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Bill shows how the three key characteristics of laser light – single wavelength, narrow beam, and high intensity – are made. He explains the operation of a ruby laser – the first laser ever made – showing how electronic transitions create stimulated emission to give coherent light, and then how the ends of the ruby cavity create a narrow wavelength highly collimated beam. You can learn more about laser in the EngineerGuy team’s new book Eight Amazing Engineering Stories http://www.engineerguy.com/elements
For the majority of recorded human history, units like the weight of a grain or the length of a hand weren’t exact and varied from place to place. Now, consistent measurements are such an integral part of our daily lives that it’s hard to appreciate what a major accomplishment for humanity they’ve been. Matt Anticole traces the wild history of the metric system.
Lesson by Matt Anticole, animation by Globizco.
3-D weaving growing new hip; thumb sucking not all bad; teens’ brains and hormones; new source of helium; internet-beaming solar drone; science-savvy songs; Viking 1 40 years old; possible habitability on two exoplanets – just a few of the themes in today’s eclectic collection of SciNews. Share these stories with your students and get them excited about science.
Only 4 countries at risk for spreading Zika virus; opposite responses between genders after MRI; chemical signals in the air at the movies; electricity generated through osmosis; Canadian military using Canadian bionic knee brace; solar plane lands in Egypt; swordfish grease heads; first pictures of Jupiter from Juno – just a few of the themes in today’s eclectic collection of SciNews. Share these stories with your students and get them excited about science.
««« Written by Chuck Hammill via the STAO/APSO Elementary Curriculum Committee. This activity is recommended for use with the Ontario Curriculum, Grade 1: Understanding Structures and Mechanisms
It’s in our tap water, toothpaste and even in tea. Fluoride has helped reduce cavities in children for decades. Still, more than 70 years after Grand Rapids, Michigan, became the first city to fluoridate its drinking water, the practice remains controversial. Some worry that fluoridated drinking water can lead to health issues, but what is the scientific consensus?