July 2 – Second Half of the Year Day

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• nDon you know what an element’s half-life is? It is the amount of time itn takes for half of its unstable atoms to undergo radioactiven decay.

  Most elements are stable, not radioactive. But somen elements (and some isotopes) are radioactive and spontaneously emitn energy or particles.

  For example, atoms of the radioactiven element radium can “decay” by emitting either alpha particles orn carbon-14 nuclei – and thus become another element (either radonn or lead). We can never predict exactly which particular radium atomn will decay, exactly when, but the the decay rate for a bunch ofn radium atoms isn predictable; radium’s half-life is the amount of time it takes forn half of the atoms in a sample of radium to decay.

  Radium-226n has a half-life of about 1,600 years.

  Learn more aboutn radioactivity by watching this video.n The Second Half of the video talks about half-life. 

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  nDon some half-themed puzzles: Here‘sn one in which the Second square is cut in Half.nAnd heren is one called Half a Barrel.

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• nReadn Give Me Half!,n by Stuart J. Murphy, and then try the trick of how to share food fairly:n one person cuts the food in half, and the other person chooses hisn or her half. 

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  nReadn Half Magic,n by Edward Eager. 

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nAnniversarynof the beginning of the “GoldennAge of Airships”
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• nJulyn holidays

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• nJulyn birthdays

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• nHistoricaln anniversaries in July

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• nAugustn holidays

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• nAugustn birthdays

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• nHistoricaln anniversaries in August

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