White noise seems to be cropping up everywhere, from ASMR videos to lo-fi songs. It's also streamed from phones and speakers to help babies be put to sleep. But what is white noise, exactly? The static-like sound contains all frequencies on the sound spectrum at an equal intensity, all at the same time. This creates an output that's similar to that of an untuned radio. As it spans across multiple bands of sound, it can often be referred to as 'broadband noise'. Due to these multiple frequencies, white noise can mask other sounds which contributes to its calming and soothing nature – many use it for relaxation, focus and to help combat over-stimulation – some studies even suggest that it can help with sensory symptoms of ADHD. Many parents use white noise to help their babies stop crying and ease them into sleep, some theorise that it imitates a womb-like environment for the newborns. Not only this, but the noise can muffle out external sounds that could disturb the baby, helping them to stay calm and self-soothe. Not only can it help them fall asleep but stay in their slumbers for much longer! Some white noise machines even mimic heartbeats to provide extra comfort to infants.