This is a simple demo to help visualise the effect of resonance, but it also makes a nice alternative Christmas decoration. It has three different length pairs of vertical rods with weighted baubles on the top and when you pull one rod only its partner will move. The Bloodhound SSC quote below explains the importance of understanding resonance and its effect if you get it wrong!

"This simplified (CFD) model took around a week to solve and gave us a more accurate prediction of the drag generated by the airbrakes, as well as giving us an approximation of the frequencies of the flow around the car, so we know roughly how stiff the airbrake and rear structure needs to be in order to avoid those frequencies, which might otherwise resonate and shake themselves to bits!" Chris Hannon - Stress/Research Engineer


- Senior hacksaw

- Pencil and tape measure

- Centre punch and hammer

- Metal file

- Pliers, spanners and/or a small adjustable

- Bench or pillar drill

- Drill bits

- Laminator (optional)


- Floor lamp base (http://www.argos.co.uk/static/Product/partNumber/4...

- 25mm x 25mm steel bar - 50cm

- M4 or M5 threaded rod - 3m (or can be pre-cut to lengths of 2x 65cm, 2x 50cm and 2x 35cm)

- 12 nuts and 6 spring washers (either M4 or M5 on which sized rod you go for)

- Large nut, bolt and washers to suit the floor lamp base

- 6 coloured Christmas baubles (plastic) or wooden balls

- Picture of Bloodhound SSC (optional)

- Laminating pouch (optional)

Step 1: Metal Cutting and Drilling

- Use a senior hacksaw and cut your metal bar to 50cm, as most are supplied in 1m lengths. Use the metal file to deburr it and remove any sharp edges

- Carefully mark the centre using the punch and hammer, then mark the 6 remaining points. I started from the edge and worked inwards starting 0.5" from the edge, followed by 3" and then 3". Then I repeated it from the opposite end and you get a nice even spread for the rods. I always add a cross using the pencil to make the mark easier to see

- The threaded rod also usually comes in 1m lengths, which makes it easy to cut them to the correct length. Cut the first one in half, then mark the other two at the 65cm mark and cut them. That way you'll end up with two lengths of 50cm, two of 65cm and two of 35cm

- Drill the centre hole according to the size of your lamp base and bolt you're planning to use. Then drill the 6 smaller holes all the way through the metal bar. Deburr the metal bar

About This Instructable




Bio: Science Fiction. A precursor to science fact.
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