radioactivity -...
TRANSCRIPT
7 Radioactivity.notebook May 29, 2017
RadioactivityStrong Nuclear Force...
Attractions between particles in the nucleus.
proton protonproton neutronneutron neutron
Heavy nuclei can become unstable if the strong nuclear force cannot overcome the electromagnetic repulsion
RadioactivityThe Spontaneous disintegration of atomic nuclei through the emission of particles
Henri Becquerel
Marie and Pierre Currie
Discovered it in 1896
Isolated in 1898 two new radioactive elements Polonium and Radium
Governed by the Weak Nuclear force. This is why the nucleus doesn't just explode, but breaks into specific pieces.
7 Radioactivity.notebook May 29, 2017
Ernest Rutherford
Named the three types of radiation
AlphaParticlesαBeta Particles βGamma Rays γ
Particle Description Charge
Alphaα
Helium nucleus (2 protons 2 neutrons)Fast but travel short distancesStopped by aluminum foil
+
Beta β
ElectronsVery High Speed (close to light)Need several mm of aluminum to stop
Gamma γ Electromagnetic Radiation Various speedsNeeds 2 km of air or 30 cm of lead to stop
7 Radioactivity.notebook May 29, 2017
Charged particles are bent by a magnetic field
Radioactive source
Can measure radioactive particles with:
Photographic FilmCloud chamberBubble ChamberGeiger Counter
7 Radioactivity.notebook May 29, 2017
Measuring Radioactivity
R = N t
1 Cu = 3.7 x 1010 Bq