SX05_BkK_AdRdStdyWkBk.fm Page 22 Monday, April 18, 2005 8:09 AM
Name
Date
Solids, Liquids, and Gases
■
Class
Adapted Reading and Study
Changes of State
(pages 48–53)
Changes Between Solid and Liquid
(pages 49–50)
Key Concept: At its melting point, the particles of a
solid substance are vibrating so fast that they break
free from their fixed positions. At its freezing
temperature, the particles of a liquid are moving so
slowly that they begin to form regular patterns.
• When a solid changes to a liquid, the solid is melting.
Solid ice melts in warm temperatures and forms liquid
water.
• When a solid gains thermal energy, the particles of the
solid move in place faster. When enough energy is
added, the particles break away from their places.
• When a liquid changes to a solid, the liquid is freezing.
Freezing is just the reverse of melting. Liquid water
freezes in very cold temperatures and forms ice.
• When a liquid loses thermal energy, the particles of the
liquid slow down. Over time, the particles move into
fixed places. Then, the liquid becomes solid.
Answer the following questions. Use your textbook and the
ideas above.
1. Read each word in the box. In each sentence below, fill
in the correct word or words.
melting
freezing
thermal energy
a. When a liquid changes to a solid, the liquid is
.
b. When a solid changes to a liquid, the solid is
.
© Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved.
22
SX05_BkK_AdRdStdyWkBk.fm Page 23 Monday, April 18, 2005 8:09 AM
Name
Date
Solids, Liquids, and Gases
■
Class
Adapted Reading and Study
2. Fill in the words in the table below to show the
relationship between energy and the movement of
particles.
Changes Between Solid and Liquid
Change of
State
Thermal
Energy
Particles Move
Melting
added or gained
b.
Freezing
a.
slower
3. Is the following sentence true or false? When a liquid
becomes a solid, it gains thermal energy.
Changes Between Liquid and Gas
(pages 50–52)
Key Concept: Vaporization takes place when the
particles in a liquid gain enough energy to form a gas.
Condensation occurs when particles in a gas lose
enough thermal energy to form a liquid.
• The change from a liquid to a gas is called vaporization
(vay puhr ih ZAY shun). At high temperatures, water
changes to water vapor. When a puddle of water
disappears on a hot, sunny day, the water has changed
to water vapor.
• When a liquid gains thermal energy, the particles of the
liquid move faster. When enough energy is added, the
particles spread far apart. Then, the liquid becomes a
gas.
© Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved.
23
SX05_BkK_AdRdStdyWkBk.fm Page 24 Monday, April 18, 2005 8:09 AM
Name
Date
Solids, Liquids, and Gases
■
Class
Adapted Reading and Study
• The change from a gas to a liquid is called
condensation (kahn dehn SAY shun). When water
vapor cools, it becomes liquid water. Dew on the grass
in the morning is water vapor in the air that has cooled
and become a liquid.
• When gas particles lose thermal energy, they slow
down. As the particles slow down, the particles move
closer together and form a liquid.
Answer the following questions. Use your textbook and the
ideas on page 23 and above.
4. Look at the pictures below. One shows a puddle of
water on a sunny day. The other shows drops of dew on
grass. Circle the letter of the picture in which
vaporization is occurring.
a.
b.
5. Read each word in the box. In each sentence below, fill
in one of the words.
make
gain
lose
a. Vaporization takes place when liquid particles
thermal energy.
b. Condensation takes place when gas particles
c.
thermal energy.
© Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved.
24
SX05_BkK_AdRdStdyWkBk.fm Page 25 Monday, April 18, 2005 8:09 AM
Name
Date
Solids, Liquids, and Gases
■
Class
Adapted Reading and Study
Changes Between Solid and Gas
(page 53)
Key Concept: During sublimation, particles of a solid
do not pass through the liquid state as they form a
gas.
• The direct change from a solid to a gas is called
sublimation (suhb luh MAY shun). In sublimation, the
solid never changes to a liquid. When snow seems to
disappear without melting, sublimation has taken place.
• Sublimation takes place when particles on the surface of
a solid gain enough thermal energy to break away. The
particles have enough energy to spread far apart and
form a gas.
Answer the following question. Use your textbook and the
ideas above.
6. Is the following sentence true or false? In sublimation, a
solid becomes a liquid first, then a gas.
© Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved.
25