Constructing Ideas in Physical Science Joan Abdallah, AAAS Darcy Hampton, DCPS Davina Pruitt-Mentle, University of Maryland CIPS Institute for Middle School Science Teachers

AAAS/DCPS CIPS Workshop8/2-8/13 2 Session 6 Debriefing What do you remember from yesterday’s session (no peeking at text or notes) What were the “essential questions” being asked/explored What conclusions did “we” decide

AAAS/DCPS CIPS Workshop8/2-8/13 3 Deeper Questions What deeper questions could you envision students asking? What misconceptions or misinterpretations can you foresee? How or what would you say?

AAAS/DCPS CIPS Workshop8/2-8/13 4 Deeper Questions or Possible Misinterpretations “How come light only bounces off mirrors?” What would you say?

AAAS/DCPS CIPS Workshop8/2-8/13 5 Target Ideas A light interaction occurs when a source of light illuminates a nearby object During a light interaction, light energy is transferred from the source to the receiver Light travels in straight-lines To see an object, light from that object must enter the eye. Visual energy is a form of energy associated with seeing things A shiny object reflects light in a particular direction A clear object reflects light in a particular direction and transmits light A white, non-shiny object reflects light in all directions away from its surface

AAAS/DCPS CIPS Workshop8/2-8/13 6 Why Do We “See” After We Close Our Eyes? You see because light enters your eyes and produces chemical changes in the retina, the light-sensitive lining at the back of your eyes. Prolonged stimulation by a bright image (here, the light source) desensitizes part of the retina. You continue to see the image for a short time after the stimulus goes away. This is called an “afterimage” Source: Also see:

AAAS/DCPS CIPS Workshop8/2-8/13 7 Why is the Sky Blue The physical phenomenon called Rayleigh scattering causes light to scatter when it passes through particles that have a diameter one-tenth that of the wavelength (color) of the light. Sunlight is made up of all different colors of light, but because of the elements in the atmosphere (mainly nitrogen and oxygen) the color blue is scattered much more efficiently than the other colors. So when you look at the sky on a clear day, you can see the sun as a bright disk. The blueness you see everywhere else is all of the atoms in the atmosphere scattering blue light toward you. (Because red light, yellow light, green light and the other colors aren't scattered nearly as well, you see the sky as blue.) Source: [Local] See also: Note: the Tyndall Effect and Rayleigh Scattering are the same thing

AAAS/DCPS CIPS Workshop8/2-8/13 8 Convex vs. Concave Mirrors A Concave mirror bends away from the viewer –Like the inside of a spoon –Tends to make things look bigger (closer) –Smaller field of view A Convex mirror bends toward the viewer –Right side view mirror –Tends to make things look smaller (further away) –Larger field of view Sources and for more detail Excellent – must see – All mirror info [Local Copy]Local Copy

AAAS/DCPS CIPS Workshop8/2-8/13 9 Eye Sight Nearsightedness (myopia) –In nearsightedness (myopia), the light from distant objects gets focused in front of the retina rather than on it. –Myopia can be corrected by using a concave lens to diverge, or spread out, the light so that when it passes through the lens system, it comes to focus on the retina. Source: [Local] More at: [Local] From Thinkquest -

AAAS/DCPS CIPS Workshop8/2-8/13 10 Eye Sight Farsightedness (hyperopia) –In farsightedness (hyperopia), the light gets focused in back of the retina rather than on it. –Hyperopia can by corrected by using a convex lens to concentrate or converge the light so that when it passes through the lens system, it comes to focus on the retina. Source: [Local]

AAAS/DCPS CIPS Workshop8/2-8/13 11 Project 2061 Benchmarks and Target Ideas