ChatterBank2 mins ago
spoons!!
7 Answers
my 4yr old daughter asked me yesterday why we appear upside down in spoons?
i didnt know the answer?? please tell me!
i didnt know the answer?? please tell me!
Answers
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Been trying to find somewhere that explains it in simple language, as it's basic physics and to do with the spoon becoming a concave mirror.
But then I re-read your question, and given that your daughter is 4, the correct answer is that it's magic, and caused when the fairy godmother put a spell on spoons to let children see what they look like when they stand on their heads!
Been trying to find somewhere that explains it in simple language, as it's basic physics and to do with the spoon becoming a concave mirror.
But then I re-read your question, and given that your daughter is 4, the correct answer is that it's magic, and caused when the fairy godmother put a spell on spoons to let children see what they look like when they stand on their heads!
If you should choose not to take the easy way out and have the patience to learn as well as teach, I offer the following information that I hope will help you in preparing an explanation your daughter will appreciate.
It might be helpful to first explain how a regular flat mirror works:
Light tends to travel in straight lines (rays) unless refracted or reflected.
Refraction occurs when light rays encounter a translucent medium of a different density at an angle. The apparent abrupt dislocation of a spoons handle in a glass of water (viewed from the side) illustrates this principle.
Reflection occurs when light encounters a surface that does not absorb it or allow it to pass through. Reflected light bounces back at an angle equal to the angle of incidence. Rolling a rubber ball at various angles towards a flat surface such as a wall illustrates this principle.
A mirror is a flat smooth surface that reflects the light rays from an image at the same angle thereby maintaining the arrangement of the light rays proceeding from the original image.
A smooth reflective curved surface will maintain the order of the image it reflects but will progressively alter the direction of reflection of the original image as we move across the constantly and consistently changing angle of its surface. If the surface is convex (curving outward like the bottom of the spoon) the various rays of light reflecting across it surface will diverge as though radiating from a point behind the curvature of the reflective surface. This produces an image reduced in apparent size while reflecting a broad panorama of view toward the eye.
cont.
It might be helpful to first explain how a regular flat mirror works:
Light tends to travel in straight lines (rays) unless refracted or reflected.
Refraction occurs when light rays encounter a translucent medium of a different density at an angle. The apparent abrupt dislocation of a spoons handle in a glass of water (viewed from the side) illustrates this principle.
Reflection occurs when light encounters a surface that does not absorb it or allow it to pass through. Reflected light bounces back at an angle equal to the angle of incidence. Rolling a rubber ball at various angles towards a flat surface such as a wall illustrates this principle.
A mirror is a flat smooth surface that reflects the light rays from an image at the same angle thereby maintaining the arrangement of the light rays proceeding from the original image.
A smooth reflective curved surface will maintain the order of the image it reflects but will progressively alter the direction of reflection of the original image as we move across the constantly and consistently changing angle of its surface. If the surface is convex (curving outward like the bottom of the spoon) the various rays of light reflecting across it surface will diverge as though radiating from a point behind the curvature of the reflective surface. This produces an image reduced in apparent size while reflecting a broad panorama of view toward the eye.
cont.
In the case of the concave surface inside the spoon the rays reflected converge at a point a small distance from the curved surface. Beyond the point at which the converging lines of the reflected image cross the image will be inverted top to bottom and left to right. What is happening to the image closer to the spoon where the rays converge (the focal point) can be observed by reducing the distance between the spoon and eye until the size of the reflected image approaches infinity. A concave (magnifying) mirror will better illustrate this phenomenon.
If you have a concave mirror you might also try projecting and focusing the reflected image from a window to an adjacent wall or a piece of white poster board. See if you can deduce the path of the light rays to the image as they are reflected from the actual scene. An otherwise dark room works best.
DO NOT LOOK INTO ANY MAGNIFIER WHERE DIRECT SUNLIGHT MAY BE OBSERVED!
I�ll now leave it to you to relay this information to your daughter with the advise that knowledge is conveyed by relating it in terms that can be understood based on mutually shared observations and experiences. That she was able to express the question so coherently presents a challenge to answer it in a way that is equally coherent. This will leave a lasting image in her mind that reflects your concern for her intellectual development and well being. Good luck! If I were to wager on the outcome of all of this I would bet that you end up learning more from her than you did from me.
applet demonstrating convergence and subsequent inversion of light rays in a concave mirror
Grab and reposition the point on the red line.
If you have a concave mirror you might also try projecting and focusing the reflected image from a window to an adjacent wall or a piece of white poster board. See if you can deduce the path of the light rays to the image as they are reflected from the actual scene. An otherwise dark room works best.
DO NOT LOOK INTO ANY MAGNIFIER WHERE DIRECT SUNLIGHT MAY BE OBSERVED!
I�ll now leave it to you to relay this information to your daughter with the advise that knowledge is conveyed by relating it in terms that can be understood based on mutually shared observations and experiences. That she was able to express the question so coherently presents a challenge to answer it in a way that is equally coherent. This will leave a lasting image in her mind that reflects your concern for her intellectual development and well being. Good luck! If I were to wager on the outcome of all of this I would bet that you end up learning more from her than you did from me.
applet demonstrating convergence and subsequent inversion of light rays in a concave mirror
Grab and reposition the point on the red line.
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