--- title: 7-MS-PS1-5 description: 7-MS-PS1-5 Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. image: https://www.knowatom.com/hubfs/Right%20Image.png --- [![Teacher Login](https://no-cache.hubspot.com/cta/default/347944/f56bee57-133e-4975-8055-799f1f23588b.png)](https://cta-redirect.hubspot.com/cta/redirect/347944/f56bee57-133e-4975-8055-799f1f23588b) [Teacher Login](https://app.knowatom.com/signin) [![KnowAtom Logo](https://www.knowatom.com/hubfs/KnowAtom%20Logo.svg "KnowAtom Logo")](https://www.knowatom.com/) # 7-MS-PS1-5 Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. [![Download a Sample Unit](https://no-cache.hubspot.com/cta/default/347944/20eee377-e175-48fe-a039-ae723137a2a6.png)](https://cta-redirect.hubspot.com/cta/redirect/347944/20eee377-e175-48fe-a039-ae723137a2a6) Science & Engineering Practices - [Developing and using models](https://www.knowatom.com/developing-and-using-models) - [Planning and carrying out investigations](https://www.knowatom.com/planning-and-carrying-out-investigations) - [Constructing explanations and designing solutions](https://www.knowatom.com/constructing-explanations-and-designing-solutions) - [Engaging in argument from evidence](https://www.knowatom.com/engaging-in-argument-from-evidence) - [Obtaining evaluating and communicating information](https://www.knowatom.com/obtaining-evaluating-and-communicating-information) Disciplinary Core Ideas - [Weather and Climate](https://www.knowatom.com/weather-and-climate) - [Conservation of Energy and Energy Transfer](https://www.knowatom.com/conservation-of-energy-and-energy-transfer) Crosscutting Concepts - [Patterns](https://www.knowatom.com/patterns) - [Cause and Effect](https://www.knowatom.com/cause-and-effect) [![New call-to-action](https://no-cache.hubspot.com/cta/default/347944/b5a1446e-d782-4a5f-a019-0b3b98c8304f.png)](https://cta-redirect.hubspot.com/cta/redirect/347944/b5a1446e-d782-4a5f-a019-0b3b98c8304f) ## Browse 7-MS-PS1-5 Lesson Plans Grade Ranges All K-2 3-5 6-8 [![](https://www.knowatom.com/hubfs/Grade/Screenshot%20(32).png) ](https://www.knowatom.com/science-phenomena-videos/7th-grade-science/the-rock-cycle) ## [The Rock Cycle In this unit, students use what they know about the relationship between energy and matter to investigate phenomena of how energy powers the cycling of Earth materials. They begin with this lesson on modeling the Earth processes that form different kinds of rock. This page provides an overview of this lesson.  ](https://www.knowatom.com/science-phenomena-videos/7th-grade-science/the-rock-cycle) [ VIEW LESSON ](https://www.knowatom.com/science-phenomena-videos/7th-grade-science/the-rock-cycle) [![](https://www.knowatom.com/hubfs/Grade/Screenshot%20(32).png) ](https://www.knowatom.com/science-phenomena-videos/7th-grade-science/renewable-energy) ## [Renewable Energy In this unit, students explore the natural processes that cause Earth’s surface to change over time, analyzing how energy causes Earth’s matter to transform and cycle from one form to another. In this lesson, they trace phenomena of how energy is transferred in chemical reactions, which allows scientists to produce ethanol to use as an alternative energy source. This page showcases each component of this lesson.](https://www.knowatom.com/science-phenomena-videos/7th-grade-science/renewable-energy) [ VIEW LESSON ](https://www.knowatom.com/science-phenomena-videos/7th-grade-science/renewable-energy) [![](https://www.knowatom.com/hubfs/image4-Oct-09-2023-06-17-26-8016-AM.png) ](https://www.knowatom.com/science-phenomena-videos/8th-grade-science/chemical-reactions) ## [Chemical Reactions In this unit, students explore the relationship between matter and energy using the phenomenon of material properties to discover why certain materials are useful for a particular function. For this lesson, they focus on the role of energy in changing matter during a chemical reaction phenomena between two substances. This page is a high-level extract of this lesson. ](https://www.knowatom.com/science-phenomena-videos/8th-grade-science/chemical-reactions) [ VIEW LESSON ](https://www.knowatom.com/science-phenomena-videos/8th-grade-science/chemical-reactions) [![](https://www.knowatom.com/hubfs/image4-Oct-08-2023-07-36-35-4598-PM.png) ](https://www.knowatom.com/science-phenomena-videos/6th-grade-science/molecules) ## [Molecules In this unit, students explore the science phenomena of interactions between energy and matter, analyzing how matter can only change when enough energy is present. In this lesson, they investigate the structure of molecules, relating this structure to the matter’s properties. This page is a high-level extract of this lesson.](https://www.knowatom.com/science-phenomena-videos/6th-grade-science/molecules) [ VIEW LESSON ](https://www.knowatom.com/science-phenomena-videos/6th-grade-science/molecules) Standards citation: NGSS Lead States. 2013. *Next Generation Science Standards: For States, By State*s. Washington, DC: The National Academies Press. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it. ![KnowAtom Logo](https://www.knowatom.com/hubfs/KnowAtom%20Logo.svg "KnowAtom Logo") Quick Links Resources Sign Up for Our Blog ### Sign Up for Our Blog Connect with Us - - - - © 2026 KnowAtom LLC  •  10 Brady Drive Unit 3   •  Ipswich MA •   01938 USA [DO NOT SELL MY PERSONAL INFORMATION](https://www.knowatom.com/do-not-sell-my-personal-information) | [Privacy Policy](https://www.knowatom.com/privacy-policy) | [Terms of Use](https://www.knowatom.com/terms-of-use) ```json { "@context" : "http://schema.org", "@type" : "Organization", "address" : { "@type" : "PostalAddress", "addressCountry" : "USA", "addressLocality" : "Salem", "addressRegion" : "MA", "postalCode" : "01970", "streetAddress" : "27 Congress Suite 410" }, "alternateName" : "KA", "areaServed" : { "@type" : "GeoCircle", "geoMidpoint" : { "@type" : "GeoCoordinates", "latitude" : "+42.5182274", "longitude" : "-70.8877569" }, "geoRadius" : "150 km" }, "description" : "Next Generation Science STEM Curriculum", "email" : "fvigeant@knowatom.com", "image" : "https://www.knowatom.com/hubfs/KA-GSD.png", "logo" : "https://www.knowatom.com/hubfs/Knowatom-2017/Image/logo-1.png", "mainEntityOfPage" : { "@id" : "https://www.knowatom.com/7-ms-ps1-5", "@type" : "WebPage", "description" : "7-MS-PS1-5 Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved." }, "name" : "KnowAtom", "sameAs" : [ "https://www.facebook.com/KnowAtom", "https://twitter.com/KnowAtom", "https://www.youtube.com/channel/UCS0rbN0RfqaU1xaISrdVpTA", "https://plus.google.com/110709105138117096940" ], "telephone" : "(617) 475-3475", "url" : "https://www.knowatom.com" } ```