Using naturally occurring electricity to create beautiful public spaces - MA Material Futures runner up Riina Õun explains the science behind her project.
Piezoelectricity is the electrical charge that accumulates in certain solid materials (such as crystals, certain ceramics, and biological matter like bone) in response to applied mechanical stress. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. Essentially, piezoelectricity is generated by everyday movements like the vibrations caused by footsteps - often it is not utilised and so goes to waste. For my project I investigated the generation of light through piezoelectricity.
My goal was to create a light generated by the side-energy of our everyday life, which is currently not utilised and therefore goes to waste.
Rochelle salt (Sodium Potassium Tartrate Tetrahydrate) was one of the first known materials found to exhibit piezoelectricity, so I selected this material to use in my experiments. The salt crystals can be cooked at home, and once I had created some crystals I connected them to a multimeter that I used to test the amount of piezoelectricity I could create through kinetic energy. Tapping the crystal measured the maximum 0.5 volts. Whilst this was not enough to illuminate my 3 volt LED lamps I was still able to use the salt crystals for decoration.
I embedded the rochelle salt into my two-tier pavement slabs along with Swarovski upcycled crystals and LED lights. The crystals served to make the slabs attractive, diffusing and reflecting the light from the LEDs. Applying pressure to the top tier of the paving slab causes the LED lights, situated under the crystals, to light up.
In the future I see the environmentally sustainable piezoelectricity taking over busy streets in the megacities of the world.
Starting with the pavement leading to Swarovski Crystal World I would like to see the piezoelectric pavement making its way to the busy streets of large cities. It would offer an extra light source, a pleasant surprise and a beautiful, decorative design. In the future I see the environmentally sustainable piezoelectricity taking over busy streets of the megacities of the world.