WEBVTT - How does a chicken's egg get its shell?

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<v Speaker 1>to brain Stuff from how stuff marks dot com where

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<v Speaker 1>smart Happens. Hi Am Marshall Brain with today's question, how

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<v Speaker 1>does a chicken's egg get its shell? I mean, does

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<v Speaker 1>the chicken make this shell and then fill it with

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<v Speaker 1>an egg white and a yolk? Or does it make

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<v Speaker 1>the egg white and the yolk and then wrap a

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<v Speaker 1>shell around it or what? It turns out that the

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<v Speaker 1>chicken has little to do with the formation of the

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<v Speaker 1>eggs shell. The egg actually grows the shell around itself.

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<v Speaker 1>It does this using a process that's also seen in

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<v Speaker 1>bones and seashells. Around the egg, there's a membrane, and

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<v Speaker 1>on the membrane there are evenly spaced points where columns

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<v Speaker 1>of calcite form. These columns stacked together side by side

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<v Speaker 1>to form the shell. The calcium columns grow like crystals,

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<v Speaker 1>and they fuse together to make a complete shell. The

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<v Speaker 1>calcite is basically floating in solution around the shell. Once

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<v Speaker 1>the membrane is put in place and it deposits on

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<v Speaker 1>the membrane to form that crystal, the egg grows its

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<v Speaker 1>own shell. For more on this and thousands of other topics,

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