We need light to see. When we walk into a dark
room we need turn on the light.
Light moves in a straight line.
Light moves very fast.
Some objects do not let light through. When light
cannot travel through an object, a shadow is
The shadow of an object is always formed on the
opposite side to the source of light.
We divide object into three groups depending on
how much light can pass through them.
Transparent objects, like clear glass bottles, allow light
to pass through.
We can see objects that are behind them.
Translucents objects, allow some light to pass
through, but we cannot see objects behind them very
clearly. Some curtains are translucent.
Opaque objects, for example wood and cardboard, do
not allow light to pass through.
Some objects are sources of light. We call them
Natural luminous bodies, like the Sun,produce
Artifical luminous bodies, like candles and
matches, are man-made.
Non-luminous bodies produce no light. Some
for these objects, like mirrors or the Moon
reflect the light that reaches them.
When we touch a hot object, our
hand feels hotter.
When we touch a cold object, our
hand feels colder.
Heat goes from one body to
Heat goes from hot bodies to colder
Our food cools on a plate because
the heat goes into air.
Some materials get hotter or colder more
quickly than others. If we put a piece of iron
and a piece of wood in the Sun the piece of iron
gets hot more quickly.
Materials like iron, aluminium and glass are
conductors. They get hot and cold quicky.
Materials like wood and plastic are insulators.
They get hot and cold slowly.