Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff,
Speaker 1: Lauren Vogel Bomb Here. Have you ever noticed how after
Speaker 1: a big snowfall, the landscape gets very quiet and everything
Speaker 1: looks like it's covered in that insulation that you find
Speaker 1: in the walls of houses. Things that had a distinct
Speaker 1: shape before wheelbarrows, mailboxes, parked cars all become muffled lumps,
Speaker 1: and the ambient noise were also used to is suddenly gone.
Speaker 1: Some of this has to do with the fact that
Speaker 1: the heavy snow can result in folks staying inside, cutting
Speaker 1: down on traffic noise and the sounds of kids playing.
Speaker 1: But there's something else too. Fresh snow actually is kind
Speaker 1: of like nature's blow in insulation. Snow makes everything it
Speaker 1: falls upon looks so lumpy because each snowflake is an
Speaker 1: irregular shape, a six sided crystalline structure that doesn't lend
Speaker 1: itself to stacking neatly atop other snowflakes. As billions of
Speaker 1: snowflakes fall on top of one another, they don't merge
Speaker 1: together and flow off of the landscape like rain does. Instead,
Speaker 1: they pile up on each other like a bunch of orgamy,
Speaker 1: a creating a material that has lots of tiny holes
Speaker 1: between each flake. This porous material smooths out all the
Speaker 1: sharp edges that usually make the things that snowfalls upon
Speaker 1: distinguishable from each other, and those little nooks and crannies
Speaker 1: between the snowflakes allow sound waves to enter, but then
Speaker 1: strip them of their energy as the waves make their
Speaker 1: way through that fluffy material. The sound travels in mechanical waves.
Speaker 1: If you've ever heard the tagline from the movie Alien
Speaker 1: in space, no one can hear you scream. That's because
Speaker 1: space is relatively empty of stuff, and in order for
Speaker 1: something to make noise, physical molecules of stuff, be they gaseous, liquid,
Speaker 1: or solid, must be jiggled around in order for the
Speaker 1: sound waves to be transmitted. A temperature also affects how
Speaker 1: quickly waves can move. They speed up in warmer weather
Speaker 1: and slow down when it gets cold. Not only can
Speaker 1: sound waves in cold weather be a little sluggish, but
Speaker 1: falling snow can interfere with them, making sounds and a
Speaker 1: winter wonderland seem muffled. A blanket of fresh snow also
Speaker 1: does a lot to dampen noise. The absorption of sound
Speaker 1: is measured using a scale called sound absorption coefficient. Alpha,
Speaker 1: which measures how well a material absorbs sound on a
Speaker 1: scale from zero to one. The sound absorption rating for
Speaker 1: snow is between zero point five to zero point nine,
Speaker 1: which means, at its most effective, a few inches of
Speaker 1: new fallen snow provides an impressive amount of acoustic insulation
Speaker 1: for a lot of different frequencies of sound. A one
Speaker 1: study published in twenty sixteen found that a couple inches
Speaker 1: of snow can absorb roughly sixty percent of ambient sound,
Speaker 1: but that quiet doesn't last long. The sound dampening air
Speaker 1: pockets and snow break down not long after snowfalls. That's
Speaker 1: because the shape of the delicate snowflakes changes pretty rapidly
Speaker 1: once they settle to the ground. As they begin to
Speaker 1: snowgle in together and or melt, the space between them shrinks,
Speaker 1: leaving fewer spaces for sound to travel and get trapped.
Speaker 1: In addition to that, oh once the sun hits the snow,
Speaker 1: a thin layer of ice forms on top almost immediately,
Speaker 1: turning that porous material that trapped noise in its first
Speaker 1: hours into a sound wave reflecting surface. And that means
Speaker 1: that it turns that silent landscape into a sort of amphitheater.
Speaker 1: So the next time you hear that hush of a
Speaker 1: new fallen snow, enjoy it. It probably won't last long.
Speaker 1: Today's episode is based on the article why does it
Speaker 1: get so Quiet after a Snowfall? On howstworks dot com
Speaker 1: written by Jesselyn Shields. The Brainstuff is production by Heart
Speaker 1: Radio in partnership with HowStuffWorks dot Com and is produced
Speaker 1: by Tyler Klang. Four more podcasts my heart Radio, visit
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