https://www.khanacademy.org/science/ms-chemistry/xc370bc422b7f75fc:physical-properties-of-matter/xc370bc422b7f75fc:intrinsic-and-extrinsic-properties/v/physical-changes 2025-02-13T17:59:34.347326855Z Physical changes Physical changes alter the appearance or state of matter without changing its identity. Whether bending copper wire, crushing salt, freezing water, or dissolving salt into water, the substances retain their original forms, like H₂O or NaCl. Understanding physical changes helps identify substances through properties like melting and boiling points, which are inherent and consistent across samples. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/d873dd6b-08cf-4f7e-8fc0-4d02e97127ad_1280_720_base.png Physical changes Physical changes alter the appearance or state of matter without changing its identity. Whether bending copper wire, crushing salt, freezing water, or dissolving salt into water, the substances retain their original forms, like H₂O or NaCl. Understanding physical changes helps identify substances through properties like melting and boiling points, which are inherent and consistent across samples. https://cdn.kastatic.org/ka-youtube-converted/jn-skkO5NNI.mp4/jn-skkO5NNI.mp4 318 Intro to Physical and Chemical changes https://www.khanacademy.org/science/ms-chemistry/xc370bc422b7f75fc:chemical-changes/xc370bc422b7f75fc:chemical-changes-ms/v/chemical-changes 2025-03-21T20:29:57.678923887Z Chemical changes A chemical change occurs when a substance transforms into one or more new substances with different properties. Chemical reactions often involve color changes, gas production, odor changes, precipitate formation, or energy changes like heat or light. Unlike physical changes, chemical changes alter a substance’s identity, making them key to understanding chemical properties. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/3665da2c-e708-41b0-a732-779264ca6d87_1280_720_base.png Chemical changes A chemical change occurs when a substance transforms into one or more new substances with different properties. Chemical reactions often involve color changes, gas production, odor changes, precipitate formation, or energy changes like heat or light. Unlike physical changes, chemical changes alter a substance’s identity, making them key to understanding chemical properties. https://cdn.kastatic.org/ka-youtube-converted/CT5CVpOVAoY.mp4/CT5CVpOVAoY.mp4 445 Intro to Physical and Chemical changes https://www.khanacademy.org/science/revision-term-1-ka-science-class-7/x05832cca8e86a1ef:week-2/x05832cca8e86a1ef:physical-and-chemical-changes/e/difference-between-physical-and-chemical-changes 2025-04-16T07:50:43.571832077Z What is a physical and chemical change? Let's solve some questions on the physical and chemical changes   Vibhor Pandey exercise