Upcoming Deadlines

1. Pick up a clicker, find the right channel, and enter Student ID Upcoming Deadlines Second Term Paper – Science Fact or Cinematic Fiction? Due Wednesday, April 21st (This Wednesday!) 100 points (50 points if late) Homework #11 – Building a Scene in Maya Due Wednesday, April 28th (Next week) 20 points (10 points if late) There are no more furlough days for this class this semester. For full schedule, visit course website: ArtPhysics123.pbworks.com

2. Second Term Paper Your second term paper, “Science Fact or Cinematic Fiction”, due Wednesday. Length (1500 words), structure, grading rubric, etc. similar to the first term paper. Due by 8am on Wednesday, April 21st . 100 points (if late, 50 points)

3. Final Exam Final Exam will have of 10 short essay questions on material covered in lecture. Final exam counts for 50 points. See website for sample exam from last semester. Final exam is scheduled will be on Wednesday, May 19th in this room from 1215—1430.

4. Wanted: 3D Glasses If you have any extra 3D glasses you’re willing to donate, please bring them in. Both anaglyph (red/blue) and polarized (Real3D) are needed.

5. Guest Lecture Prof. Raquel Coelho will give a special lecture on lighting in computer generated images. In class, Wed., April 28th Coelho has worked for studios such as Blue Sky and PDI/Dreamworks, Wildbrain Inc and Tippett Studio, as animator in films such as "Charlotte's Web", "Hellboy", "The Spiderwick Chronicles" and "Happy Feet".

6. Acoustic Resonance If amplitude of the sound is sufficiently large, resonant vibrations can shatter a wine glass. http://www.youtube.com/watch?v=BE827gwnnk4

7. Activating your Clicker * Turn on your clicker. * Enter the channel number or letter for joining this class. Hit Enter/Send key. * Clicker should read AP123S258 * Type in your student ID; hit Enter/Send. Clicker is now ready to use; leave it on. Hit any key to wake the clicker from sleep mode.

8. Survey Question How many do you like using the blog for submitting your term paper: • Like it a lot • Like it • Neutral • Don’t like it • Don’t like it a lot

9. Review Question • Sparks from sparkler don’t burn skin because: • The sparks are bright but don’t have a high temperature. • The sparks are high temperature but they don’t have much internal energy. • The sparks have a very low conductivity.

10. Review Question B) The sparks are high temperature but they don’t have much internal energy. . . . . . . . . The sparkler sparks have high temperature (5000 ºF) and high conductivity (burning iron) but are very small, with little mass. By analogy, grains of sand that fall from a great height doesn’t have as much energy as a cannonball that falls a couple of feet. x x

11. Effects Animation:Hot & Cold (cont.)

12. Heating & Cooling Increase temperature by adding internal energy (heat flows into object) Energy Decrease temperature by removing internal energy (heat flows out of object) Energy

13. Transfer of Thermal Energy • There are three primary mechanisms for the transfer of thermal energy: • Conduction – Direct contact of objects • Convection – Fluid motion carrying energy • Radiation – Light shining on an object • Let’s see examples of each mechanism.

14. Conduction Conduction is heat flow by direct contact. Some materials are good thermal conductors, others are insulators. Tile floor feels colder than wood floor 98º 98º 75º 75º Wood is an insulator Tile is a conductor

15. Air is a Poor Conductor Because air is such a poor conductor, some pizza ovens don’t have a door. Can safely put your hand in an hot oven. Metal is good conductor so you need oven mitt to touch it (cloth is poor conductor).

16. Convection Heat transfer in a fluid often occurs mostly by convection. Buoyancy causes warm air to rise, which carries thermal energy directly by its motion.

17. Demo: Candle Very HOT Rising hot air above a candle carries most of the heat generated by the burning flame. Warm Shadows reveal rising air currents of hot air.

18. Convection Oven Convection oven has a fan to enhance the circulation of the air, increasing the transfer of heat.

19. Demo: Candle in a Tube Candle stays light until the partition in the tube is removed. Why? Partition allows hot air to rise, drawing in cold air (with fresh oxygen) to fuel the candle flame. Without the partition, turbulence impedes the inflow and outflow. Convection is disrupted because tube is narrow.

20. Fiberglass Insulation Air is a poor thermal conductor but easily transfers heat by convection. Fiberglass insulation is mostly air, with the fibers disrupting the convection flow.

21. Radiation Light has many different wavelengths, most of which are not visible to the eye. All light carries energy, thus transfers heat. Heat Lamp Highly reflective fire proximity suits

22. Heat-Ray The “heat-ray” first appeared in science fiction as the Martian weapon in H.G. Wells’ classic novel, War of the Worlds (1898). Mars Attacks! (1997) War of the Worlds (1953) http://www.youtube.com/watch?v=gsXnK0ouTL8 High powered lasers are similar to H.G. Wells’ heat-ray.

23. Freeze-Ray There’s no current technology to create a ray that removes energy from an object. 1968 Batman cartoon Batman and Robin (1997) http://www.youtube.com/watch?v=TNjTW8ZBkuI

24. Emission of Radiant Energy 75º All objects radiate light; higher the temperature the higher the light’s frequency. At room temperature the radiated light is at frequencies too low for our eyes to see. Special cameras are sensitive to this infrared radiation. 98º Attics in this house were kept warm for growing marijuana.

25. Predator (1987) Heat vision made the Predator a deadly adversary.

26. Demo: Infrared Light Digital cameras, such as in cell phones, are sensitive to infrared light, such as from a remote control or any hot object. Microwave Receiver Microwave Transmitter

27. Effects Animation:Electricity & Magnetism

28. The Force Electrical and magnetic phenomena are the inspiration for many special effects, such as the mysterious “Force” in the Star Wars epics.

29. Electric Charges and Forces There are two types of charge: positive charges and negative charges REPEL REPEL ATTRACT Like charges repel, opposite charges attract.

30. Charging by Friction/Contact Electrons move easily so an object can become charged by rubbing electrons off the object’s surface. • Brush your hair with a plastic comb. • Walk across a carpet with plastic-soled shoes. Electrons taken off of fur onto rubber rod

31. Demo: Electroscope The “legs” of an electroscope separate when the electroscope is charged due to the repulsion of like charge on the two legs. Charged ebonite rod deposits negative charge (electrons) onto electroscope. “Legs”

32. Demo: Dial Electroscope Alternative design for electroscope Neutral Charged

33. Demo: Van de Graff Generator Van de Graff deposits large quantities of excess charge on its globe. A person with long hair can become a human electroscope. Repulsion also demonstrated with pie plates, Rice Krispies, etc.

34. Demo: Electric Pinwheel Pinwheel turns as charge leaves the Van de Graff from the points at the tips of the spokes. Charged Air molecules Van de Graff

35. Plastic Insulators Plastic insulation on step of van de Graff and charge wand keep charge from leaving the metal balls. Plastic insulation on wire prevents charge to leave wire except at the ends, where the conducting metal is exposed.

36. Demo: Tesla Coil Air is an insulator but at high voltages it can conduct electricity as lightning. Portable Tesla coil

37. Tesla Coils Very high voltages achieved with large Tesla coils. Homemade, backyard model Fry’s Superstore, Fremont CA

38. Faraday Cage http://www.youtube.com/watch?v=Zi4kXgDBFhw

39. Ohmic Heating Flowing electrons strike atoms in a conductor, heating the material. Hellboy (2004) Toaster http://www.youtube.com/watch?v=OGezvYafezE

40. Next LectureMore Electricity + Magnetism Second Term Paper due this Wednesday! Please turn off and return the clickers!