The Green Team has a number of events during Earth Week, April 21-27

Check out the Green Team's schedule for Earth Week, April 21-27! If you can, please participate and have fun with it! Thanks!

Dramatic visual evidence for climate change - glaciers

Check out this TED talk by James Balog, a photographer who spent some three years producing time lapse movies of what some glaciers are doing as temperatures rise...amazing work! On Netflix, you can watch a documentary about how he did this, called Chasing Ice.

Sir Michael Berry to visit with ETHS students and faculty April 10

A rare opportunity exists for ETHS students and faculty next Tuesday, April 10, at Northwestern.  The Physics and Astronomy Department is hosting Sir Michael Berry, a world-renown physicist who dabbles in a wide array of topics, and has made a number of big theoretical and mathematical discoveries in his career (must have done something cool to be knighted!). He is giving public talks every day next week, and you can see the schedule.

Tuesday, the department confirmed that from 4:15 – 5:15 pm, in room F160, any ETHS student or teacher is welcome to meet privately with the professor. Refreshments will be served by NU, and you can have a chance to meet one of the ‘big shots’ of science and ask him anything you might be curious about, including his views on where STEM fields are headed and what the big mysteries are for your generation to tackle! He has received numerous international awards for his work, which is largely in quantum phenomena and optics, and has some 400 publications. Again, this doesn’t happen every day, so please consider going to this if interested.

Room F160 is on the first floor of Technological Institute (main science and engineering building), the huge whitish building on Sheridan Road near the Noyes Street stoplight and just south of the tennis courts. One can park in the lot across the street, or any other lot, after 4 pm without a permit, and there should be some street parking by that time. As you walk toward the U-shaped building, go into the entrance on your right, which goes directly into the F-wing and Physics Department. Just walk straight as you enter and F160 is down that hallway, so should be very easy to get to. Please let Doc V know if you have any questions. Thanks! 

Scholarship opportunity

The Science Department has the $1000 Carol Beatty Scholarship. The application is here. It is for interest and investment in science.

The Society of Women Engineers scholarship is due April 10. Application is here.

Wednesday

Periods 3-4, 8-9:

VERY sorry to miss you again...please hang in there!
Check out an example of this Faraday's law where a second force is present, such as gravity. This is going to be mathematically the same as n old friend, air friction, from last year; this will be a terminal velocity thing. Be sure to get some notes on it.
As a bonus problem, you can try the last problem in the B dA dt Induction packet, page 9 (nicknamed 'the hardest ever').

Then, check out the second version of Faraday's law, and how we can change magnetic flux. This is where the area stays constant (just have a metal hoop sitting there) and we change the magnetic field. This is physically a different process where a moving magnet creates (i.e. induces) an electric field. This is true E&M - so a moving charge turns on a B-field, and a moving magnet (or any type of changing B-field) turns on an E-field. This video is on induced voltage = emf = AdB/dt.

For some initial practice, try the 1978 and 1999 AP problems (p. 5, 7) in the AdB/dt packet in the EM Induction folder. (called A dB dt Induction.pdf)

Tuesday

Periods 3-4, 8-9:

EM induction is all about magnetic flux. Remember Gauss says electric flux = (E-field)(area), so magnetic flux = (B-field)(area) = BA. And one thing we will see with a number of devices is that if there is any change in magnetic flux, then a voltage is turned on if the object is a conductor. This is like when you move a magnet through a solenoid, and voltage turns on. If the magnet is till, the voltage turns off. We'll figure out why this is, but nowadays we call this rule Faraday's law:
     induced voltage = "electromotive force" = emf = d(BA)/dt

So the faster you move a magnet through a wire loop or solenoid, the more voltage is induced. Faraday called this 'electromotive force,' or emf, and many still use this term. There are 2 main ways to change flux:
i) have a constant B-field but move a metal loop (changes the area where the magnetism goes through), BdA/dt
ii) hold a metal loop still (constant area) and change the magnetism, AdB/dt

Please check out the two videos:
One common, and perhaps strange, example of magnetic flux can be seen here.
Description and examples of emf = BdA/dt can be found here.

In the packet you get in class, for flux please try Ch. 27 #11, 13, 14 (p. 5). A packet for emf = BdA/dt is in our EM Induction folder here. See if you and a study group can talk through the 1981 problem on page 5 of the packet.


Period 6:

We are starting static electricity. The biggest example is lightning, which we may see later today with some storms coming in. Check out this video, and take notes, on some ideas as to how lightning works.

Then, search on YouTube 'static electricity.' There will be all sorts of video options. View a few and look for your favorite demos/experiments to try with static electricity. Write down your 2-3 favorites that you'd like to do in class, and be sure to include materials and procedure. We'll check them out tomorrow and plan on doing some, and figure out how it all works!

Tonight, read and take notes on pages 541-548.