The precious noise cancelling headphones that every seasoned traveller carries in their bags are actually quite an incredible piece of technology. These headphones work by listening via microphone to the surrounding sound waves, and then creating and playing the exact opposite waves, in order to cancel them out. This process is quick, but not instant, which is part of why noise-cancelling items work best on constant noises, like airplane engines or traffic, but might struggle more with sudden noises like babies crying. You may notice a pressure like feeling in your ears when you first put noise cancelling headphones on, like when you want to ‘pop’ your ears in an airplane. This is because your brain is picking up both the original sound waves, and the opposite sound waves made to cancel them out, putting twice as much pressure on your inner ear. These headphones aren’t perfect, but they do manage to block out roughly 70% of noise, and can really improve both the listening and travelling experience.