line in an AC power plug and tell the student to
plug it in. Woke everybody up.
Click to expand...

Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.

John :-#)#

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(Please post followups or tech inquiries to the USENET newsgroup)
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mandag den 28. oktober 2019 kl. 21.09.31 UTC+1 skrev John Robertson:
On 2019/10/24 8:39 p.m., gray_wolf wrote:
On 10/24/2019 4:02 PM, John Larkin wrote:
On Thu, 24 Oct 2019 12:28:17 -0700 (PDT), klaus.kragelund@gmail.com
wrote:

Hi

Every year I teach a class in 7th grade about electronics and space
stuff

I normally end the presentation with a reverse power capacitor that
goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to
avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?

Other?


Thanks

Klaus

Dump a big cap or a biggish battery into a resistor?

https://www.dropbox.com/s/gpc169hj1ilp6xa/photo01x_exploded_resistors.jpg?raw=1


Or just AC line voltage.

Makes a controllable bang and smoke.


Resistors across the power line is a good trick. An Instructor in AF
electronics school liked to
connect one across the line in an AC power plug and tell the student to
plug it in. Woke everybody up.


Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.
Click to expand...

https://youtu.be/bnFkCZCsikU
 
On 2019/10/28 1:29 p.m., Lasse Langwadt Christensen wrote:
mandag den 28. oktober 2019 kl. 21.09.31 UTC+1 skrev John Robertson:
On 2019/10/24 8:39 p.m., gray_wolf wrote:
On 10/24/2019 4:02 PM, John Larkin wrote:
On Thu, 24 Oct 2019 12:28:17 -0700 (PDT), klaus.kragelund@gmail.com
wrote:

Hi

Every year I teach a class in 7th grade about electronics and space
stuff

I normally end the presentation with a reverse power capacitor that
goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to
avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?

Other?


Thanks

Klaus

Dump a big cap or a biggish battery into a resistor?

https://www.dropbox.com/s/gpc169hj1ilp6xa/photo01x_exploded_resistors.jpg?raw=1


Or just AC line voltage.

Makes a controllable bang and smoke.


Resistors across the power line is a good trick. An Instructor in AF
electronics school liked to
connect one across the line in an AC power plug and tell the student to
plug it in. Woke everybody up.


Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.



https://youtu.be/bnFkCZCsikU
Click to expand...

I didn't realize that electric hot dog cookers (direct connection to
power line) were made in the USA! Unlike the youtube example I did my
electrocution a 115VAC not 220/240VAC...

John :-#)#
 
mandag den 28. oktober 2019 kl. 21.57.06 UTC+1 skrev John Robertson:
On 2019/10/28 1:29 p.m., Lasse Langwadt Christensen wrote:
mandag den 28. oktober 2019 kl. 21.09.31 UTC+1 skrev John Robertson:
On 2019/10/24 8:39 p.m., gray_wolf wrote:
On 10/24/2019 4:02 PM, John Larkin wrote:
On Thu, 24 Oct 2019 12:28:17 -0700 (PDT), klaus.kragelund@gmail.com
wrote:

Hi

Every year I teach a class in 7th grade about electronics and space
stuff

I normally end the presentation with a reverse power capacitor that
goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to
avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?

Other?


Thanks

Klaus

Dump a big cap or a biggish battery into a resistor?

https://www.dropbox.com/s/gpc169hj1ilp6xa/photo01x_exploded_resistors.jpg?raw=1


Or just AC line voltage.

Makes a controllable bang and smoke.


Resistors across the power line is a good trick. An Instructor in AF
electronics school liked to
connect one across the line in an AC power plug and tell the student to
plug it in. Woke everybody up.


Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.



https://youtu.be/bnFkCZCsikU


I didn't realize that electric hot dog cookers (direct connection to
power line) were made in the USA! Unlike the youtube example I did my
electrocution a 115VAC not 220/240VAC...
Click to expand...

it was meant for 110-120, but BigClive is in the UK

https://youtu.be/n2ZZbuOeNmw
 
<klaus.kragelund@gmail.com> wrote:

Hi

Every year I teach a class in 7th grade about electronics and space stuff

I normally end the presentation with a reverse power capacitor that goes
boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to avoid
the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated? Tantalum reverse biased?

Other?
Click to expand...

Beware of making small hard things go bang, the bits can travel at
extremely high speed and penerate people.

The metal venetian blind in my workshop had one dent from a glass fuse +
holder that couldn't withstand the short-curcuit current and another
from a transistor in a totem-pole power outout stage that turned on at
the same time as its mate during a faulty start-up sequence. By
comparison, the fallout from an overloaded electrolytic capacitor is
relatively predictable and benign.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
On Mon, 28 Oct 2019 14:03:33 -0500, gray_wolf wrote:

> Blasting cap?

Nope. Just airbag detonators. No legal restrictions.




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This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.
 
On a sunny day (Mon, 28 Oct 2019 13:09:19 -0700) it happened John Robertson
<spam@flippers.com> wrote in <yLKdnVHCDbFy1yrAnZ2dnUU7-IHNnZ2d@giganews.com>:

Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.
Click to expand...

I did the same at 220V 50 Hz :)
I did eat several :)
 
On Tue, 29 Oct 2019 09:04:41 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 28 Oct 2019 13:09:19 -0700) it happened John Robertson
spam@flippers.com> wrote in <yLKdnVHCDbFy1yrAnZ2dnUU7-IHNnZ2d@giganews.com>:


Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.

I did the same at 220V 50 Hz :)
I did eat several :)
Click to expand...

Also known as electrician's source.

One problem at least on 220 V is that if the electrode surface might
be too small, it might carbonize the sausage around the electrode.
Using two metallic forks at the ends help spreading the current more
evenly..
 
On 2019-10-24 15:28, klaus.kragelund@gmail.com wrote:
Hi

Every year I teach a class in 7th grade about electronics and space stuff

I normally end the presentation with a reverse power capacitor that goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?
Click to expand...

33-ohm carbon comp resistor across the mains.

Cheers

Phil Hobbs



--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Mon, 28 Oct 2019 13:09:19 -0700, John Robertson <spam@flippers.com>
wrote:

Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.
Click to expand...

Likewise. With the help of my father, when I was in my single digits,
we took a cigar box, lined it with aluminum foil to catch the grease
and set it up for 4 dogs at a time. We used stainless steel wire,
though, to penetrate the hotdogs. Copper doesn't taste very good.

I took it to school as my science project. Comparison between then
and now, instead of running and shouting and panicky and calling the
police and having me expelled for a year, the teacher was fascinated.

.. She got enough hot dogs from the cafeteria for the whole class and
I cooked them up :)

John

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.

John :-#)#
Click to expand...
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address
 
On Thursday, October 31, 2019 at 7:34:10 AM UTC-4, Phil Hobbs wrote:
On 2019-10-24 15:28, klaus.kragelund wrote:
Hi

Every year I teach a class in 7th grade about electronics and space stuff

I normally end the presentation with a reverse power capacitor that goes boom, just so they at least get excited about that.

But, any other component that makes a large boom? (I would like to avoid the cap, since it spills electrolytics and smells bad

DPAK2 FET, with 30W disipated?
Tantalum reverse biased?

33-ohm carbon comp resistor across the mains.
Click to expand...

Turn off the power. Put one or more 1N4148 or other small signal diode across the wall switch for the lights. Make sure that the switch is on and restore power. Wait for the victim to turn the lights off. Laugh!
 
Blowing soap bubbles with Oxyhydrogen and ignite them.

Wim
 
On 28/10/2019 20:09, John Robertson wrote:

<snip>

Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference in
a book/magazine (1960s). As I recall the hot dog cooks until it is done
and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.

John :-#)#
Click to expand...

I did this as part of an electrical safety demo. I used a 500W lamp in
series with a frankfurter using copper plumbing fittings (15mm end
stops) to connect. This was on 240V AC.

Switch on and nothing much happens for a few seconds, then the lamp
starts to glow presumably as the frankfurter skin insulation breaks
down, then the lamp gets brighter and the frankfurter starts to sizzle
and cook.

Then you turn it off because no-one wants a conference room smelling
like that. Too late, it does. The frankfurter ends are green looking,
but it otherwise appears cooked.

Cheers
--
Clive
 
On 07/11/2019 10:56, Clive Arthur wrote:
On 28/10/2019 20:09, John Robertson wrote:

snip

Or...cook a hot dog by plugging each end across the power line - bare
copper wire jammed in each end.

It works...I did that when I was in my teens 'cause I saw a reference
in a book/magazine (1960s). As I recall the hot dog cooks until it is
done and the resistance subsequently went too high to continue. Didn't
carbonize...perhaps hotdogs were a different composition then if your
results are different.

Not sure if I would eat the hotdog now, but copper isn't too much of a
contamination.

John :-#)#

I did this as part of an electrical safety demo.  I used a 500W lamp in
series with a frankfurter using copper plumbing fittings (15mm end
stops) to connect.  This was on 240V AC.

Switch on and nothing much happens for a few seconds, then the lamp
starts to glow presumably as the frankfurter skin insulation breaks
down, then the lamp gets brighter and the frankfurter starts to sizzle
and cook.

Then you turn it off because no-one wants a conference room smelling
like that.  Too late, it does. The frankfurter ends are green looking,
but it otherwise appears cooked.
Click to expand...

I have seen it done with gerkins as a chemistry demo (they don't smell
quite so bad). The trick being that by doping them first in strontium
nitrate, sodium nitrate or barium nitrate they burn with traffic light
colours. It isn't especially safe as live mains experiments go.

--
Regards,
Martin Brown
 
On Thu, 07 Nov 2019 10:56:54 +0000, Clive Arthur wrote:

Then you turn it off because no-one wants a conference room smelling
like that. Too late, it does. The frankfurter ends are green looking,
but it otherwise appears cooked.
Click to expand...

Hmmm. Not only cooked, but ionised as well. Nice!




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