Q & A Walk

1. DO NOW: EM journals in In Box. Then…Using appropriate vocab terms, please explain exactly what is going on in this photo. Does light change media? Speed up? slow down? Bend? Refract? BE COMPLETE!

2. Q & A Walk • Participate in the Walk or 5k and get +3 on your final exam • Bring me your race bib next week and/or registration bag to claim your points. • For info email: rua@robbinsville.k12.nj.us • Entry fee: $20 before June 8 ($18 for USATF Members and students 14 and under), $25 on race day, $18 fitness walk • Give Ms. Rua your registration form and fee. • Make Checks Payable to: Robbinsville High School • Information on the RHS website

3. Speed of light… • Is ‘c’ in a vacuum • Is slower in air • Slower still in water • And even slower in glass • Looking at this picture, you have A LOT of changing media, and therefore changing speeds. • As light slows down, it ‘bends’ (refraction)

5. Light from is refracted through the sides of the thick glass - making the glass appear thinner than it is. The eye is used to seeing in straight lines, and perceives the root beer to be at the outer edge of the glass

6. That frosty mug full of A&W root beer seems to drain so quickly. What seems like a lot of root beer is actually a lot of glass. The deception is uncovered when the root beer mug is submerged in water. When looking at the mug above the water level, there appears to be a lot of root beer. But when looking at the mug below the water level, one observes the truth; the water surrounding the glass minimizes the effect of refraction and reveals the large quantity of glass. We've been deceived!  • That frosty mug full of A&W root beer seems to empty so quickly. What seems like a lot of root beer is actually a lot of glass. The deception is uncovered when the root beer mug is submerged in water. When looking at the mug above the water level, there appears to be a lot of root beer. But when looking at the mug below the water level, one observes the truth; the water surrounding the glass minimizes the effect of refraction and reveals the large quantity of glass. We've been deceived! • Can you think of other products that may use this ‘physics’ illusion to make you think you are getting more product than you actually are?

8. (light slows down at water – it ‘bends’ and the image appears to be closer… this explains quarter, too!) • Make correction/ additions • changes… questions? • From yesterday’s exit:

9. To explain prism, you must understand that high frequency light (violet) travels more slowly through glass than low frequency light (red)

10. Today’s Demos • Same as last class:

11. Luminous vs. Illuminated • What’s the difference? DISCUSS • Conclusions? • Luminous: emits its own light, light source, shines, etc. • Examples? • Illuminated: lit up because other light is shining on it, does not emit its own light, does not shine on its own, etc. • Examples?

12. So…is Rihanna a physics genius? • Does ‘shine bright like a diamond’ make ‘physics’ sense? DISCUSS • Thoughts?

14. So why are diamonds so sparkly?

15. (Or any reflective surface!)

16. Critical angle -  the angle of incidence above which total internal reflection occurs (in other words, at an angle LARGER THAN the critical angle, you observe total internal reflection – TIR) • TIRonly takes place when both of the following two conditions are met: • a light ray is in the more dense medium and approaching the less dense medium. • the angle of incidence for the light ray is greater than the critical angle(as mentioned above)

17. You can observe total internal reflection when swimming: • Or with ‘fiber optics’

18. You can observe total internal reflection when swimming: • Or with ‘fiber optics’ • Or with diamonds

21. Goals • See teacher to check in on any previous POGILS (they should be done and checked by the end of class) • Finish your FINAL POGIL of the school year! • Prep for your quest next class! • Fill out exit slip and turn in NEXT CLASS – You will take your quest NEXT WEEK – you will get your quest back and have all of next week’s physics classes to prep for finals (study, work on cheat sheet, complete study guide  this will be posted on my website this week for you to print)