Ideas for an Exciting Demo

Thread Starter

TechWise

Joined Aug 24, 2018
56
I work in a Power Electronics research group at a university. We do power electronic converters from low power right up to HVDC as well as machine drives and machine design. We are often asked to provide lab tours to anyone from school children applying to university, right through to R & D directors from industry.

We would like to have some sort of exciting demonstration that we can do in the lab as looking at solid state circuits is rather boring for the younger visitors. Ideas have included a linear motor/very low power rail gun of sorts, high voltages that produce arcs or sparks, class D amplifiers that make noise or suchlike, stepper motors that you can see moving and working etc. etc.

Just looking for ideas really. Has anyone seen any cool demos over the years? At the moment the high voltage team is rather stealing our thunder with a tesla coil that plays music!
 

Uilnaydar

Joined Jan 30, 2008
118
If this is the University of Wisconsin - Madison.... ask Professor Ludois. He will point you in the right direction. If not, some of the evil projects he did as a grad student were: Can crusher, tesla coil, skateboard with a GIANT motor drive, a 10' diameter subwoofer with an amp in the kW range....
 

Thread Starter

TechWise

Joined Aug 24, 2018
56
If this is the University of Wisconsin - Madison.... ask Professor Ludois. He will point you in the right direction. If not, some of the evil projects he did as a grad student were: Can crusher, tesla coil, skateboard with a GIANT motor drive, a 10' diameter subwoofer with an amp in the kW range....
I am in the UK. The can crusher sounds like an excellent idea that would impress the kids!
 

Thread Starter

TechWise

Joined Aug 24, 2018
56
You could rig up a piezo crystal so that as the child wiggles a lever, an LED light or spark happens.
We're into magnetic component design as well. This has got me thinking about a demo I've seen before where the children drop magnets down a plastic tube with a coil round it and an LED lights up as the magnet drops through it.

I will have to look into the piezo crystal :)
 

jpanhalt

Joined Jan 18, 2008
8,134
Children's science museums often have some sort of crank generator. The kids invariably compete to see who can make the light brighter.

As for an interesting magnet experiment, just drop a niobium "super" magnet down a narrow, non-magnetic metal tube. Aluminum arrow shafts work well. Let the kids compare how long it takes for the magnet compared to a non-magnet of equal size and weight.
 

Thread Starter

TechWise

Joined Aug 24, 2018
56
Children's science museums often have some sort of crank generator. The kids invariably compete to see who can make the light brighter.

As for an interesting magnet experiment, just drop a niobium "super" magnet down a narrow, non-magnetic metal tube. Aluminum arrow shafts work well. Let the kids compare how long it takes for the magnet compared to a non-magnet of equal size and weight.
We do that very thing at the moment with a magnet and a copper tube but the kids seemed rather underwhelmed. They like things that move and flash. Unfortunately the feedback has often been "the drones lab is cool but the power electronics lab is boring". I suppose it's difficult to convince children of the merits of switch mode circuits vs linear circuits :rolleyes:
 

jpanhalt

Joined Jan 18, 2008
8,134
Kids definitely like to do, rather than watch, and if there is anyway to introduce competition, it helps.

Maybe a bicycle driving a generator with a variable load. See how tired they get or who can drive the biggest load?
 

djsfantasi

Joined Apr 11, 2010
5,705
Lightning!

Make sure your display area is dark. Separate from the outside with black drapes (treated with fire retardant. Roscoe is one brand)

Build a DIY Van de Graaf generator. I’m not recommending this Instructables link, but there are build instructions on the Internet

Build a plexiglas cube. To hold the device. And build a robotic arm with the electrode.

That way, the students can use the robotic arm to move the electrode to make their own lightning. You could possibly use two such arms.
 

Tonyr1084

Joined Sep 24, 2015
3,680
Younger ones may be thrilled by seeing how a red, blue and green light can create all the colors of the rainbow, including white. Three colored spotlights shining on an old movie screen; each light controlled by a knob to control brightness.

Older kids may be interested in lasers (but keep tight control over where the beam is pointed, along with any possible reflected incidental beams).

The old Theremin Music Maker, an instrument you play by NOT TOUCHING it. Here's a "How To" that explains it pretty well, and the following video shows a professionally built unit played by a professional.
 

Thread Starter

TechWise

Joined Aug 24, 2018
56
Thanks for all the ideas folks. I like the ones with the magnets as we need to be a bit careful not to encoach on the areas covered by the other research groups. For instance the High Voltage team already wow them with a tesla coil and a Van de Graaf. There's a photonics group that show them high power lasers, an ultrasound group that get them looking for defects in steel sheets. Our area is very much power electronics, machines and drives.
 

Teljkon

Joined Jan 24, 2019
112
when in doubt blow things up blue laser some balloons. What about those race cars that run on a track do those but use a hand cranks. Then have them design0 there own hand cranks.
 

Wolframore

Joined Jan 21, 2019
1,324
How about a hand crank that powers an electromagnet that picks up metal from a junk pile. Designed with a decent flywheel and the kids can see how much they can generate. Add large 7 segment display that shows how much weight they’re picking up. Challenge them by asking them how much power can you generate.
 

atferrari

Joined Jan 6, 2004
3,489
How about a hand crank that powers an electromagnet that picks up metal from a junk pile. Designed with a decent flywheel and the kids can see how much they can generate. Add large 7 segment display that shows how much weight they’re picking up. Challenge them by asking them how much power can you generate.
Hard for a common kid saying so.
It should have clear before, what power is to eventually quantify an hypotetical amount.
 

Tonyr1084

Joined Sep 24, 2015
3,680
Too often we think of power as "POWER!" But the truth is that power comes in many forms. Aside from impressive displays of very powerful things, there is the smaller side of power. Given that much of micro-electronics is reducing the need for power, why not include that in your display. I've worked with components that were VERY static sensitive. As little as 50 volts static charge could blow the device.

In keeping with the display ideas, how about a clock powered from a potato or from oranges - or other items? You can even have a give-away where you give away a small number of kits such as the one in the video.

 
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