You deal with signal-to-noise ratio every day, even if you do not notice it. Scientists and engineers say signal-to-noise ratio is how strong a wanted signal is compared to background noise. When you try to listen to a friend in a loud room, your brain tries to pick out their voice from all the noise. A high snr means you can hear the message well. A low snr makes it hard to understand what is said. You see this in technology too. For example, in sound or pictures, a higher signal to noise ratio gives you better quality. The chart below shows how signal to noise changes in different places, like at home or in traffic, and how it changes what you hear.