https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:chemical-reactions/x8bc8fb44369617ed:physical-and-chemical-changes/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 Differences between physical and chemical changes https://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiome/balancing-chemical-equations/v/chemical-reactions-introduction 2021-04-11T17:58:19Z Chemical reactions introduction Reactants and products in reversible and irreversible chemical reactions. video https://cdn.kastatic.org/googleusercontent/sOAB7bEWaCpnU94w4SBtJMJRngkzJJM19enomEj_DjdKizQ4PcjKW8uzQ5GItii7yeMnOf8Gxaa_ZLbYDhDrtKM Chemical reactions introduction Reactants and products in reversible and irreversible chemical reactions. https://cdn.kastatic.org/ka-youtube-converted/TStjgUmL1RQ.mp4/TStjgUmL1RQ.mp4 553 Differences between physical and chemical changes https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:chemical-reactions/x8bc8fb44369617ed:physical-and-chemical-changes/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 Differences between physical and chemical changes https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:chemical-reactions/x2613d8165d88df5e:representing-chemical-reactions/v/physical-and-chemical-changes 2023-12-15T18:39:28.793791463Z Physical and chemical changes Physical and chemical processes can be classified by the changes occurring on the molecular level. In general, chemical processes involve changes in chemical bonds, while physical processes involve changes only in intermolecular forces. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/13f405e4-0927-4fb9-9b5e-913f069d17f9_1280_720_base.png Physical and chemical changes Physical and chemical processes can be classified by the changes occurring on the molecular level. In general, chemical processes involve changes in chemical bonds, while physical processes involve changes only in intermolecular forces. https://cdn.kastatic.org/ka-youtube-converted/n5cZ5CWuUJA.mp4/n5cZ5CWuUJA.mp4 279 Differences between physical and chemical changes https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:chemical-reactions/x8bc8fb44369617ed:physical-and-chemical-changes/e/physical-and-chemical-changes-in 2026-04-08T00:54:09.631945657Z Physical and Chemical changes Let's practice! vibhor exercise https://www.khanacademy.org/science/grade-7-science-snc-aligned/x64f379bc07a3640a:physical-and-chemical-changes/x64f379bc07a3640a:differences-between-physical-and-chemical-changes/v/melting-wax-vs-burning-candle-ur 2025-08-08T00:24:37.843818748Z Melting wax vs Burning candle Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Melting wax vs Burning candle Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/CDQKdculxtI.mp4/CDQKdculxtI.mp4 275 Differences between physical and chemical changes https://www.khanacademy.org/science/grade-7-science-snc-aligned/x64f379bc07a3640a:physical-and-chemical-changes/x64f379bc07a3640a:differences-between-physical-and-chemical-changes/v/salt-in-water-vs-burning-magnesium-ur 2025-08-08T00:24:37.843818748Z Salt in water vs Burning magnesium Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Salt in water vs Burning magnesium Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/z99tYOjhXcA.mp4/z99tYOjhXcA.mp4 196 Differences between physical and chemical changes https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:metals/x8bc8fb44369617ed:corrosion-of-metals/v/heating-iron-vs-rusting-iron-ur 2025-08-08T00:24:37.843818748Z Heating iron vs rusting iron Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Heating iron vs rusting iron Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/s3jFV2IT8kc.mp4/s3jFV2IT8kc.mp4 112 Differences between physical and chemical changes https://www.khanacademy.org/science/grade-7-science-snc-aligned/x64f379bc07a3640a:physical-and-chemical-changes/x64f379bc07a3640a:differences-between-physical-and-chemical-changes/v/deformation-vs-food-spoilage-ur 2025-08-08T00:24:37.843818748Z Deformation vs Food Spoilage Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Deformation vs Food Spoilage Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/bF9PHZEPm20.mp4/bF9PHZEPm20.mp4 149 Differences between physical and chemical changes https://www.khanacademy.org/science/grade-7-science-snc-aligned/x64f379bc07a3640a:physical-and-chemical-changes/x64f379bc07a3640a:differences-between-physical-and-chemical-changes/v/dissolving-sugar-vs-burning-sugar-ur 2025-08-08T00:24:37.843818748Z Dissolving sugar vs Burning sugar Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Dissolving sugar vs Burning sugar Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/c4q_UGNBpqA.mp4/c4q_UGNBpqA.mp4 134 Differences between 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/physical-and-chemical-changes-in-daily-life 2026-04-07T22:59:30.107127435Z Identify if a change is physical or chemical Let's solve some questions on distinguishing physical and chemical changes in daily life Vibhor Pandey exercise 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