2. ENERGY
• ability to do work and make things happen.
• We use energy in our daily activities.
• We cannot be able to do a lot of things without energy.
• Kinds of Energy like:
– light energy enable us to see things
– sound energy enable us to hear the different sounds around us
– Heat energy keeps us warm
3.
4.
5. SOURCES OF LIGHT
• Light sources – things that provide light.
• It can be:
–natural or
–artificial
6. those that are not produced by people.
Primary source of natural light is the sun,
which produces large amount of light
energy.
Other stars also produce light energy,
although Earth receives this in smaller
amounts compared to that from the sun
because they are much farther from the
Earth.
The moon is also another source
although its light is just reflected from
the sun.
7. Natural light energy can also come from some animals such as
fireflies, glowworms, jellyfish, and fishes from deep parts of the
sea.
These animals have body parts that give off flashes of light in
the dark.
8. those that people create.
Ex:
Electric bulbs
Flashlight
Candles
lamp
11. Light travels in a
straight line.
It is transmitted
when nothing gets
in the way of this
line.
12. Sometimes an
object may block the
path of light.
When this happens,
the object forms a
shadow – or dark
shape that is created
on the areas
surrounding the
object.
The size of a shadow
depends on the
object’s distance
from the source of
light.
14. Shadows are
formed when light
is not able to pass
through an object
that is opaque.
Opaque materials
do not allow to pass
through them.
Ex: human body,
wood, and
rubber
18. When you look at a shiny
object, you may clearly see
your image in it because of
the light that strikes the
object.
The image that you see is your
reflection or mirror image.
When light strikes a shiny
surface or object a certain
angle, waves of the light
bounce off in the same angle.
It is a phenomenon of light
bouncing back from a surface
demonstrates the behavior of
light.
19. Light travels at a very fast rate.
However, this speed slows
down when light travels
through an object, such as the
glass and water in the
photograph.
It is a phenomenon where
there is the decrease in the
speed of its travel results in
light being bent.
Ex: placing the pencil into a
glass of water and taking it
out (see the differences);
rainbow
20. Sunlight is the source of vitamin D, which helps to make
your bones and skin healthy but too much exposure from
it can also damage the skin and eyes.
It is because sun emits some very strong rays, called
ultraviolet rays – which can cause the skin to burn or tan
too much can hurt the eyes.
Thus, it is a must to:
Apply sunscreen lotion
Use an umbrella when staying out in the sun for a long
time
Do not look at the sun with your bare eyes
Wear some eye protection such as sunglasses
