The notes are here and the wording of the explanations is quite important.
We also discussed whether or not we are at the centre of the universe's expansion. This is not on the syllabus but it's nice to understand.
We then considered what could happen to the universe in future.
Doppler effect, red shift
Classwork
We went over key ideas about the Doppler effect from your HW.
I demonstrated this page which is really useful for seeing the cause of the Doppler efect.
We discussed the doppler effect for light, and 'blue shift' and 'red shift'.
You started to watch this video which shows how the theory of the Big Bang developed. More on this next lesson.
Doppler Effect
Classwork
I gave out the list of stuff you need to know for the end of year exam.
We started to make notes on the Doppler effect, and we went to the field where I demonstrated it using sound.
We then used this website to take some measurements of frequency and wavelength for a stationary source, and then moving towards and away from the observer.
We when started to look at the doppler effect on light, and got up to defining 'blue shift'.
Test, Proportionality
Classwork
We went through the test on waves.
You made notes on proportionality, and different ways to test for it.
Test
Classwork
We did some revision, then did the test on Waves.
Homework
No homework.
Sterilization
Classwork
We watched this video which shows a gamma sterilization plant, and discussed various aspects in detail.
We also made notes on radiation film badges.
Homework
Revise for a test on waves on Thursday.
EM Applications
Classwork
You did Q1 on P75 and I demonstrated interference with reflected waves using sound.
You adedd to your notes on x-rays and CT scans, having already watched this video which gives a nice explanation.
You then made notes on radiotherapy, and how damage to healthy tissue is minimized. We watched this video which shows x-rays being used for radiotherapy.
You made notes on sterilization, and the particular use of x-rays and gamma rays because they are so penetrating.
Homework
You might want to watch this video which shows a gamma sterilization plant.
Revise for a test on waves next Thursday.
Diffraction
Classwork
You did the questions on diffraction on P73 and we went through them together.
I demonstrated the diffraction of a laser beam through a narrow slit.
Homework
Choose a diagram you like from here and add it to your notes.
In particular, please draw force diagrams for the skydiver: A) just as they leave the plane B) as they are falling (but not yet at terminal speed) C) when falling at terminal speed D) just after opening their parachute and E) after they have reached a new terminal speed with the parachute open.
Leave some space next to each of these diagrams for us to add notes next lesson.
PLEASE JUST MAKE YOUR ARROWS LONGER AND SHORTER like on the second website, rather than fatter and thinner as well (like the first site does).
Terminal Speed
Classwork
You predicted how a feather and a rubber would fall when dropped.
We did this experiment using a slow motion camera and compared the results to the predictions. You decided that air resistance caused the two objects to fall differently.
We made notes on nuclear fusion, and just got up to the point where the neutrons produced in fission can go on to cause a chain reaction.
If you missed the lesson, watch this video and see P222-3 of the textbook.
We also looked at some equations for nuclear fission, and checked if the number of protons and neutrons was conserved.
Homework
No homework.
Test
Classwork
We did the test.
Homework
No homework.
Deflection in fields, recap
Classwork
We made notes on deflection of alpha, beta and gamma in electric and magnetic fields.
We also made brief notes on the use of gamma for medical tracers.
We put some people in the hot seat and asked them questions from this topic.
Homework
Revise for test next lesson.
Radioactive Dating
Classwork
We went over carbon dating and did some examples.
Homework
Can't remember - didn't write it down at the time....
More half-life
Classwork
We went over the HW.
We made notes on the definition of half-life, defined 'activity', and contrasted activity with count rate.
You did an activity with dice to model radioactive decay.
We plotted graphs of activity and dice remaining - the activity graph was messy, but the dice remaining graphs showed nice decay curves.
You calculated the 'half-life' of your dice.
WE AGREED TO DO A TEST ON THIS STUFF ON TUESDAY 13TH OCTOBER.
Homework
Make notes on radioactive dating, using this video (which is just about carbon dating) and P219 of the textbook.
Bring your notes to next lesson.
Half-life
Classwork
We did a starter question to practise half-life calculations.
I did a demonstration (with some useful assistants) to show you the decay of an isotope of protactinium.
The results are here (I removed the first minute or so as the layer was still separating out) - you can also compare with the other group's results which are very similar.
We also refreshed your Excel skills when collecting and processing the data to get the corrected count rate in counts per minute.
Homework
Answer the questions on P217 and hand in before registration tomorrow morning.
Uses of alpha, beta, gamma
Classwork
We went through key uses in detail - alpha in smoke alarms, beta in paper manufacture, gamma in radiotherapy, sterilization and leak detection.
We also practised our languages a bit.
Homework
Watch this video and use P216-7 to make notes on half-life.
Bring your notes to next lesson.
Background radiation
Classwork
We identified the deacy processes in a decay chain.
We went through the HW, classifying sources of background radiation as natural or man-made.
I'm trialling a web-based whiteboard - you can now see notes from lessons here. We'll see if it's any good...
We started the questions on P213 and went through Q1.
Homework
Research one use each for alpha, beta and gamma radiation.
