Beauty in Hidden Forces
Matthew Lam
Award: Top 100
Award: Honorable Mention for Aesthetic
School: maine east high school
Teacher: jan wieczorek
Category: Contrived
Photo #21349
Beauty in Hidden Forces
In my photograph, I placed an ionic solution of sodium sulfate within a petri dish. Ionic solutions consist of charged particles that are easily separated by the ion-dipole interactions present between them and water molecules. Normally, these sodium and sulfate ions would disperse themselves evenly throughout the solution. However, I used a power supply to create a voltage across the solution to induce the motion of the charged particles between two carbon rods. Underneath the petri dish I placed a strong magnet, whose magnetic field caused the charged particles to experience the Lorentz force. At one end, the particles swirl in a clockwise direction, while the other is counterclockwise, as predicted by the right hand rule.
The variety of colors within the solution can be explained by electrolysis and acid/base chemistry. The large voltage between the carbon rods causes water molecules to break apart. At the cathode, hydrogen gas is liberated, causing a surplus of OH- ions, which in turn causes the solution to become locally basic. At the anode, oxygen gas is liberated, causing a surplus H+ ions, which makes the solution become locally acidic. The pH changes are then visualized using an universal indicator, which causes the solution to turn red for acidic and blue for basic. The beautiful swirling patterns are a result of alternating the voltage slowly between the two carbon rods. The cathode is identifiable in this photo due to the stoichiometric ratio that reveals that hydrogen should be liberated at twice the rate of oxygen during electrolysis.
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