Optics
Materials:
- Saucer
Saucer with figure
- Box
Box
- Color Cards
Remake color cards, push pins (pen or pencil)
- Size Cards
Remake size cards
- Fiber Optics?
Laser pointer, Fiber optics strands, Fiber optic shapes
Directions:
- Saucer
Use Harry Plopper (song)? Get a volunteer to point at HP with the laser pointer. What happens? Open up saucer. It’s a mirage.
- Box
Show students box. Put some change in the box. How can I do that? Open up box.
- Color Cards (Benham’s Disk)
Spin the cards. What happens? You can see colors.
- Size Cards
There is four possible ways to set these up:
Which one is bigger?
Background
- Saucer
Paraboloid mirrors create a mirage or a hologram.
- Box
There is a mirror placed at an angle which makes the box look like its floating.
- Color Cards
Benham's top
From Wikipedia, the free encyclopedia
A sample of a Benham's disk
Benham's top, also called Benham's disk, is named after the English toymaker Charles Benham, who, in 1895, sold a top painted with the pattern shown at right. When the disk is spun, arcs of pale color — called Fechner colors or pattern induced flicker colors (PIFCs) — are visible at different places on the disk. Not everyone sees the same colors.The phenomenon is not entirely understood. One possible reason people see colors may be that the color receptors in the human eye respond at different rates to red, green, and blue. Or, more specifically, that the latencies of the centre and the surrounding mechanisms differ for the different types of color-specific ganglion cells.The phenomenon originates from neural activity in the retina and spatial interactions in the primary visual cortex, which processes pattern recognition.[1] Research indicates that the blue-yellow opponent process accounts for all the different PIFCs.[2]Benham's top and other PIFCs are being researched for use as a diagnostic tool for diseases of the eye and the visual track. It has shown particular promise in detecting Optic neuritis.[3]
Cone cell
From Wikipedia, the free encyclopedia
(Redirected from Color receptors)
Normalized responsivity spectra of human cone cells, S, M, and L types
Cone cells, or cones, are photoreceptor cells in the retina of the eye which function best in relatively bright light. The cone cells gradually become more sparse towards the periphery of the retina.
A commonly cited figure of six million in the human eye was found by Osterberg[1] in 1935. Oyster's textbook (1999) cites work by Curcio et al. (1990) indicating an average closer to 4.5 million cone cells and 90 million rod cells in the human retina.[citation needed]
Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of color. They are also able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods.[2] Because humans usually have three kinds of cones, with different photopsins, which have different response curves, and thus respond to variation in color in different ways, they have trichromatic vision. Being color blind can change this, and there have been reports of people with four or more types of cones, giving them tetrachromatic vision.
- Size Cards
Depending on how you turn them the different colored arcs appear to be different sizes even though they actually are the same size.
- Fiber Optics
Used in electronics instead of wires. Telecommunication… Total internal reflection…
Liquid Nitrogen
Materials:
Liquid Nitrogen, Gloves, Large Styrofoam container, Styrofoam cup, Tupperware Bin, Tablecloth, Caution tape
- Rose
Rose, Styrofoam cup half full of LN2, Gloves
- Cork pop
Cork and tube, Small cup with one dram LN2, Gloves
- Balloon
Balloon, Test tube, Small cup with one dram LN2, Gloves
- Hot water and bubbles?
Hot water, Dishwasher detergent, Food coloring, Large Styrofoam container, Gloves, Styrofoam cup full of LN2
- Graham Crackers
Graham crackers, Styrofoam cup, Tongs, Gloves
Directions:
- Rose
Use the gloves. Place the rose in a half full Styrofoam cup of LN2. Remove after ~10 seconds and crush in a gloved hand.
- Cork pop
Use the gloves. Pour about one dram worth of LN2 in the small cup from the Styrofoam cup. Pour from the Styrofoam cup into the tube. Quickly and smoothly cork the tube. The cork pops within one second. The more seamless the corking the more times the cork can be popped.
- Balloon
Blow the balloon up and place it on the test tube. Place the balloon and test tube combo in the large Styrofoam container. Pour the half full Styrofoam cup of LN2 over the combo, wait for the balloon to shrink. Pull out the combo and watch the balloon expand again.
- Hot water and bubbles
Fill the large Styrofoam container half full with hot water. Put a couple of tsp of dishwashing detergent in the container, you could also add food coloring. Use the gloves and add a Styrofoam cup full of LN2.
- Graham crackers
Using tongs and gloves place a piece of graham cracker in LN2 for about 10 seconds. Pull out and wave around vigorously for 10 seconds. Get a student to voluntarily eat a cracker and watch him/her steam away!
Background:
Cold – What’s the temperature outside (22-40 F)? How about room temperature (70 F)? Wyoming’s record low is -66F! Where (Yellowstone)? Earth’s record low is -129F! Where (Antarctica)? LN2 has a really low boiling point, in order to get LN2 to be liquid it needs to be at 77K (that’s about -321 F!).
Phase – What is this LN2 doing (boiling)? What is water’s boiling point (212 F)? What does boiling mean (changing liquid to gas)? What takes up more room liquid or gas (gas)? When LN2 phase changes to gas it expands to about 2000 times its liquid volume.
LN2 Cautions – Non-toxic, Non-combustible, BUT liquid to gas expansion factor of 2000 therefore airtight seals are hazardous, and extremely cold therefore prolonged exposure results in frostbite! We use LN2 to cool down electronics (work better when they are cold). Atomic number = 7, atomic mass = 14.007, 78% of earth’s atmosphere.
We (astrophysicists) use LN2 to cool down electronics (CCD camera, work more efficiently when they are cold, reduce the number of false e- signaling from random thermal bumping).
- in the study of cryogenics
- as a source of very dry nitrogen gas
- the immersion freezing and transportation of food products
- the cryopreservation of blood, reproductive cells (sperm and egg), and other biological samples and materials
- as a cooling supplement for overclocking a central processing unit, a graphics processing unit, or another type of computer hardware[3]
- as a method of freezing water pipes in order to work on them in situations where a tap is not available to block water flow to the work area.
- in cryotherapy for removing unsightly or potentially malignant skin lesions such as warts and actinic keratosis.
- in the process of promession, a way to dispose of the dead.
- cooling a high-temperature superconductor to a temperature sufficient to achieve superconductivity.
- the cryonic preservation of humans and pets in the hope of future reanimation.