Ch.2.1

Question 1

Water is one of the most ________________ resources on Earth

Answer 1

Abundant.

Question 2

Water covers about ?% of the planet’s surface

Answer 2

70.

Question 3

Water can exist in __________ physical states.

Answer 3

Three.

Question 4

Which few states can water exist in?

Answer 4

1. Solid (ice)
   
   2. Liquid (water)
   3. Gas (water vapour or steam)

Question 5

Upon __________ or __________, water can change from one state to another.

Answer 5

Heating, cooling

Question 6

Water ____________ or ___________ energy when it changes its state.

Answer 6

Absorbs, releases

Question 7

Describe the change in state during the process of melting.

Answer 7

Solid->liquid

Question 8

What is the fixed temperature when ice melts called?

Answer 8

The melting point.

Question 9

The temperature of when ice melts is _____________.

Answer 9

0。C

Question 10

During the process of melting, the temperature remains _________.

Answer 10

Unchanged.

Question 11

When ice melts, it ____________ energy from surroundings.

Answer 11

Absorbs.

Question 12

What is the change in state of water during freezing?

Answer 12

Liquid->solid

Question 13

What is the fixed temperature when water freezes called?

Answer 13

The freezing point.

Question 14

The temperature of when ice freezes is ___________.

Answer 14

0。C

Question 15

During the process of freezing, the temperature remains ________.

Answer 15

Unchanged.

Question 16

When water freezes, it ___________ energy.

Answer 16

Releases.

Question 17

What is the change in state of water during the process of boiling?

Answer 17

Liquid->gas

Question 18

What is the fixed temperature when water boils called?

Answer 18

The boiling point.

Question 19

The temperature of when water boils is _______.

Answer 19

100。C

Question 20

During the process of boiling, the temperature remains ___________.

Answer 20

Unchanged.

Question 21

When water boils, it _____________ energy.

Answer 21

Absorbs.

Question 22

What is the change in form of water during evaporation?

Answer 22

Liquid->gas

Question 23

Evaporation takes place at ______________.

Answer 23

Any temperature.

Question 24

When water evaporates, it ____________ energy.

Answer 24

Absorbs.

Question 25

What is the change in state of water during condensation?

Answer 25

Gas->liquid

Question 26

When water vapour or steam condenses into water, it __________ energy.

Answer 26

Releases.

Question 27

Water on Earth keeps changing between its ______________—solid, liquid and gas.

Answer 27

Physical states.

Question 28

In Nature, water goes through a cycle called the _____________.

Answer 28

Water cycle.

Question 29

What is the first step of the water cycle?

Answer 29

Evaporation.

Question 30

Energy from ______________ powers the water cycle.

Answer 30

The Sun.

Question 31

Water from seas, rivers and on land __________ the energy from the ________ and evaporates to form _____________.

Answer 31

Absorbs, Sun, water vapour

Question 32

The ______________ is then carried upwards by __________ ______ beneath it.

Answer 32

water vapour, warm air

Question 33

What is the second step of the water cycle called?

Answer 33

Condensation.

Question 34

(Step 2 of water cycle) Higher in the sky, the _________ air cools the water vapour and it _____________ to form _________ __________, which join to form _____________.

Answer 34

Colder, condenses, water droplets, cloud

Question 35

(Step 3 of water cycle) The ___________ may be carried by ________ to other places.

Answer 35

Clouds, wind

Question 36

(Step 4 of the water cycle) As more water vapour ___________, the water droplets in the clouds grow ___________ and ___________. Eventually, they become so heavy that they fall as _______, ______ or ______.

Answer 36

Condenses, larger, heavier

Rain, snow, hail

Question 37

When the water absorbs energy from the Sun, it ________ again.

Answer 37

Evaporates.

Question 38

Water is cycled _______________.

Answer 38

Continuously.

Question 39

• The rate evaporation increases when:
  * The temperature is _________
  * The humidity is ________
  * There is more _________
  * The surface area exposed is _________

Answer 39

Higher,
Lower,
Airflow,
Larger