GREAT
EXPLORATIONS - Moving air | Forming
images | Reflecting light | Electricity
and magnetism | Spinning things | Making
sense | Changing colours | Making
sounds and waves | Moving to and fro
| Thinking about shapes
This is an old set of proven ideas, for reference. My latest designs are
far better!
Changing
colours
Polaroid
colours
TEXT:
Look at the screen though one of
the pieces of polarising plastic.
Keep looking while you slowly turn the plastic
filter.
You are looking at ordinary sellotape with a
large polarising filter behind. Polaroid sunglasses can give the same
effect.
This is a beautiful, 'direct' experience, so it hardly matters that any
meaningful explanation is well beyond the scope of a brief label. (The
sellotape is 'optically active' and rotates the plane of polarisation
of different wavelengths of light by different amounts depending on the
thickness of tape through which it passes.)
Secret
messages
(Sorry, no picture.)
TEXT:
Look at the "messages"
through the pieces of coloured plastic.
Which writing seems to disappear when you
look through the red plastic? Which disappears when you look through the
green plastic?
Does looking through each piece of coloured
plastic make other, different, colours appear darker or lighter?
The meanings of the messages and the simple pictures change when looked
at through the coloured plastic.
Turning
prism
TEXT:
Turn the glass prism and watch
the rainbow colours on the screen.
Can you see the beam of light being "bent"
as it shines through the prism?
Which colour is "bent" most, red or
blue? Are you sure you can see seven different colours, or are you "seeing"
what you have been taught to see? Do you think indigo really deserves
to be given a separate name?
The spectrum appears on a translucent acrylic screen, making it visible
from both sides. Other rays also appear which are conveniently ignored
by textbooks! It is interesting to watch the way the rays move when you
turn the isosceles prism. Most, if not all, people, if they are honest,
are completely unable to see indigo as a separate colour.
Secondary
colours
TEXT:
How many different colours can
you see here?
What happens when two of the coloured discs
overlap? What happens when all three discs overlap?
With these three colours in your paintbox, you
can mix them to make any other colour.
The cyan and yellow discs are hanging from cords in front of the illuminated
lightbox. The magenta disc is fixed to the screen below them
Colour
cube
(Sorry, no picture.)
TEXT:
How many different colours can
you see when you walk round the glass cube?
How many sides are you looking through to
see each colour?
Can you work out the real colour of each side?
One of them is clear glass: which one? How do the colours of your friends'
clothes appear through the cube?
Whichever way you look at it, you always have to look through two different-coloured
windows at a time. This makes it a real puzzle to figure out the real
colour of each window.
Ultraviolet
light
TEXT:
Look at the objects inside this
box.
The ultraviolet light is making them glow.
Ultraviolet light makes some things glow but
not others. Are you carrying anything fluorescent that you could try?
E.g. some white paper, material washed in 'whiter than white' soap powders,
some 'dayglo' hair bands etc., or even dandruff on your sleeve!
The enclosure contains two fluorescent UV tubes protected by wire mesh.
The inside is black and many of the objects are hanging from cords. You
can reach inside through two tall, narrow openings.
GREAT
EXPLORATIONS - Moving air | Forming
images | Reflecting light | Electricity
and magnetism | Spinning things | Making
sense | Changing colours | Making
sounds and waves | Moving to and fro
| Thinking about shapes
This is an old set of proven ideas, for reference. My latest designs are
far better!
|
