Things that go boom? Need to present to some kids

Guest
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
 
Rheilly Phoull wrote:

----------------------

Burn up a speaker ?
Click to expand...

** Been there, done that.

Even using DC, its slow, boring and smelly.



...... Phil
 
On 25/10/2019 3:28 am, 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
Click to expand...

Burn up a speaker ?
 
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
Click to expand...

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.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
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
Click to expand...
What about the flour, candle, paint can, grain dust explosion example?
I'd think its safer than tiny parts flying around. Just the lid will
fly up and hit the ceiling.

Cheers
 
On 24/10/2019 20:28, 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?

Other?


Thanks

Klaus
Click to expand...

Iron wire. Sparks!

Cheers
--
Clive
 
On Thu, 24 Oct 2019 23:49:14 +0100, Clive Arthur
<cliveta@nowaytoday.co.uk> wrote:

On 24/10/2019 20:28, 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?

Other?


Thanks

Klaus

Iron wire. Sparks!

Cheers
Click to expand...

I have always had great luck using a 1/4 watt carbon film 1K Ohm
resistor on 120 VAC.

Back in my my audio days, we would connect up the 1K resistor to the
amplifier load bank and so when the tech would fire up his bench for
the day and the first amplifier, he would get a swell surprise. Adding
a firecracker to that would REALLY get a response !

Kids also love Jacob's Ladders.
 
On 10/24/2019 6:53 PM, boB wrote:
On Thu, 24 Oct 2019 23:49:14 +0100, Clive Arthur
cliveta@nowaytoday.co.uk> wrote:

On 24/10/2019 20:28, 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?

Other?


Thanks

Klaus

Iron wire. Sparks!

Cheers


I have always had great luck using a 1/4 watt carbon film 1K Ohm
resistor on 120 VAC.

Back in my my audio days, we would connect up the 1K resistor to the
amplifier load bank and so when the tech would fire up his bench for
the day and the first amplifier, he would get a swell surprise. Adding
a firecracker to that would REALLY get a response !

Kids also love Jacob's Ladders.
Click to expand...
I thought it was a 1/2 watt, but anyway, it was wired in the big
Weller soldering iron, when it smoked, what smoked and what was it's job?

Mikek :)
 
On 10/24/2019 5:49 PM, Clive Arthur wrote:
On 24/10/2019 20:28, 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?

Other?


Thanks

Klaus

Iron wire.  Sparks!

Cheers
Click to expand...

Steel wool and a small firecracker?
 
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...

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.
 
Maybe launch a rocket? You could give specs on the electronic igniter circuit and ask how many AA batteries in series and/or parallel.?

George H.
 
klaus.kragelund@gmail.com writes:

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
Click to expand...

As a I kid I enjoyed 'welding' with some 30-50mF cap, power supply and
aluminum wires or steel wool. Not a big boom, but a lot of nice sparks.


--
mikko
 
On a sunny day (Thu, 24 Oct 2019 12:28:17 -0700 (PDT)) it happened
klaus.kragelund@gmail.com wrote in
<8bb8c7a0-4d1e-452c-8afa-777cb316c003@googlegroups.com>:

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
Click to expand...

300 W amp and big woofer, some sound track.
Other noises possible too.
Kids will find a use for that, not very dangerous.

In my school days I scored a big 220 V flash bulb, edison base,
screwed it in in pace of house normal light bulb.
Just wait until somebody switched on the light,,,
 
On 10/25/2019 1:34 AM, Jan Panteltje wrote:
On a sunny day (Thu, 24 Oct 2019 12:28:17 -0700 (PDT)) it happened
klaus.kragelund@gmail.com wrote in
8bb8c7a0-4d1e-452c-8afa-777cb316c003@googlegroups.com>:
Click to expand...

[snip]

300 W amp and big woofer, some sound track.
Other noises possible too.
Kids will find a use for that, not very dangerous.

In my school days I scored a big 220 V flash bulb, edison base,
screwed it in in pace of house normal light bulb.
Just wait until somebody switched on the light,,,
Click to expand...

If this works check the tail end with volume turned on good speakers
 
On Thursday, October 24, 2019 at 1:28:24 PM UTC-6, klaus.k...@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
Click to expand...

My kids always enjoyed the steel wool and 9V battery demonstration.

https://www.youtube.com/watch?v=KmZeGix8gvg
 
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
Click to expand...
Typical trick is pass an inductor around room one way, and a battery
around the other way.
 
On Oct 24, 2019, klaus.kragelund@gmail.com wrote
(in article<8bb8c7a0-4d1e-452c-8afa-777cb316c003@googlegroups.com>):

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.
Click to expand...
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.

The equipment consisted of two insulated solid #14 (1.8 mm) copper wire
pieces about a foot long clamped in parallel using some wood and screws. The
far ends were stripped bare, and had a bit of #36 (0.127 mm) wire bridging
the two #14 wires, which were connected to 115 Vac power via a large knife
switch.

No, the 15-amp circuit breakers never popped - the bridgewire blew too fast.

Joe Gwinn
 
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.
Click to expand...

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

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



--
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.
 
Thank you all for the comments

I used the shorted cap for welding/sparks, a small speaker at DC to show how sound sort of works and especially the 1k resistor at mains, which gave a good loud effect

I normally reverse bias a cap, but we were inside, so too much mess doing that

Cheers

Klaus
 
On Thu, 24 Oct 2019 12:28:17 -0700 (PDT), klaus.kragelund@gmail.com
wrote:


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...

Nah. Piker stuff.

I have a friend who has a garage full of 75uF, 25kV pulse capacitors.
I'm badly wanting about 4 of 'em but he's in NY and I'm in TN and I
don't go anywhere my guns aren't welcome.

One or two of those would make quite a noise-maker when discharged
across a ball gap. Make a good can and quarter shrinker too.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address
 
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