Physical and chemical changes_Grade7

• Chemistry
• Secondary Education
• Age 13

Physical and chemical changes

LEARNING OBJECTIVES

•  Differentiate physical and chemical changes.

• Analyze the characteristics of physical and chemical changes

What is a change?

wordwall.net

Activity

Take a sheet of paper. describe its color, odour, size, and shape. Now fold or tear the paper . 

What happened to the physical appearance of the paper?

 Does its color change? How about its odour? What happened to its size and shape?

Does the colour of the paper change?

YES

NO

What are the characteristics
of a physical change

What is a physical change?

Physical change is a change of matter without affecting the composition or the identity of a substance. The substance only changes size, shape, form, state, quantity, or mixed with other substances, but no new substance is formed and its composition stays the same.

Are all physical changes reversible?
Give examples.

Give two examples of Physical Change
based on what you have learned.

Is rusting a physical or chemical change?

Group Activity :Analyze and observe the characteristics of a chemical change. Complete the task sheet provided.

• Activity 1: To Observe the sample of apple and potato provided. 
• Activity 2: Demonstration of the reaction between baking soda and vinegar https://youtu.be/zbaIbnqkJZI
• Activity 3: • Burning of Magnesium Ribbon: https://youtu.be/k6C2dETQ0bw

What are the other characteristics of a chemical change?

Give some examples
of chemical changes

Physical Change

Chemical Change

Characteristics of chemical change

No new product is formed

New product is formed

Evolution of gas

Generation of light and sound

Only physical properties like shape, size, colour etc. of the substance changes.

Generation of characteristic smell

Only chemical properties and composition of the substance changes.

Create a Venn diagram to compare the characteristics of physical and chemical change.

Condensation of steam is a physical or chemical change? Justify your answer

LPG in a gas cylinder is in form of a liquid. Which physical and chemical changes occur when it burns?

1.Dissolving sugar in water is a_______ change

1. Physical change
2. Chemical change
3. Colour change
4. None of the above

2. Formation of curd is a __________change.

1. Physical Change
2. Chemical change
3. None of these
4. colour change

3.Adding salt to water makes it salty. Which of the following statement is true regarding this change?

1. It is a chemical change because a new substance is formed.
2. It is a physical change because the original substance can be recovered.
3. It is a chemical change because there is exchange of heat.
4. It is a physical change because there is a slight change in colour.

quizizz.com

I am able to differentiate between physical and chemical changes