Standard #: SC.8.P.9.1


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Explore the Law of Conservation of Mass by demonstrating and concluding that mass is conserved when substances undergo physical and chemical changes.


General Information

Subject Area: Science
Grade: 8
Body of Knowledge: Physical Science
Big Idea: Changes in Matter - A. Matter can undergo a variety of changes.

B. When matter is changed physically, generally no changes occur in the structure of the atoms or molecules composing the matter.

C. When matter changes chemically, a rearrangement of bonds between the atoms occurs. This results in new substances with new properties.

Clarification for grades K-5: The target understanding for students in the elementary grades should focus on Big Ideas A and B.

Clarification for Grades 6-8: The target understanding for students in the middle grades should begin to transition the focus to: C. When matter changes chemically, a rearrangement of bonds between the atoms occurs. This results in new substances with new properties.

Date Adopted or Revised: 02/08
Content Complexity Rating: Level 3: Strategic Thinking & Complex Reasoning - More Information
Date of Last Rating: 05/08
Status: State Board Approved
Assessed: Yes

Related Courses

Course Number1111 Course Title222
2002100: M/J Comprehensive Science 3 (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
2002110: M/J Comprehensive Science 3, Advanced (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
2003010: M/J Physical Science (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
2003020: M/J Physical Science, Advanced (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
7820017: Access M/J Comprehensive Science 3 (Specifically in versions: 2014 - 2015, 2015 - 2018, 2018 - 2023, 2023 and beyond (current))
2002085: M/J Comprehensive Science 2 Accelerated Honors (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
2001105: M/J Coastal Science 2 (Specifically in versions: 2022 - 2024, 2024 and beyond (current))


Related Access Points

Access Point Number Access Point Title
SC.8.P.9.In.1 Observe and classify changes in matter as physical (reversible) or chemical (irreversible).
SC.8.P.9.Su.1 Observe and recognize physical changes in matter as able to change back (reversible), such as water to ice, and chemical changes of matter as unable to change back (irreversible), such as cake to cake batter.
SC.8.P.9.Pa.1 Recognize an example of a physical change, such as ice changing to water.
SC.8.P.9.Pa.2 Recognize that heat influences changes (chemical) in matter, such as cooking.


Related Resources

Learning Goal

Name Description
Colorful Electrolysis

Electrolysis is the decomposition of a solution by using a electrical current. Chemical changes occur during this process. The electrodes act a conductors where electron transfer take place. The flow of electrons are from the anode (positive electrode-the site of oxidation), to the cathode (negative electrode - site of reduction). Students will explore chemical changes by observing the Electrolysis of potassium iodide, copper (II) bromide, and sodium chloride solutions. Students will use their observations to identify the products formed at the anode and the cathode in the electrolysis of each solution.

Lesson Plans

Name Description
Maintaining Mass

The student will demonstrate that mass is conserved when substances undergo chemical and/or physical changes through experimentation and evaluation of experimentation procedures. Students will be able to analyze the demonstration and provide evidence for or against the law of conservation of mass.Students will first view and then hypothesize, based on their knowledge of the law of conservation of mass, why a teacher demonstration does not seem to prove the law. Students will then explore a modified version of the experiment to determine ways that the teacher demonstration should have been changed to show conservation of mass effectively.

The Mystery of Mass

This lesson is a set of two activities:

  1. The conservation of mass is illustrated during a teacher demonstration of dissolving salt into water. The mass of the system will be calculated before and after the substances are combined so that students can compare them. Students investigate whether mass stays the same, increases, or decreases during the physical change.

  2. Students complete a paper atom and molecule activity showing the connection between a proper balanced equation and the conservation of mass. Students will use paper atom manipulatives to show the relationships between the reactants and products of a chemical reaction. The balancing of a chemical reaction is the conservation of mass in action.
The Nerve to Conserve

While not explicitly stated in the standard, the idea that the Law of Conservation of Mass is conditional to a closed system and this is the focus of my lesson. This lesson starts with an investigation of seeds growing in a jar with students quickly recording the mass each day for 5 days. On the 5th day, students complete 2 more investigations, half with closed systems and half with open systems. They will compare the final masses and draw conclusions independently and through class discussions about the condition of the Law of Conservation of Mass.

Matter Changes but Mass is Saved!

The focus of this lesson is for students to gain an understanding of how to identify if changes in matter are a physical or chemical change. Also, students will see that the mass before and after a physical and chemical changes will be the same which supports the Law of Conservation of Mass. The lesson consists of teacher demonstrations, student lab activities. a writing activity to support student findings and the creation of presentations for students to share their results and applications of concepts to the real world.

Change or Not - Same Mass

The students make observations and take the mass of various structures constructed by the teacher. They rearrange the structures and measure the mass again. During the whole class discussion the students come to understand that during a chemical or physical change the mass is conserved.

Law of Conservation of Mass

In this lesson, students will learn the difference between physical and chemical changes and their relationship to the Law of Conservation of Mass. The major concept that students should learn is that mass is conserved when substances undergo a physical or chemical change (Law of Conservation of Mass).

Balancing Chemical Equations Using a Visual Aid

Students will use this kinesthetic activity to further their knowledge regarding balancing chemical equations.

Conservation of mass lab This activity may also be used as a demonstration lab, if materials aren't available, time, or other problems exist.
Conserve the Mass Students work through different activities examining the changes of physical and chemical and how mass is conserved.
Iced

The students will demonstrate understanding of the Laws of Conservation of Mass by drawing conclusions based on their observations.

Lord of Fries Conservation MEA

In this Model-Eliciting Acivity (MEA), students will investigate different types of hamburger patties and choose the one that is best for the restaurant. Some of the areas that students will examine is how the hamburger patties undergo a chemical change, but mass is not lost only changed into different substances. They will also investigate how the hamburger patties are chemically changed due to a change in temperature. Students will also be exposed to how the Law of Conservation of Mass is used in our daily lives. For example, cooking a hamburger patty, the mass is not lost but sometimes the juices are separated from the meat. Also, in French fries, matter is not created but cooking oil is absorbed by the fries.

Model Eliciting Activities, MEAs, are open-ended, interdisciplinary problem-solving activities that are meant to reveal students’ thinking about the concepts embedded in realistic situations. MEAs resemble engineering problems and encourage students to create solutions in the form of mathematical and scientific models. Students work in teams to apply their knowledge of science and mathematics to solve an open-ended problem while considering constraints and tradeoffs. Students integrate their ELA skills into MEAs as they are asked to clearly document their thought processes. MEAs follow a problem-based, student-centered approach to learning, where students are encouraged to grapple with the problem while the teacher acts as a facilitator. To learn more about MEAs visit: https://www.cpalms.org/cpalms/mea.aspx

Tip the Scales, Part One Students will find evidence to support the Law of Conservation of Mass which states that matter is neither created nor destroyed, it only changes form.

Original Student Tutorial

Name Description
Conservation of Mass

Understand and demonstrate that mass is conserved when substances undergo physical and chemical changes in a closed system with this interactive tutorial.

Teaching Idea

Name Description
Recognizing Chemical Reactions This resource describes activity that will allow students to observe the effects of a chemical change as opposed to a physical change. It also gives them the opportunity to observe conservation of matter by modeling chemical equations. The main learning objective is the recognition that all chemical reactions create new molecules and that in a chemical reaction the original atoms get rearranged, bonding together in different ways.

Unit/Lesson Sequence

Name Description
Middle School Chemistry Unit | Chapter 6 | Chemical Change Students explore the concept that chemical reactions involve the breaking of certain bonds between atoms in the reactants, and the rearrangement and rebonding of these atoms to make the products. Students also design tests to investigate how the amount of products and the rate of the reaction can be changed. Students will also explore endothermic and exothermic reactions.

Virtual Manipulative

Name Description
Balancing Chemical Equations

This activity will allow you to practice balancing a chemical equation. You will have to make sure you are following the law of conservation of mass and recognize what can change to balance an equation.
You can:

  • Balance a chemical equation.
  • Recognize that the number of atoms of each element is conserved in a chemical reaction.
  • Describe the difference between coefficients and subscripts in a chemical equation.
  • Translate from symbolic to molecular representation.

Student Resources

Original Student Tutorial

Name Description
Conservation of Mass:

Understand and demonstrate that mass is conserved when substances undergo physical and chemical changes in a closed system with this interactive tutorial.

Virtual Manipulative

Name Description
Balancing Chemical Equations:

This activity will allow you to practice balancing a chemical equation. You will have to make sure you are following the law of conservation of mass and recognize what can change to balance an equation.
You can:

  • Balance a chemical equation.
  • Recognize that the number of atoms of each element is conserved in a chemical reaction.
  • Describe the difference between coefficients and subscripts in a chemical equation.
  • Translate from symbolic to molecular representation.


Parent Resources

Virtual Manipulative

Name Description
Balancing Chemical Equations:

This activity will allow you to practice balancing a chemical equation. You will have to make sure you are following the law of conservation of mass and recognize what can change to balance an equation.
You can:

  • Balance a chemical equation.
  • Recognize that the number of atoms of each element is conserved in a chemical reaction.
  • Describe the difference between coefficients and subscripts in a chemical equation.
  • Translate from symbolic to molecular representation.


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