scaling the electromagnetic spectrum boxing out waves


Post on 16-Dec-2015




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  • The First Big Idea Scale describes matter and predicts behavior.
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  • The Other Big Ideas of Nano Structure of Matter Forces and Interactions Quantum Effects Size-Dependent Properties
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  • Other Big Ideas - continued Self-assembly Tools and Instrumentation Models and Simulations Science, Technology, and Society
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  • An Amazing Scale More than you can see
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  • Wavelength is the Key What we see is much less than what we get. Opensource Handbook of Nanoscience and NanotechnologyOpensource Handbook of Nanoscience and Nanotechnology. Illustration by Kristian MolhaveKristian Molhave
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  • 10 -7 = 0.0000001 = 100 nm Visible Light 390-750nm Nanoscale =1 - 100nm
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  • 10 -9 = 0.000000001 = 1 nm X-ray.01 to 10nm
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  • Waves Transfer energy without transferring matter
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  • Electromagnetic Energy Determined by wavelength and frequency. E = mc 2 c = 2.9979 x 10 8 m/s
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  • Dual Nature of Light Light is also photons (particles) Zero mass and zero rest energy Can be destroyed and created Can have particle-like interactions with matter
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  • Electricity and Magnetism Magnetism and electricity move together in the EM spectrum. Diagram from Schneider, Remote Sensing and the Global Environment, /
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  • Appearances May Deceive Optical properties vary at the nanoscale. Image source: L. R. Hirsch, R. J.Stafford, J. A. Bankson, S. R. Sershen, B. Rivera, R. E. Price, J. D. Hazle, N. J. Halas, & J. L. West, Proc. Natl. Acad. Sci. USA, 100, 13549- 13554 (2003). Proc. Natl. Acad. Sci. USA
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  • Blocking Out Signals Faraday Cage
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  • How does it work?
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  • Blocking Signals Activities Materials Needed Cell phone or small radio Small box with lid Aluminum foil Aluminum screen Scissors Tape and/or stapler ruler
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  • Activity Control Experiment 1. Turn on radio and set in box. 2. Place lid on box. 3. Turn off radio. 4. One (or more) group test with cell phone if available.
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  • Activity Box the Signal Wrap box and lid separately in aluminum foil (ensure snug fit). Set radio in box. Open box slightly (experiment with opening size). One (or more) group test with cell phone if available.
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  • Activity Screen the Signal Make a cylinder with aluminum screen. Leave one end open. Make a prediction. Place radio inside. Close other end of cage. Test with a cell phone if available.
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  • Wavelength and Frequency Activity Wavelength c/f C = 3.0 x 10 8 m/s Example 300,000,000m/s) / (540,000 Hz) = 55.6 m Frequencies AM radio: 540-1640 KHz FM radio: 88-174 MHz Cell: 850-1900 MHz
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  • What Size Mesh Do You Need? Mesh size 1/10 the wavelength
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  • Activity: Building a Faraday Cage Remove foil from top of box lid. Cut several strips of foil. Make a grid of strips on the lid. Experiment with size openings until a phone will not ring in box.
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  • Data Analysis and Conclusions When using aluminum strips, what size openings worked to stop the radio? A cell phone? Why does the opening size matter in a Faraday Cage? What other materials could be used?
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  • Wavelength Matters Locations where wireless equipment does not work Protection from electronic spies Space weather effects EMP
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  • Thank You!