12a work Friday 23rd November

Hello Y12, sorry I was not there for our lesson today - I will be back P4 for 12b.
12a work is as follows;
1. Research emission and absorption spectra for elements.  Make notes on what they are and what they show - this is a tricky idea but it relates to the absorption and emission of photos of particular colours between energy levels of atoms as we showed in the models we did in class with Starburst.   Bring you notes and diagrams to the lesson next Friday for us to discuss
2. What is the photoelectric effect what was observed and how did Einstein explain it with photons? Another tricky but key idea for us to discuss on Friday - can you come up with a model to explain what is going on?

3. What are the energy levels in a hydrogen atom, and why is n=1 labelled as negative?

Thanks, Ms Hamnett

Stargazing Oxfordshire – astronomy evening

Stargazing Oxfordshire – astronomy evening

 

Find out more about research in astrophysics from professional scientists, and observe the night sky with your local community astronomers.

Tuesday 20^th November 2012 – entrance from 6.00pm

More information and booking can be found here: http://www2.physics.ox.ac.uk/events/2012/11/20/stargazing-oxfordshire. We will be running similar events in January and March.

Particle physics tips

• KNOW YOUR FORMULA SHEET
• Hadrons feel the strong nuclear force and are made of quarks
• Baryons are made of three quarks, mesons are made of two quarks (a quark and antiquark)
• Protons are uud, neutrons are udd
• Baryons eventually decay into protons (protons are the only stable baryon)
• Neutrons decay into a proton, an electron and an antineutrino (beta minus decay)
• Protons decay into a neutron, a positron and an neutrino (beta plus decay)
• Hadron – heavy and strong  Lepton – light and weak
• Leptons have a lepton number of 1 (or minus 1 for antiparticles) and lepton number is conserved
• Leptons can change into other leptons during decay via the weak interaction
• Strangeness is conserved in a strong interaction
• K mesons are strange particles (containing a strange or antistrange quark) formed through the strong interaction and decay through the weak interaction into π mesons, muons and antineutrinos
• π  mesons Charged π mesons decay into muons and antineutrinos (or antimuons and neutrinos), π zero pions decay into photons
• Muons decay into electrons and antineutrinos (or antiparticles)