Physics experiment for the day from Camille.
Equipment: ordinary (somewhat shiny) kitchen spoon
Procedure:
1. Look at your image in the "bowl" of the spoon. Record what you see.
2. Turn the spoon over and look at your image on the "back" or bottom of the spoon. Record what you see.
3. Discuss!
Of course! you say. Now you remember basic ray optics* from high school physics, or, these days, you'd probably get it in third grade.
You may also remember that the "upside down" image is called "real," meaning that it can be captured on a screen or a piece of paper, for example; and the "right side up" image is called "virtual," meaning it can be seen with our eyes, but can't be picked up on anything tangible.
I've always taken comfort in the fact that when my world looks upside down, it's real. Everything else is virtual.
*Here's a YouTube refresher – very clearly narrated ray diagramming for a concave mirror.
Camille, I'm sitting here with my about-to-start-third grader, who said, when I read it, "Oh, I already knew about that." I'm not sure either he or I REALLY knows the why of it - thanks for getting us started on the topic.
Posted by: Susan Shea | August 22, 2012 at 01:05 PM
Fun! See if he likes the video - it shows how the image is formed by tracing the rays.
Posted by: Camille Minichino | August 22, 2012 at 01:23 PM
I remember when I showed my kids this "spoon trick" way back when. They were fascinated! I didn't get into a "real/virtual" discussion with them about it, though... :-)
Posted by: Ann | August 22, 2012 at 07:27 PM
Good training, Ann! No wonder they're both so smart!
Posted by: Camille Minichino | August 22, 2012 at 09:01 PM
I guess they need to change the title of that show from Are You Smarter Than a Fifth Grader to a Third Grader.
Posted by: Michael A. Black | August 25, 2012 at 10:46 AM
The truth, Michael!
Posted by: Camille Minichino | August 25, 2012 at 03:45 PM
Wow...I balance a spoon on my nose, but never looked at my reflection. You can't capture the right side up version? How can I be this old and not know that?
Posted by: Mysti | August 25, 2012 at 07:41 PM
You might remember an optical bench, Mysti, where you use a meter stick as a "bench" and move lenses and "objects" (usually a piece of cardstock with an arrow drawn on it), and a screen (another piece of cardstock), and light source, back and forth and look at the image. If you can pick up an image at any point on the bench, on the card, it's "real."
Here's a link to a drawing of a set up: http://www.scientificsonline.com/economy-optical-bench.html
Posted by: Camille Minichino | August 25, 2012 at 09:09 PM
oops, I think the link is to a kit that you can by, not a drawing.
Posted by: Camille Minichino | August 25, 2012 at 09:10 PM
Sneaky pete. you get math and physics in every chance you get.
wish I'd had you for my math teacher. maybe I wouldn't have failed.
Posted by: rita lakin | August 28, 2012 at 09:14 AM
Hey, Rita, you noticed the physics huh?
Posted by: Camille Minichino | August 28, 2012 at 09:40 AM