Science - 2018-19

PS.5 - Changes in Matter

The student will investigate and understand changes in matter and the relationship of these changes to the Law of Conservation of Matter and Energy. Key concepts include

a) physical changes;

b) chemical changes; and

c) nuclear reactions. 

Bloom's Levels:  Analyze; Understand

Adopted: 2010


  • Matter can undergo a variety of changes, both physical and chemical.
  • Changes in matter are accompanied by changes in energy.

  • I can explain why my car can be repaired after an accident, but not if it caught fire.
  • I can create new compounds.
  • I can explain and choose an energy source for my neighborhood.


  • Matter can undergo physical and chemical changes. In physical changes, the chemical composition of the substances does not change. In chemical changes, different substances are formed. Chemical changes are often affected by the surface area/volume ratio of the materials involved in the change.
  • The Law of Conservation of Matter (Mass) states that regardless of how substances within a closed system are changed, the total mass remains the same. The Law of Conservation of Energy states that energy cannot be created or destroyed but only changed from one form to another.
  • A chemical equation represents the changes that take place in a chemical reaction. The chemical formulas of the reactants are written on the left, an arrow indicates a change to new substances, and the chemical formulas of the products are written on the right. Chemical reactions are classified into two broad types: ones in which energy is released (exothermic) and ones in which energy is absorbed (endothermic). (The study of synthesis, decomposition, and replacement reactions can be reserved for high school chemistry.) 
  • Another type of change occurs in nuclear reactions. Nuclear energy is the energy stored in the nucleus of an atom. This energy can be released by joining nuclei together (fusion) or by splitting nuclei (fission), resulting in the conversion of minute amounts of matter into energy. In nuclear reactions, a small amount of matter produces a large amount of energy. However, there are potential negative effects of using nuclear energy, including radioactive nuclear waste storage and disposal.


In order to meet this standard, it is expected that students will

b)  identify the reactants and products in a given chemical equation formula.

     given chemical formulas, write and balance simple chemical equations.

     analyze experimental data to determine whether it supports the Law of Conservation of  Mass.

     recognize that some types of chemical reactions require continuous input of energy (endothermic) and others release energy (exothermic).

c)  describe, in simple terms, the processes that release nuclear energy (i.e., nuclear fission and nuclear fusion). Create a simple diagram to summarize and compare and contrast these two types of nuclear energy.

     evaluate the positive and negative effects of using nuclear energy.

a-c)  compare and contrast physical, chemical, and nuclear changes.

design an investigation that illustrates physical and chemical changes.


physical change, chemical change, reactants, nuclear charges, fusion, Law of Conservation of Matter (mass), fission, Law of Conservation of Energy, endothermic energy, exothermic energy, chemical equation

Updated: Jun 29, 2018