applied in electrochemical sensing via the in-situ surface modification of disposable screen printed carbon electrodes (SPEs) with various metal and carbon sources. Hazards Sparks can be hazardous to people, animals or even inanimate objects. Electric sparks can ignite flammable materials, liquids, gases and vapors. Even inadvertent static-discharges, or small sparks that occur when switching on lights or other circuits, can be enough to ignite flammable vapors from sources like gasoline, acetone, propane, or dust concentrations in the air, such as those found in flour mills or more generally in factories handling powders. Sparks often indicate the presence of a high voltage, or "potential field". The higher the voltage; the farther a spark can jump across a gap, and with enough energy supplied can lead to greater discharges such as a glow or an arc. When a person is charged with high-voltage static-charges, or is in the presence of high-voltage electrical supplies, a spark can jump between a conductor and a person who is in close enough proximity, allowing the release of much higher energies that can cause severe burns, shut down the heart and internal organs, or even develop into an arc flash. High-voltage sparks, even those with low energy such as from a stun gun, can overload the conductive pathways of the nervous system, causing involuntary muscle-contractions, or interfere with vital nervous-system functions such as heart rhythm. When the energy is low enough most of it may be used just heating the air, so the spark never fully stabilizes into a glow or arc. However, sparks with very low energy still produce a "plasma tunnel" through the air, through which electricity can pass. This plasma is heated to temperatures often greater than the surface of the sun, and can cause small, localized burns. Conductive liquids, gels or ointments are often used when applying electrodes to a person's body, preventing sparks from forming at the point of contact and damaging skin. Similarly, sparks can cause damage to metals and other conductors, ablating or pitting the surface; a phenomenon which is exploited in electric etching. Sparks also produce ozone which, in high enough concentrations, can cause respiratory discomfort or distress, itching, or tissue damage, and can be harmful to other materials such as certain plastics. See also Corona discharge Electrical breakdown Paschen's law Static electricity References External links Szikrakisülés (1)...(4) Electric spark (1)...(4). Videos on the portal FizKapu . Electrical breakdown