Heat Book Back Questions 6th Science Lesson 8

6th Science Lesson 8

8] Heat

Book Back Questions with Answer and Do You Know Box Content

Do You Know?

One day in 1922, the air temperature was measured at 59^oC in the shade in Libya, Africa. The coldest temperature in the world was measured in the Antarctic continent. It was approximately –89^oC. The minus sign (-) is used when the temperature falls below the freezing point of water, which is 0^oC. If water becomes ice at 0^oC, you can imagine how cold -89^oC would be. Our normal body temperature is 37^oC. Our body feels cool if the air temperature is around 15 to 20 degree Celsius.

Glassware used in kitchen and laboratory are generally made up of Borosilicate glass (pyrex glass). The reason is that the Borosilicate glasses do not expand much on being heated and therefore they do not crack.

Choose the best answers:

1. When an object is heated, the molecules that makes up the object

(a) Begin to move faster

(b) Lose energy

(c) Become heavier

(d) Become lighter

2. The unit of heat is

(a) Newton

(b) Joule

(c) Volt

(d) Celsius

3. One litre of water at 30^oC is mixed with one litre of water at 50^oC. The temperature of the mixture will be

(a) 80^oC

(b) More than 50^oC but less than 80^oC

(c) 20^oC

(d) Around 40^oC

4. An iron ball at 50^oC is dropped in a mug containing water at 50^oC. The heat will

(a) Flow from iron ball to water

(b) Not flow from iron ball to water or from water to iron ball

(c) Flow from water to iron ball

(d) Increase the temperature of both

Fill in the blanks:

1. Heat flows from a ____________ body to a ___________ body.

2. The hotness of the object is determined by its ___________

3. The SI unit of temperature is __________

4. Solids ____________ on heating and __________ on cooling.

5. Two bodies are said to be in the state of thermal ________________ if there is no transfer of heat taking place.

State true or false. If false, correct the statement:

1. Heat is a kind of energy that flows from a hot body to a cold body.

2. Steam is formed when heat is released from water.

3. Thermal expansion is always a nuisance.

4. Borosilicate glass does not expand much on being heated.

5. The unit of heat and temperature are the same.

Match the following:

1. Heat – 0^oC

2. Temperature – 100^oC

3. Thermal Equilibrium – Kelvin

4. Ice cube – No heat flow

5. Boiling water – Joule

Complete the analogy:

1. Heat: Joule :: Temperature: _______________

2. Ice cube: 0^oC :: Boiling water: ___________

3. Total Kinetic Energy of molecules: Heat :: Average Kinetic Energy: _____________

Answers:

Choose the best answers:

1. Begin to move faster 2. Joule 3. Around 40^oC 4. Not flow from iron ball to water or from water to iron ball

Fill in the blanks:

1. Hot, Cold 2. Kinetic energy 3. Kelvin 4. Expand, Contract 5. Equilibrium

Say True or False:

1. True

2. False

Correct Statement: Ice is formed when heat is released from water.

3. True

4. True

5. False

Correct Statement: The SI unit of heat is joule. The SI unit of temperature is Kelvin.

Match the following:

1. Joule 2. Kelvin 3. No heat flow 4. 0^oC 5. 100^oC

Complete the analogy:

1. Kelvin 2. 100 ^oC 3. Average heat