Lord Kelvins Thunderstorm

Introduction: Lord Kelvins Thunderstorm

This is an instructable to show the fenomena of Lord Kelvin's Thunderstorm: to make an electric spark with just water.

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Step 1: Materials

- 3 Baulks (40/50/100 cm)

- 3 PVC tubes (2 x 65/43 cm)

- Rectangular Planter (15x50 cm)

- Empty ink tubule of a pen

- Transparant drinkpackaging

- Glue gun

- Metal & Copper wire

- Boults, Screws, Nuts

(All dimensions are just guidelines)

Step 2: Assembly 1 - Frame

Connect the three Baulks together. One as basis (50 cm) and the other two as Jezus' cross on top of this. The one-meter-baulk is vertically attached to the basis. The last baulk (40 cm) is added horizontal on a height 75 cm. This height is determined by the length of the diagonally added PVC tubes (next step).

At the end attach the frame to the inside of the rectangular planter.

We used a metal corner connection to construct the basis and a big screw to assemble the cross.

Step 3: Assembly 2 - PVC Cross

With one big boult and a nut the two same sized PVC tubes are connected to the middle frame. Through these PVC tubes a copper wire connects two 'coils' (see pictures) .

Step 4: Assembly 3 - Water Drip System


Make a hole on both sides of the drink packaging with the diameter of the leftover PVC tubes (45 cm).

Cut out half of the cylinder in the middle of the tube (Watch out to not make this bigger than the width of the drink packaging). Also make two small holes (diameter of the ink tubule), one at each end of the tube on the opposite side of the cut out part.


Glue the packaging to the horizontal baulk. Put the PVC tube through the packaging holes and also glue this together. Eventually connect two small parts of the ink tubule with the PVC tube through the holes at the end. These tubules will make a fast dripping water jet (try yourself what works, a small tap would work too).

Make sure everything is attached watertight!

Step 5: Assembly 4 - Wires&coil

To make sure the water will drip through the coils, the copper wire is strenghtened with the stiffer isolated metal wire. Now the coils are adjustable.

Also the coil at the bottem is glued to a plastic surface. Afterwarts we found out this was needed to contain the charge.

Step 6: Assembly 5 - Balls of Steal

To see the spark you need two surfaces between which the electricity will jump. Therefore two metal spheres are connected to the bottem coils. These spheres can be self made by wrapping a round object with aluminium foil and flatten the surface (see picture for our first and final prototype). By putting the spheres in a dark room, the spark will be better visual.

Step 7: Use It!

1) Fill the drink packaging with water.

2) Fine tune the dripping jet through the middle of the upper coil and onto the bottem coil.

3) Watch and hear the spark go from the one sphere to the other. We made a spark every 5 seconds! Place the sphere in a dark place to see the sparks even better.

!! Watch out when you have a pacemaker. High voltage sparks can be made. !!

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    2 Discussions

    This sounds really cool. Could you share a little more about the principle of how and why this works?


    Reply 1 year ago

    The process is based on the chance of the water being slightly more positively or negatively charged. When the waterdrops fall through the upper coil, one side becomes more positive And the other more negative due to the chance of a small difference in charge. When the water lands on the coil below, iT Will have an opposite charged of the Same water falling through the upper coil, only increasing the potential between the two sides because of the crosswise connection of the coils. This all Will also cause positively And negatively charged water particles to be Pushed/Pulled to the side which attracts them.
    Hope this will answer your question.