Effects of Heat

Effects of Heat
1
© Jnana Prabodhini Educational Resource Centre

There are three types of item solid, liquid and
gas. Wax , snow are examples of solid.
Examples of liquid are water , milk, oil .
Examples of gas are air, steam .
2

We can see the change in solid , liquid , gas if they are heated.
When heat given to solids it's size varies , and converted in to fluid . When
heat is given to liquids it start boiling and converted to gas form . If heat is
provided to gas it is expand.
3

If heat is provided in all three stages first of all the temperature of
substance increases . Then at specific temperature solid changes to
liquid and liquid changes to gas . The change in physical state of
substance due to heat is called as transition of foods .
4

When heat is given to item , it changes its state similarly if heat is taken out
from item it changes its state. If heat is taken out or cool down it changes it's
state to water. If water is cooled down it changes to ice. If ice is cooled down
it becomes hard. To remove heat means cooling down substance , due to
cooling the temperature of substance decreases.
5

To change the state of item either heat need to be provided or heat need to
be taken out.
Changing the state from solid to liquid is called as liquefaction
6

The temperature at which the substance changes its state from solid to
liquid is called as melting point of the substance . The temperature at
which liquid changes to gas state is called as boiling point of the
substance.
7

The process in which substance changes its state from gas to
liquid is called as condensation. The process in which
substance changes its state from liquid state to solid state is called
as freezing. The temperature at which substance changes its state
from liquid to solid is called as freezing point of the substance.
8

The unit to measure temperature is degrees Celsius (°c)
The melting point of ice is 0°c (zero degrees Celsius ).
The boiling point of water is 100°c (hundred degrees Celsius ).
The freezing point of water is 0°c (zero degrees Celsius).
9

If ice is heated it changes to the water. While the ice began to heat its
temperature is zero degrees Celsius. If a substance is heated it
should show rise or increase in the temperature of the substance. But
if ice is heated it started its transition and changes to water but does
not seem to increase temperature of ice . The temperature of the ice
stays 0°c until the transition of water completes.
10

After completing the transition of ice through water if
heating continues the water temperature seems to rise.
While solid substance changes to liquid , we can not see
the rise in temperature. It is used for the transition .
11

If water is heated it starts boiling at 100°c and converts to
steam.
This time it does not show rise in temperature. It is used for
the transition .
12

If solid substance is heated , expansion occur before
converting to fluid .The heat increases the length of iron
rod due to expansion. It is seen , measured on the lever
fixed on stand.
If a coin is heated, it also expands. A coin passing
through two nails can not pass through after heating it
because it is expanded and the size is increased, Can
pass through again after cooling.
13

Different solid substances of different materials expand differently.
If a strip of iron and copper is heated it bends towards iron
because expansion of copper is more then expansion of iron .
Such cables are used to maintain the temperature of the electronic
devices.
14

If liquid is heated it expands. It can be checked by take a test tube
filled with colored water and put hair tube in it.
When water is heated it expands. Notice the increased of water
level in a hair tube .
When milk is heated it seems coming up.
After cooling down the water level and milk level comes down.
15

If gas is heated it expands.
Fix a balloon on a narrow mouth glass bottle. Now heat the
glass bottle , the air in the bottle expands and enters in the
balloon and the balloon is expanded. If heating the glass
bottle is stopped the air cools slowly and it remains as it
was.
16

If substance is heated it expands similarly if
heat is taken out of substance it contracts.
17

To know the heat in a substance or level of temperature
thermometer is used.
The properties of expansion and contraction of substance due
to heat is used in thermometer.
18

Thermometer consist of a very small glass tube, which is narrow
at the top and has a small balloon of glass at the bottom. It is
filled with Mercury.
19

Mercury is a liquid sparkling substance ( metal).
It can be seen from distance, and does not stick to glass.
It’s freezing point is minus thirty nine degree Celsius and boils at
three hundred and fifty seven degree Celsius. This means -It can
show temperature difference between -39°c to 350°c .
It expands and contracts for small heat also.
It’s expansion and contraction is uniformly.
20

The base on which the thermometer is fixed has marks from 0°c to
100 °c.
While marking this, the balloon full of Mercury is dipped in boiling
water.
Mercury expands and level of mercury in the tube increases.
The level at which the Mercury is stable is marked as 100°c.
21

When the balloon of thermometer is dipped in ice the level of Mercury in
the tube decreases.
The level at which it is stable is marked as 0°c.
The distance between 0°c to 100 °c is divided into 100 equal part and
are marked.
One part is 1 °c.
22

If a substance is heated , the increase in temperature is depend on
following parts
Duration of heat – More the duration more the increase in temperature.
Volume of substance – If the volume of substance is less the increase in
temperature is early.
Format of substance – some items heated slowly and some heated fast.
23

Different substances shows different increase in temperature if same
amount of heat is provided.
If we have to increase temperature of different substances of same
volume with 1°c , the amount of heat is different.
24

Heat required to increase the temperature of a
substance by 1°c is called as calories of the
substance.
25

Heat required to increase temperature of 1 Kg
substance by 1°c is called as specific heat of the
substance.
26

While making appliances which work in high temperature
care should be taken for calories required and specific heat of
substances.
Example : Engine of a vehicle , Geyser, Heater, many more electric
appliances.
27

Heat Level is measured in Celsius and heat calories is
measures in Kilo grams.
1 Kilo Calorie = 1000 Calories
Heat required to increase temperature of 1 Kg. of water with
1°c is called as 1 kilo Calories.
To increase temperature of 1 gram of water with 1°c is 1
Calorie.
28

If cold water is mixed with hot water , hot water gives
out heat and cold water receives heat till the
temperature of all water becomes equal.
When hot and cold items come in contact with each
other there is give and take of heat. This is called as
heat transformation.
29

Heat Transformation
Heat given by hot substance = Heat received by cold
substance.
Heat transformation is depend on following things
Volume of substance
Specific heat of the substance
Temperature difference of the substance
30

A device used to study the heat transfer and to count
specific heat of substance is called as Calorimeter.
31

Calorimeter is made up of copper vassal fixed in a wooden
pot with wooden particles and other heat resistance
material to fill the gap between two containers. The lid of
the outer pot is made out of heat resistance material. The
lid has two holes one for thermometer and other for stirrer
to keep in copper vassal.
32

The copper vassal of
calorimeter is filled with hot /
cold water.
The substance of which
specific heat is to be
measured is put either hot or
cold into the calorimeter.
(Solid)
The mixer is stir till the
temperature of all the mixture
becomes same. The before
and after temperature is noted
using the thermometer.
Using proper formula Specific
Heat of substance is
calculated.
33

Effects of Heat

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Effects of Heat

Similar to Effects of Heat (20)

More from Jnana Prabodhini Educational Resource Center

More from Jnana Prabodhini Educational Resource Center (20)

Recently uploaded

Recently uploaded (20)

Effects of Heat