Most people have experienced the simple pleasure of giving themselves a chipmunk voice with helium, but there's also a gas ...

Besides an ideal source of lift for your balloons, helium is also ideal for making your voice high and squeaky, but how does ...

Helium is much lighter than air, so sound waves move much faster through the gas. This amplifies the higher frequencies in your voice. The gas sulfur hexafluoride works in the opposite way.

When you speak, your voice reaches your ears in two ways: through the air and through your body. Normally, we hear sounds through air conduction, where sound waves travel through the air ...

Save guides, add subjects and pick up where you left off with your BBC account. A nail hit hard with a hammer will have a lot of energy so will cause a strong vibration. This means the sound waves ...