Grade 5 science 3rd quarter

1. Chapter 8

2. HEAT
The sun is earth’s main source of energy. The energy from the sun makes earth a perfect place
for living things to survive.
LESSON
1

3. Heat and Temperature
Heat refers to the energy that is transferred from one object to another. Heat is
different from temperature. Temperature refers to the hotness or coldness of an
object. A thermometer is used to measure temperature.
Hot object have a high temperature while cold objects have a low temperature.
Furthermore, the hotter an object is, the higher its temperature .
Boiling water has a
temperature of
100°𝑐
An ice cube has a
temperature of
0°𝐶

4. However, a hotter object does not necessarily
contain more heat and a colder object does
not necessarily contain less heat. Suppose you
need to warm a bucket of cold water for your
morning bath. Which will you mix with the
cold water ; a glass of 90°c hot water? Or a pot
of 70°c hot water? Use the pot of 70°c hot
water. Even though the glass of hot water has
a higher temperature, it is not enough to
make the water in the bucket warm; the pot of
70°c water has more energy to transfer to the
cold water?

5. The given example also shows that when two
objects with different temperatures are brought
in contact, energy is transferred- three is heat.
Heat flows from the hot object to the cold object.
When hot water and cold water are mixed, the
temperature of hot water decreases, while the
temperature of cold water increases. The transfer
of heat stops when the two object have the same
temperature. This is called thermal equilibrium.

6. Thermal Conductors and Thermal Insulators
Objects absorb heat at different rates. Object that can easily absorb heat are called thermal
conductors. Thermal conductors can transfer energy in the form of heat quickly and easily.
Meanwhile, objects that do not easily absorb heat are called thermal insulators. Plastics are good
thermal insulators. When heat is absorbed by plastic materials, heat is not transferred easily.

7. Try this! Pour the same amount of hot water into two identical glasses. Then, put a plastic spoon
in one glass and a metal spoon in the other. What do you think will happen to the spoon?
Which of the two spoons is a thermal
conductor? Which is a thermal
insulator?
Metal are good thermal conductors.
They heat easily. That why kitchen
wares like pans and pots are made of
metals.

8. Plastic are good thermal insulators.
When heat touches a plastic material,
it does not let the energy pass. The
handle of pans and pots are made of
plastic or wood that protect your hand
for getting burned.
Can you name some example of
conductors and insulators?
A frying pan is made of a
metal pan (conductor) and
a plastic handle (insulator).

9. LIGHT
Light from the sun travels in a straight path. Plans use this light to make their food through
photosynthesis. Light makes it possible for us to see the things around us.
LESSON
2

10. Components of light
When lights passes through a prism, light is separated into different colors- red, orange, yellow,
green, blue, indigo, and violet. Notice that these are the same colors that you see in a rainbow.
In fact, a rainbow is formed when a ray of light passes through a raindrop of water.

11. Light and How We See Things
What happens to the light that did not
pass trough the materials? Light colors
that did not pass through the
materials are either reflected back or
absorbed by the object.
Transparent, Translucent, and Opaque
When light strikes an object, light may
behave in three different ways.

12. Materials that let almost all (if not all) light
to pass through are transparent. You can
see through a transparent material, such as
glass. Since almost all light passes through
to the other side, objects behind a
transparent material can be seen clearly.
Materials that let some light to pass
through are translucent. Frosted glass is a
translucent material. Since only some light
can pass through to the other side, objects
behind a translucent material cannot be
seen clearly or appear blurred.

13. Material that do not let light to pass
through are opaque. Cardboard is an
opaque material. Since no light can
pass through to the other side, objects
behind an opaque material cannot be
seen.

14. Light is made up of different colors. When white light, like the light from the sun, strikes a glass
prism, it will send out light of various colors- from red, orange, yellow, green, blue, indigo, and
violet (ROYGBIV).
When light strikes an object, the
object may reflect some of the
light or all of it, or absorb some
of the light or all of it. The color
of light an object reflects is the
color your eyes see.
The sphere in the picture looks
red because it reflects the red
light and absorb all the colors.

15. If the object reflects all colors of the light, all colors of the light are transmitted
to the eyes, and the material will appear white. If the object absorbs all colors of
the light no light gets into the eyes, and the material will appear black.
Black is what you see when an object
absorbs all the colors.
White is what you see when an
object reflects all the colors.

16. You already know what happens to the light reflected by an object, but what happens the light
absorbed? Light is a form of energy. As light is reflected or absorbed by an object, energy is also
reflected or absorbed. The amount of energy that is absorbed by an object depends on the
color the object absorbs. The colors of the visible light are arranged in order-red has the longest
wavelength, while violet has the shortest.
Light, Color, and Temperature

17. The color wheel below shows the different brightness of the colors. Colors in the
same circle have the same brightness.
Different Brightness of
Colors