Sound Waves by Connor

            This week in Physical Science, we are learning about sound. Sound is energy that is carried by waves. Many things affect how these waves travel, such as density and temperature. Our outer ears are what pick up sound and send it to our brain. Human ears have many parts, such as the eardrum, ear canal, cochlea, and smaller middle ear parts. I learned that loudness is actually how humans perceive intensity, which is the amount of energy in a specific time and place. Humans actually know many things about sound instinctually, such as having to increase loudness when wanting to talk to someone farther away. Humans can only hear things at a certain pitch or frequency. Our range is from 20Hz to 20,000Hz. Different animals have different ranges of pitch that they can hear i.e. dogs can hear much higher than humans can and this is why we can’t hear dog whistles.

●     I learned that when you hear something loud and it hurts your ear, that is when the loudness is at or above 120 dB(decibels). Decibels are what we use to measure loudness.

●     The Doppler Effect happens when something that is making a sound passes you. It makes the same sound coming up towards you, but then it changes pitch after it passes you, even though the pitch that something is making hasn’t changed at all.

●     One more neat thing about how sound travels is that different mediums make sound travel faster or slower. Sound travels at 347 m/s in air, while in water sound travels at 1498 m/s which is a much faster pace. In our ear, we have liquid in it to help sound travel faster.

What I find most interesting about sound is that even though we can’t hear many sounds, they are still there and can be heard by other animals. This fascinates me because if I can’t hear a sound or I can’t see something, a lot of times I will think nothing is there, when in fact there could be something there. Examples of things we can’t hear are things like a bat’s echolocation or a nuclear bomb test. Kind of makes myself wonder about what things the government may be doing without our knowledge, even though I’m sure many people have pondered that. A good question to take away from this might be ‘how can I experiment with different pitches and sounds at home?’