"Melting and Solidification" Changes in State of Matter PPT Courseware 4

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"Melting and Solidification" Changes in State of Matter PPT Courseware 4

The source of the Yangtze River—Geladandong Snow Mountain

The Yangtze River is the largest river in our country. "The Yangtze River rolls in endlessly." Looking at this majestic and surging river, have you ever thought that the original water source of this endless stream is actually Geladandong? Drops of water after melting snow on snowy mountains.

question:

1. Have you ever seen water freeze and ice melt into water?

The process by which we change matter from liquid to solid is called solidification

The process by which we change matter from solid to liquid is called melting

What else do you know about melting phenomena?

Thinking: What conditions do you think the above two processes require?

Do different substances melt and solidify in the same way?

Crystalline and amorphous

Crystal: A solid that has a certain melting temperature and absorbs heat during the melting process but the temperature remains unchanged.

Amorphous: a solid that does not have a certain melting temperature and whose endothermic temperature continues to rise during the melting process

Melting point/°C of some substances (at standard atmospheric pressure)

Thoughts: Why can’t you use an aluminum pot to melt iron?

Different crystals generally have different melting points, that is, the melting point is a characteristic of the crystal itself, which can be used to identify substances.

1. As shown in the figure is the melting image of the sea wave. Based on this image, reasonable information can be obtained.

Information 1: The initial temperature of sea waves is 25°C;

Information 2: Ocean waves are crystals;

Information 3: The melting point of sea wave is 48℃.

2. The figure shows the temperature changes with time during the dissolution process of ice cubes at -10°C after being heated.

(1) The ice cube is in __________ state within the first 5 minutes of heating.

(2) Within 5-15 minutes, the ice gradually __________, which means __________ and __________ coexist.

(3) By 20 minutes, all the ice has turned into water at __________℃

3. In the winter when the temperature is -20°C, the upper surface temperature of the ice on the river is ＿＿＿＿＿℃, and the lower surface temperature of the ice is ＿＿＿℃

4. Place the ice-water mixture in a room at -2°C. It will:

A. Continue to melt B. Continue to solidify

C. Neither melts nor solidifies D. Unable to judge

5. As shown in the picture, insert the test tube containing crushed ice cubes into the crushed ice cubes in the beaker, and then slowly heat the bottom of the beaker. When the ice cubes in the beaker are half melted, the ice cubes in the test tube will ( )

A. All melted B. Does not melt

C. Melted half D. start to melt

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For more information about the "Melting and Solidification Changes in State of Matter" PPT courseware, please click the Melting and Solidification ppt Changes in State of Matter ppt tag.

"Melting and Solidification" PPT courseware:

Contents of the first part of the PPT courseware "Melt and Solidify": Three states of matter: Take water as an example: ice rain, white gas, fog, dew, frost, snow, hail Water vapor Solid state: ice, frost, snow and hail Liquid state: rain, fog, dew, white gas Gaseous state: water Vapor (invisible to the human eye) ... ...

"Melting and Solidification" PPT:

"Melt and Solidification" PPT Part 1 Content: State Changes Solid, liquid, and gaseous states are the three common states of matter. Solid state: such as aluminum, gold, silver, copper, iron, etc. are usually solid. Liquid state: such as water, vinegar, oil, etc. are usually liquid. Gaseous state: such as oxygen, hydrogen,...

"Exploring the Characteristics of Melting and Solidification" Material Forms and Their Changes PPT Courseware 2:

"Exploring the Characteristics of Melting and Solidification" Material Form and Its Changes PPT Courseware 2 Learning Objectives 1. Know what melting and solidification are. Understand the endotherms of melting and the exotherms of solidification. Know the characteristics of crystalline and amorphous melting and solidification. Understand the physical meaning of melting curves. 2. know..

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Update Time: 2024-11-25

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 1 industry PPT template

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