P7

P7

1. inside the atom

   • radiation
     • alpha
       • 2 neutrons
       • 2 protons
       • blocked by paper
       • short distance
     • beta
       • high speed
       • electron/proton
       • blocked by aluminium
     • gamma
       • dampened by lead
       • energy wave
     • ionisation
       • the reason radiation damages you
       • makes things irradiated
   • atom
     • nucleus
       • proton
         • charge=+
       • neutron
         • charge=0
     • electron
       • charge=-
   • radioactive decay
     • the reason atoms are radioactive
     • measured in becquerels
     • becquerels measure the rate at which half the unstable nuclei decay and emit radiation

2. atomic models

   • Plum Pudding
     • large ball of positive charge
     • small negative bits in it
   • nuclear model
     • nucleus in the middle
     • electrons in orbit

3. Nuclear fission

   • fission neutrons
     • when a nucleus undergoes fission it releases neutrons
     • two or three neutrons released at high speed
   • when the nucleus of a fissionable atom is struck by a neutron it splits into two smaller nuclei or roughly equal size and releases several neutrons