Exploring Physical Changes

Physical Changes

Lesson Objectives

• Define physical changes after the activities.

• Tell the properties of physical changes after the investigation activities.

• State some real-life application of physical change.

Concept of Physical Changes

• Physical changes are changes that affect the physical properties of a substance without altering its chemical composition.
• Examples of physical changes include melting, boiling, freezing, and condensation.
• During physical changes, energy is either absorbed or released.
• Physical changes are reversible and do not create new substances.

Multiple Choice

Which of the following is an example of a physical change?

• Melting

• Burning

• Mixing with another substance

• Dissolving in water

Melting

Melting is an example of a physical change. It is the process of changing a substance from a solid to a liquid state by applying heat. During melting, the molecular structure remains the same, only the arrangement of particles changes. Other examples of physical changes include freezing, boiling, and condensation.

Characteristics of Physical Changes

• Physical changes are changes that affect the physical properties of a substance.
• They do not result in the formation of new substances.
• Examples include changes in shape, size, color, texture, and state of matter.
• Physical changes are reversible and do not involve a change in chemical composition.

Multiple Choice

Which of the following is NOT an example of a physical change?

• Change in color

• Change in state of matter

• Formation of new substances

• Change in shape

Characteristics of Physical Changes

• No new substances is formed

• changes in color, state of matter, and shape.

• Physical changes are reversible,

• No energy is involved

• identity of substance is not lot

Examples of Physical Changes

• Boiling water: Water changing from a liquid to a gas
• Melting ice: Ice changing from a solid to a liquid
• Tearing paper: Paper being ripped into smaller pieces
• Burning wood: Wood turning into ash and smoke

Multiple Choice

Which process involves wood turning into ash and smoke?

• Boiling water

• Melting ice

• Tearing paper

• Burning wood

Burning Wood

Burning wood is a process where wood turns into ash and smoke. It releases heat and light energy. This process is also known as combustion and requires oxygen. Wood burning has been used for cooking, heating, and creating fire for thousands of years.

Understanding Melting

• Melting is a physical change where a substance changes from a solid to a liquid state.
• It occurs when the temperature of a substance reaches its melting point.
• During melting, the molecular structure of the substance remains intact.
• Heat energy is absorbed during melting, causing the particles to gain energy and move more freely.

Multiple Choice

What is melting?

• Change from solid to liquid state

• Change from liquid to solid state

• Change from gas to solid state

• Change from solid to gas state

Understanding Freezing

• Freezing is a physical change that occurs when a substance changes from a liquid to a solid state.
• During freezing, the particles of the substance slow down and arrange themselves into a fixed pattern.
• Temperature plays a crucial role in freezing, as substances freeze at specific melting points.
• Freezing is the reverse process of melting, where a solid changes into a liquid.

Multiple Choice

What is freezing?

• Change from liquid to solid state

• Change from solid to liquid state

• Change from gas to liquid state

• Change from gas to solid state