A Summer Challenge >>> Some of you were interested in actually sending your own radio signals - I have no idea how -- but here are some sites that give instructions, and of course you can google your own:
Either of these directions involves buying several parts, an oscillator and a transistor and a board. Let me know if you get it going. And have a wonderful summer.
Light in Slow Motion (Remember in our textbook, it said that light is both a particle and a wave- if you watch the pulse of light in the Coke bottle, you can visualize how this is so. See it as a particle, a pulse, and then see it as a wave.)
On Monday we will probably be able to finish the radios, but likely we will have to wait till the following week to try them out. To make a homemade "ear bud" bring a tin can to class, and if you have a good magnet (neodymium) bring that. An old telephone receiver would be good, if you have one to donate.
Thank you for your patience in class yesterday; I think our project actually went as good as it could, kinda like a first draft on a writing project, and so if it did not go well for you, it probably will go much better when we do it over. I have never done this before myself, but I think this will be a fascinating and enlightening project; radio and television has always been just "magic"- what I mean is it made no sense to me. Hopefully, we will start to get glimmerings of how it works.
Here is a video from 1943--that's right in the middle of WWII!-- explaining how radio is broadcast. In your notes, copy the flow chart near the end (at 8 minutes) that shows the steps, even if you don't entirely understand. A Blast from the Past!
Here is a video that talks through all the steps of building a crystal radio; however, it is not precisely the same as the version we are making. We will be building the capacitor next; that is the paper towel tube with the aluminum foil/paper slider, so pay special attention to that. So, somehow get a hold of a paper towel tube by next Monday!
We will also need to find various sound amplifiers, like do you have an old corded phone in your junk pile? We may need to build some earphones, requiring strong magnets (neodymium)
This is a schematic of what we are going to build -- it's like a code --can you figure any of it out?
The parts are as follows: antenna, capacitor, coil, earphones, diode. (A diode is a little bitty part that makes all the electrons go in one direction only--like a one-way street.) We are missing a ground wire.
TEXTBOOK READING: If you finished watching the NASA videos having to do with the electromagnetic spectrum (from the last blog) , you may skim over chapter 13, section 2 from your textbook, and proceed to reading section 13.3 (chapter 13, section 3) pages 403-406 ONLY on radio and television communication.
If you did not yet watch all the videos from last blog, time to do so.
Homework is watching some short videos. This site has a playlist of 8 short videos on Electromagnetic Radiation. Watch all 8 (I have only watched the first one yet, but I think it must be good, 'cuz it's NASA,?) Maybe you should take a break half-way through. http://missionscience.nasa.gov/ems/emsVideo_01intro.html (
(sorry about the missing link -- computer problems! It's 32 minutes total time, but if you can only do the first half, that's fine. One thing to understand from these videos is how much we have been able to learn about the universe by "tuning in" to all the wavelengths of EM radiation.) Tak
The parts are as follows: antenna, capacitor, coil, earphones, diode. (A diode is a little bitty part that makes all the electrons go in one direction only--like a one-way street.) We are missing a ground wire.
