Chapter 18: Home Demos
1. Look at your own image in a bathroom mirror and notice
how it moves toward the mirror when you move toward the mirror
and how it moves away from the mirror as you move away from the
2. Ask a friend to use masking tape on a full-length mirror
to carefully mark the location of the top of your head and the
bottom of your feet as you look at your image in the mirror. How
does the distance between these marks compare to you own height?
Try this for several different locations-that is, stand at several
different distances from the mirror.
3. Look at yourself or something else in the back of a
shiny spoon. What kinds of images can you form?
4. Look at yourself or something else in the inside of
a shiny spoon. What kinds of images can you form?
5. Try the situation of Figure 18.12 for yourself. Put
a coin in the bottom of a bowl and position yourself so the side
of the bowl hides the coin and you can not see the coin. Then
have a friend pour water into the bowl. You should now be able
to see the coin, as if it had been lifted part way up from the
bottom of the bowl.
6. Put two mirrors together in a corner, at 90 to each
other. Look at yourself in these mirrors. Wave at yourself and
notice which hand waves back!
7. Build a periscope using two mirrors and a long cardboard
box or a cardborad mailing tube. A periscope is great for seeing
above a crowd as well as looking around a corner.
Figure 18.I Build a periscope using two mirrors.
8. Use a converging lens (or a concave mirror) to focus
the Sun's rays onto a piece of paper and catch it on fire. It
may help to focus on a dark area of the paper, such as an ink
spot or a penciled-in area.
9. Use a converging lens-such as a magnifying glass-to
project an image onto a piece of paper. Is this a real or virtual
image? Project an image of a nearby light bulb. Project an image
of a far-distant tree or something else you see through your window.
10. Hold a candle in front of a concave mirror-like a shaving
mirror or a make-up mirror-and move it back and forth until you
see its image, which will be upside down, at the same position
as the object (the candle). Adjust its position until you see
the candle burning at both ends.