Changes Around Us: Physical and Chemical
CBSE · Class 7 · Science
Summary of Changes Around Us: Physical and Chemical for CBSE Class 7 Science. Key concepts, important points, and chapter overview.
Overview
In our daily life, we observe various changes happening around us constantly. From ice melting to water, flowers blooming from buds, vegetables being cooked, to iron rusting - these are all examples of changes. This chapter helps us understand and classify these changes into two main categories: phy
Key Concepts
A change in which only
A change in which only the physical properties (like shape, size, state) of a substance change, but no new substance is formed. Examples include melti
A change in which one
A change in which one or more new substances are formed through a chemical reaction. Examples include burning wood, rusting of iron, curdling of milk,
A chemical reaction where a substance
A chemical reaction where a substance reacts with oxygen to produce heat and/or light, forming new substances. It requires three things: a combustible
The minimum temperature at which
The minimum temperature at which a substance catches fire and starts burning. Different substances have different ignition temperatures, which explain
Reversible changes can be undone
Reversible changes can be undone to get back the original substance (like melting and freezing ice). Irreversible changes cannot be undone (like burni
Learning Objectives
- Identify and classify changes as physical or chemical changes
- Understand the characteristics and properties of physical and chemical changes
- Learn about combustion and its requirements (fuel, oxygen, and ignition temperature)
- Distinguish between reversible and irreversible changes
- Recognize desirable and undesirable changes in daily life
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What are the important topics in Changes Around Us: Physical and Chemical for CBSE Class 7 Science?
Changes Around Us: Physical and Chemical covers several key topics that are frequently asked in CBSE Class 7 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Changes Around Us: Physical and Chemical — CBSE Class 7 Science?
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Sources & Official References
- NCERT Official — ncert.nic.in
- CBSE Academic — cbseacademic.nic.in
- CBSE Official — cbse.gov.in
- National Education Policy 2020 — education.gov.in
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
Previous Chapter
The World of Metals and Non-metals
Next Chapter
Adolescence: A Stage of Growth and Change
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