NCERT Book Class 6 Science Chapter 8 Light, Shadows and Reflections

8 Light, Shadows and
Reflections

W
e see so many objects around all, it is an opaque object. If you are
us. On the way to school we able to see clearly through an object, it
see things like buses, cars, is allowing light to pass through it and
cycles, trees, animals and sometimes is transparent. There are some objects
flowers. How do you think, we see through which we can see, but not very
objects? clearly. Such objects are known as
Think of the same places at night translucent.
time if it were completely dark. What will
Activity 1
you see? Suppose you go inside a
completely dark room. Are you able to Look around yourself and collect as
see any objects in the room? many objects as you can — an eraser,
But, when you light a candle or a plastic scale, pen, pencil, notebook,
torch you can see the objects present in single sheet of paper, tracing paper or a
the room, isn’t it? Without light, things piece of cloth. Try to look at something
cannot be seen. Light helps us see far away, through each of these objects
objects. (Fig. 8.1). Is light from a far away object
The torch bulb is an object that gives able to travel to your eye, through any
out light of its own. The Sun, is another of the objects?
familiar object that gives its own light. Record your observations in a table
During the day, its light allows us to as shown in Table 8.1.
see objects. Objects like the sun that We see that a given object or material
give out or emit light of their own are could be transparent, translucent or
called luminous objects.
What about objects like a chair, a
painting or a shoe? We see these when
light from a luminous object (like the
Sun, a torch or an electric light) falls on
these and then travels towards our eye.
8.1 T RANSPARENT , O PAQUE AND
TRANSLUCENT OBJECTS
Recall our grouping objects as opaque,
transparent or translucent, in Chapter Fig. 8.1 Observing objects that do or do not
2. If we cannot see through an object at allow light to pass through them