logging in or signing up microwave ovens Elodie Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Copy Does not support media & animations WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 5223 Category: Entertainment License: All Rights Reserved Like it (4) Dislike it (0) Added: November 06, 2007 This Presentation is Public Favorites: 4 Presentation Description No description available. Comments Posting comment... By: aaadel (31 month(s) ago) can I dawnload it ? Saving..... Post Reply Close Saving..... Edit Comment Close By: aaadel (31 month(s) ago) thx Saving..... Post Reply Close Saving..... Edit Comment Close By: vishwa_a4 (45 month(s) ago) avg Saving..... Post Reply Close Saving..... Edit Comment Close By: tamermania (49 month(s) ago) thank you for your presentation and i admire of it please i want to download it but i can't please give me premission to download it i need in important coursr to me Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Microwave Ovens: Microwave Ovens Question:: Question: If you put a CD in a microwave oven, it will do nothing. burn up the microwave oven. burn up the CD.Observations About Microwaves: Observations About Microwaves Microwave ovens cook food from inside out They can cook foods unevenly They don’t defrost foods well You shouldn’t put metal inside them?! Do they make food radioactive or toxic?Electromagnetic Spectrum: Electromagnetic Spectrum Long-wavelength EM waves: Radio & Microwave Medium-wavelength: IR, Visible, UV light Short-wavelength: X-rays & Gamma-raysWater Molecules: Water Molecules Water molecules are unusually polar An electric field orients water molecules A fluctuating electric field causes water molecules to fluctuate in orientationMicrowave Heating: Microwave Heating Microwaves have fluctuating electric fields Water molecules orient back and forth Liquid water heats due to molecular “friction” Ice doesn’t heat due to orientational stiffness Steam doesn’t heat due to lack of “friction” Food’s liquid water content heats the foodEffects of Microwaves: Effects of Microwaves Non-Conductors: Polarization Mobile, polar molecules orient and heat Immobile, polar molecules do nothing much Non-polar molecules do nothing much Conductors: Current flow Good, thick conductors reflect microwaves Poor conductors experience resistive heating Thin conductors experience resistive heatingQuestion:: Question: If you put a CD in a microwave oven, it will do nothing. burn up the microwave oven. burn up the CD.Interference: Interference Identical waves that overlap can interfere Interference is when the fields add or cancel Adding fields are constructive interference Canceling fields are destructive interference Reflects cause interference in a microwave Interference causes uneven cooking Good microwaves “stir” waves or move foodGenerating Microwaves: Generating Microwaves Magnetron tube has tank circuits in it Streams of electrons amplify tank oscillations A loop of wire extracts energy from tanks A short ¼-wave antenna emits the microwaves You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.