{"id":3820,"date":"2023-01-09T10:36:16","date_gmt":"2023-01-09T10:36:16","guid":{"rendered":"https:\/\/7thclass.deltapublications.in\/?page_id=3820"},"modified":"2025-08-21T11:27:12","modified_gmt":"2025-08-21T11:27:12","slug":"s-4-a-hot-and-cold","status":"publish","type":"page","link":"https:\/\/7thclass.deltapublications.in\/index.php\/s-4-a-hot-and-cold\/","title":{"rendered":"S-4.a Hot And Cold"},"content":{"rendered":"\n<h2 class=\"wp-block-heading has-text-align-center has-text-color\" style=\"color:#00056d;text-transform:uppercase\"><strong>Hot and Cold<\/strong><\/h2>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Hot and Cold | Class 7 | Delta Publications\" width=\"620\" height=\"349\" src=\"https:\/\/www.youtube.com\/embed\/ZvMJRJu777s?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p class=\"has-text-color has-huge-font-size\" style=\"color:#74008b\"><strong>Key Notes :<\/strong><\/p>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Definition of Temperature<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Temperature is a measure of how hot or cold an object is. It indicates the level of heat energy present in an object.<\/li>\n\n\n\n<li>It is measured in units like <strong>Celsius (\u00b0C)<\/strong>, <strong>Fahrenheit (\u00b0F)<\/strong>, and <strong>Kelvin (K)<\/strong>.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Hot vs. Cold<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"875\" height=\"491\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-42.png\" alt=\"\" class=\"wp-image-14790\" style=\"aspect-ratio:1.7820773930753564;width:506px;height:auto\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-42.png 875w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-42-300x168.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-42-768x431.png 768w\" sizes=\"auto, (max-width: 875px) 100vw, 875px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li><strong>Hot objects<\/strong> have a higher temperature, while <strong>cold objects<\/strong> have a lower temperature.<\/li>\n\n\n\n<li>Our sense of touch can be misleading; we need thermometers for accurate temperature measurement.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Thermometers<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1012\" height=\"1024\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-43-1012x1024.png\" alt=\"\" class=\"wp-image-14791\" style=\"aspect-ratio:0.98828125;width:270px;height:auto\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-43-1012x1024.png 1012w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-43-297x300.png 297w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-43-768x777.png 768w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-43.png 1459w\" sizes=\"auto, (max-width: 1012px) 100vw, 1012px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Devices used to measure temperature.<\/li>\n\n\n\n<li><strong>Clinical thermometers<\/strong> are used for measuring human body temperature.<\/li>\n\n\n\n<li><strong>Laboratory thermometers<\/strong> measure a wider range of temperatures, useful in scientific experiments.<\/li>\n\n\n\n<li><strong>Digital thermometers<\/strong> have replaced mercury-based ones due to safety concerns.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Heat and Its Transfer<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Heat is a form of energy that flows from a <strong>hotter object to a colder object<\/strong>.<\/li>\n\n\n\n<li><strong>Conduction, convection<\/strong>, and <strong>radiation<\/strong> are the three modes of heat transfer.\n<ul class=\"wp-block-list\">\n<li><strong>Conduction<\/strong>: Heat transfer through direct contact (e.g., metal spoon in hot soup).<\/li>\n\n\n\n<li><strong>Convection<\/strong>: Heat transfer through fluids (liquids and gases) due to movement (e.g., boiling water).<\/li>\n\n\n\n<li><strong>Radiation<\/strong>: Heat transfer through electromagnetic waves (e.g., warmth from the sun).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Effects of Heat<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li><strong>Expansion<\/strong>: Objects expand when heated and contract when cooled.<\/li>\n\n\n\n<li><strong>Change in State<\/strong>: Heat can cause substances to change states, like <strong>melting<\/strong> (solid to liquid), <strong>evaporation<\/strong> (liquid to gas), and <strong>condensation<\/strong> (gas to liquid).<\/li>\n\n\n\n<li><strong>Thermal Energy<\/strong>: The total kinetic energy of all particles in a substance.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Temperature Scales<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li><strong>Celsius (\u00b0C)<\/strong>: Water freezes at 0\u00b0C and boils at 100\u00b0C.<\/li>\n\n\n\n<li><strong>Fahrenheit (\u00b0F)<\/strong>: Water freezes at 32\u00b0F and boils at 212\u00b0F.<\/li>\n\n\n\n<li><strong>Kelvin (K)<\/strong>: Absolute zero (0 K) is the lowest possible temperature, where all molecular motion stops. Water freezes at 273 K and boils at 373 K.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Heat vs. Temperature<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"841\" height=\"505\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-44.png\" alt=\"\" class=\"wp-image-14795\" style=\"aspect-ratio:1.6653465346534653;width:510px;height:auto\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-44.png 841w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-44-300x180.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-44-768x461.png 768w\" sizes=\"auto, (max-width: 841px) 100vw, 841px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li><strong>Heat<\/strong> is the total energy of molecular motion in a substance, while <strong>temperature<\/strong> is the measure of the average energy of molecular motion.<\/li>\n\n\n\n<li>Heat is measured in <strong>joules (J)<\/strong>, whereas temperature is measured in degrees.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#000060\"><strong>Everyday Examples<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>A hot cup of tea cools down over time as it loses heat to the surroundings.<\/li>\n\n\n\n<li>Ice melts when left out in the open due to heat absorption.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#d90000\"><strong>Let&#8217;s practice!<\/strong><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/wordwall.net\/play\/75972\/647\/690\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-3-16.png\" alt=\"\" class=\"wp-image-5889\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-3-16.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-3-16-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-3-16-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-3-16-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/wordwall.net\/play\/76019\/418\/806\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-2-13.png\" alt=\"\" class=\"wp-image-5890\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-2-13.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-2-13-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-2-13-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-2-13-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Hot and Cold Key Notes : Definition of Temperature: Hot vs. Cold: Thermometers: Heat and Its Transfer: Effects of Heat: Temperature Scales: Heat vs. Temperature: Everyday Examples: Let&#8217;s practice!<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"footnotes":""},"class_list":["post-3820","page","type-page","status-publish","hentry","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/3820","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/comments?post=3820"}],"version-history":[{"count":27,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/3820\/revisions"}],"predecessor-version":[{"id":15345,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/3820\/revisions\/15345"}],"wp:attachment":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/media?parent=3820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}