Hertz is the number of cycles per second in an oscillating wave form. So 60Hz has 60 identical cycles in 1 sec. An Ampere (amp, or A) is the amount of electrons (or charge) that flow past a certain point in one seconds. So amperes are Coulombs/second.
The most and the least painful places to get a tattoo. Shoulder. The shoulder is the least painful tattooing site for two main reasons. First, because in this area there is a greater amount of muscle and second â nerves are not so much sensitive as in other nooks of the body. This area is often the most used and first timers tend to opt for them.
What makes tattoos so long-lasting is they're so deep â the ink isn't injected into the epidermis (the top layer of skin that you continue to produce and shed throughout your lifetime). Instead, the ink is injected into the dermis, which is the second, deeper layer of skin. Dermis cells are very stable, so the tattoo is practically permanent. Tattoos used to be done manually â that is, the tattoo artist would puncture the skin with a needle and inject the ink by hand. Though this process is still used in some parts of the world, most tattoo shops use a tattoo machine these days.