Sneakers squeak on basketball courts. Physics explains why

air pressure: The force exerted by the weight of air molecules.

frequency: The number of times some periodic phenomenon occurs within a specified time interval. (In physics) The number of wavelengths that occurs over a particular interval of time.

physicist: A scientist who studies the nature and properties of matter and energy.

pitch: (in acoustics) The word musicians use for sound frequency. It describes how high or low a sound is, which will be determined by the vibrations that created that sound.

pressure: Force applied uniformly over a surface, measured as force per unit of area.

range: The full extent or distribution of something. For instance, a plant or animal’s range is the area over which it naturally exists.

silicone: Heat-resistant substances that can be used in many different ways, including the rubber-like materials that provide a waterproof seal around windows and in aquariums. Some silicones serve as grease-like lubricants in cars and trucks. Most silicones, a type of molecule known as a polymer, are built around long chains of silicon and oxygen atoms.

sound wave: A wave that transmits sound. Sound waves have alternating swaths of high and low pressure.

tune: (in engineering) Adjust to the right level.

ultrasound: (adj. ultrasonic) Sounds at frequencies above the range that can be detected by the human ear. Also the name given to a medical procedure that uses ultrasound to “see” within the body.

wave: A disturbance or variation that travels through space and matter in a regular, oscillating fashion.