Wednesday, August 15, 2012

My Shadow

My Shadow
I have a little shadow that goes in and out with me,
and what can be the use of him is more than I can see.
He is very, very like me from the heels up to the head;
and I see him jump before me, when I jump into my bed.

The funniest thing about him is the way he likes to grow-
not at all like proper children, which is always very slow;
For he sometimes shoots up taller like an india-rubber ball,
and he sometimes gets so little that there's none of him at all.

He hasn't got a notion of how children ought to play,
and can only make a fool of me in every sort of way.
He stays so close beside me, he's a coward you can see;
I'd think shame to stick to nursie as that shadow sticks to me.

One morning, very early, before the sun was up,
I rose and found the shining dew on every buttercup;
But my lazy little shadow, like an arrant sleepy-head,
Had stayed at home behind me and was fast asleep in bed.

-Robert Louis Stevenson

During a sunny saturday prepare to take your child outside a couple of times with a tape measure and sidewalk chalk.  Sometime in the morning when the sun is still low have your child stand still as a statue and trace his/her feet tightly and then the perimeter of his/her shadow.  Your child can do the same for you.  Go back out at noon and in a spot near to the first set of chalk-marks, do the same thing again.  Repeat this again at about 3:00 and then again in the evening not long before bed (or sunset whichever is most appropriate)

Things to do with the information - same night or next day:

Measure the lengths of the shadows together and record them in a notebook.  

Create a graph showing the lengths of the shadows on the y axis and the time of day on the x axis.

Discuss the angle of the sun as a possible cause for the changes in your shadows and then test the hypothesis in a dark room using a flashlight and something tall (a shampoo bottle, opaque glass . . .) see if the effect can be recreated.

Bonus Activity:  After it is evident your child understands that a shadow changes depending on the angle of the light hitting it, you might try learning about, and then making your own sundial.

For information regarding how they work and the history of sundials try:

Long Stick/Stake
Mallet, hammer or other item (large rock) to pound it into the ground.
Sunny Day

Use a long stake and drive it into the ground so that it points at the sun. (in other words, unless it is noon it should not be straight up and down).   The stick should not make much of a shadow right away.  Wait about an hour until a distinct shadow has appeared that is about 6 inches long.  Mark this point according to what time it is and then continue to mark the shadow every hour.  This sundial will now work approximately for a few days.  However, the angle of the sun varies over the course of the year so it will not remain accurate perpetually.  To make a more permanent sundial is much more complex.  If you have an interested kid and would like to try it though, here is a website that lays out the details for building a portable sundial.  This is a teacher to students about sundial making as an assignment.

Definitely for your highschooler.

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