Note, do NOT leave bubble wrap on the floor

[jc101]

I let the end of a roll of bubble wrap drape down to floor level.  It happens fairly often, as my office / lab is quite small, especially with a new roll as they are quite large.

What harm can this do?  Well, when testing a power supply, and you then roll your chair over the end of the bubble wrap, the rapid and loud popping noise becomes a problem.  Including thinking the PSU has decided to let go in a big way, rushing to turn it off, causing more popping noises as the chair rolls back along the bench to show the power off.

I'll just say my language was 'fragrant'.

[Fred27]

Next you'll be telling us that we can't burst a crisp packet when someone is powering on a very expensive piece of equipment.

[TimFox]

One of my fellow graduate students had the bad habit of cracking his knuckles when we were taking up high voltage equipment.

[Gyro]

Next you'll be telling us that we can't burst a crisp packet when someone is powering on a very expensive piece of equipment.

In my day, it was a good squirt of freezer spray into a 35mm film can and then rolled under the victim's bench. 

[jc101]

Next you'll be telling us that we can't burst a crisp packet when someone is powering on a very expensive piece of equipment.

In my day, it was a good squirt of freeze spray into a 35mm film can and then rolled under the victim's bench. 

Oh I like that, I even think I could make use of that in the not too distant future 

[VK3DRB]

About 35 years ago, we were installing the first of a particular high end tape drive in Australia. It was a complicated installation and test procedure, taking two engineers about three hours. I got my colleague to power it up for the first time and behind him I clapped one loud clap where the timbre of the sound was as if a capacitor had gone off. He got one heck of a fright. Despite him "deserving it", as he was a self righteous judgemental kind of fellow, in retrospect it was a bloody stupid thing to do. I did apologise to him afterwards (half heartedly).

[Neilm]

Next you'll be telling us that we can't burst a crisp packet when someone is powering on a very expensive piece of equipment.

In my day, it was a good squirt of freezer spray into a 35mm film can and then rolled under the victim's bench. 

What is a 35 mm film can? 

An electrolytic or Tantlum wired backwards is always fun...

[duak]

When I was debugging and limit testing a PWM servo driver I designed, I would get the occasional kapop, and not always when it was expected.  Yeah, bursting bubble wrap would still startle me.

A friend worked at a local telecom assembly and test line.  After the crew came back from lunch he turned on the unit under test and there was a little pop and some smoke came out of it.  He shut it off and looked carefully to see what had blown.  He heard some supressed chuckling from the bench he was backed on, then saw some small diameter heat shrink tubing running through the cables and divider.  The joker had popped some bubble wrap and then blew a bit of cig smoke into the tubing.  It's funny once, no?

[nigelwright7557]

its like the classic mechanics trick of honking horn when someone has their head under the bonnet.

[nali]

Back in my apprentice days it was a piece of rubber cable sleeve over the end of a freezer spray pipe, folded over & cable tied. They used to balloon up then go with one hell of a bang a bit like a starter pistol.

[Gyro]

Next you'll be telling us that we can't burst a crisp packet when someone is powering on a very expensive piece of equipment.

In my day, it was a good squirt of freezer spray into a 35mm film can and then rolled under the victim's bench. 

What is a 35 mm film can? 

An electrolytic or Tantlum wired backwards is always fun...

Ah, the youth of today.    It was a small plastic (or sometimes aluminium) cylindrical container with a sealed tight fitting plastic lid - used for storing and protecting 35mm still photographic film canisters when new, and after exposure. Easy to flip up from the edge but it takes a surprisingly large amount of internal pressure to pop it off.

Equally useful for small parts storage and modification into small enclosures.

[bd139]

“Catch the 200v charged electrolytic” was a good game at university. 25 years later if anyone throws anything at me I still automatically avoid catching it.

[vk6zgo]

The very large bubble wrap which is sometimes used is excellent for startling someone doing something requiring their full concentration.

One job like this is "tweaking" the convergence on a Sony Trinitron, which is usually done using so-called "convergence wands" (plastic strips with a small section of material on one end having a magnetic permeability differing from that of air.).

In use, they are slid under the deflection yoke, &  their position adjusted whilst watching the screen through a mirror.

This entails groping around in close proximity to "hot" terminals on the yoke, so the person doing this is already understandably nervous.
A sudden "bang" behind them has interesting results!

Years before that  I worked at a large radio station which had a cable tunnel underneath the Tx hall.
We used to carry "clipboards" to record meter readings on, & discovered that the sound made by opening the clip & letting it slam shut, after echoing around the tunnel, sounded just like a circuit breaker dropping out.

Great for making the guy in the control room jump!

[temperance]

I worked at a company servicing 2kW to 20kW switching power supplies. One guy always thought it was funny to sneak around my desk and clap his hands next to my ears when he saw me carefully probing live circuits with large capacitors (36000µF) charged to 420V. Very dangerous stuff and it requires full concentration to not end up dead. Long story short: this not so funny guy got electrocuted when he was servicing a three phase powered system when he grabbed the bus bars while the equipment was plugged in. His magic smoke escaped. Karma koma

If you really like doing this kind of things to your colleagues, do not wait till the end of the day is near. It will take a while for the legal instances to investigate the scene and you might not be home in time for dinner.

[themadhippy]

A bit of solder across the terminals of a lamp holder was an old  favorite .Also leaving open ends on micc  cables after doing a 1000v insulation test was  fun

[Cyberdragon]

its like the classic mechanics trick of honking horn when someone has their head under the bonnet.

Shove a shaken can of soda into some hydraulics under test.

[nali]

Ah, the youth of today.    It was a small plastic (or sometimes aluminium) cylindrical container with a sealed tight fitting plastic lid - used for storing and protecting 35mm still photographic film canisters when new, and after exposure. Easy to flip up from the edge but it takes a surprisingly large amount of internal pressure to pop it off.

Heh. If you want a bit more old skool - a magnesium flash bulb across the power rails  Admittedly that's a bit before my time though so no idea if anyone really used to try that, it was "what we used to do" conversations from the older guys.

[Berni]

Yep did the roll a chair over bubble wrap before, but luckily during just working at a PC. The sound it makes is spot on to the horrible noise of catastrophically failing power electronics, the only thing missing are the flying sparks and bunt smell.

But in terms of pranks we used power resistors instead. Put one of those across a lab supply to get it nice and toasty and then just hand it to someone while you hold it by one of the pins (Just don't make it hot enough to actually cause a serious burn).

[vk6zgo]

Another old trick is to roll a turn or so of solder off the reel, cut the length in half & insert a piece of tinned copper wire (TCW), soldering it to the solder (it sounds a bit difficult, but it really isn't.)

Roll the "doctored" length back on, & leave the roll where someone is likely to be doing a lot of solder joints.
They won't notice the TCW until they try to heat the end & the heat runs straight up the copper to their fingers!

[TimFox]

I used to tell the junior engineers who enjoyed popping bubble wrap between their fingers that mental institutions used this exercise as therapy for their patients.

[aargee]

A plastic ruler flexed and snapped back down on the workbench has a similar effect.

[larrybl]

“Catch the 200v charged electrolytic” was a good game at university. 25 years later if anyone throws anything at me I still automatically avoid catching it.

We did this too in Vo-Tech, but mixed it up with vacuum tubes so you had to decide in a split weather to catch or pass.

[ConKbot]

Another old trick is to roll a turn or so of solder off the reel, cut the length in half & insert a piece of tinned copper wire (TCW), soldering it to the solder (it sounds a bit difficult, but it really isn't.)

Roll the "doctored" length back on, & leave the roll where someone is likely to be doing a lot of solder joints.
They won't notice the TCW until they try to heat the end & the heat runs straight up the copper to their fingers!

I've grabbed a roll of solid, tinned, uninsulated wire instead of solder before, it was thin enough I didn't notice it wasn't as soft as it should be. Spent 5 minutes mucking with the soldering station,as the new JBCs were way more flaky than the old ones, and would burn up tips when they failed to recognize the iron was back in the holder.