3. Student Learning Map

  • Topic:06- Physical Properties and Changes
  • Subject(s):Science
  • Days:22
  • Grade(s):8
Key Learning:

Physical properties are used to observe and describe matter. Matter can undergo physical changes and these changes will not alter the basic nature of the substance.

Unit Essential Question(s):
 
 

How do we use physical properties and changes to describe the nature of a substance?

   
Concept:

Classifying Matter

LEQ: Number 1

  • Use a concept map or another visual aid to discuss how matter is classified into either pure substances or mixtures.
  • Emphasize the key difference is the uniformity of composition. The composition of a pure substance is constant. The composition of a mixture can vary widely because the composition of a mixture is not fixed.
  • Elements and compounds will be discussed further in unit 6.
  • Discuss how mixtures are substances held together by physical forces.
  • Discuss the two types of mixtures- homogeneous or heterogeneous. Discuss how based on the size of its largest particle, a mixture can be classified as a solution, a suspension or a colloid.
  • Discuss how solutions are homogeneous. Emphasize that if you mix things up and they stay in even distribution, it is a solution.
  • Provide the opportunity for students to create and experience the differences between mixtures and solutions. For example, sugar in water (solution) versus sand in water (mixture).
  • Discuss the two common methods for separating mixtures; filtration and distillation.
  • Address the misconception that all of the particles in mixtures and solutions are similar in size. If this were true, mixtures could not be separated by fitration.
  • LEQ: Number 2

  • Introduce solubility as a physical property and discuss how solubility is dependent on pressure and temperature.
  • Discuss the the relationship between solute, solvent and a solution. The solute is the substance that is dissolved. The solvent is the substance in which the solute dissolves. The resulting substance is called a solution.
  • Describe other physical properties and the important roles they play.
  • LEQ: Number 3

  • HOTS: Classifying/Categorizing or Error Analysis could be used to demonstrate the ET LEQ.
  • Concept:

    Measuring Matter

    LEQ: Number 1

  • Discuss how scientists describe objects by their properties. Emphasize that properties pertain to a single object while interactions need two or more objects.
  • Discuss how people use their senses to determine the basic properties of an object. Provide the opportunity for students to explore descriptions using their senses.
  • Discuss how measuring instruments such as a ruler; extend and refine your senses. Discuss the standard unit of length- meter (m).
  • Provide students with the opportunity to measure the length of several objects. Students should be able to differentiate between centimeters, meters and kilometers. Discuss the unit kilometer and provide examples of things measured in kilometers.
  • Discuss how one way to measure the amount of material is to measure the volume of an object.
  • Emphasize that for regular solids like cubes, rectangles, cones, spheres and cylinders, there are mathematical equations for calculating volume volume.
  • Emphasize that one cubic centimeter is used when recording the volume of a solid.
  • Discuss how to determine the volume of a liquid using a graduated cylinder. Discuss the term meniscus and the standard unit of measure- liter (L).
  • Provide the opportunity for students to determine the volume of a variety of liquids using different graduated cylinders. Students should be able to differentiate between milliliters and liters.
  • Note the trends on the on the periodic table.
  • LEQ: Number 2

  • HOTS: Classifying/Categorizing or Error Analysis could be used to demonstrate the ET LEQ.
  • Concept:

    Mass versus Weight

    LEQ: Number 1

  • Discuss how another way to measure the amount of material is to measure the mass of an object.
  • Emphasize that the more mass an object has, the more matter it has and the heavier it is.
  • Provide the opportunity for students to use triple beam balances to determine the mass of a variety of objects. Students should focus on reporting measurements in grams. Discuss the terms milligram and kilogram.
  • Discuss whether gas has mass. Address the misconception that air does not have mass. Discuss ideas for determining the mass of a gas such as measuring the mass of a ball before and after it is filled with air. Use an electronic balance or visual aid during your discussion.
  • Discuss the differences and similarities between mass and weight.
  • Describe the role that gravity plays in weight.
  • Explain how the size of an object affects the amount of gravity that it is capable of exerting and how this can affect the weight of an object.
  • Discuss how gravity is a force that attracts all physical objects towards each other. The greater the mass of an object, the stronger the force of gravity. Discuss how because of its smaller size, the Moon's gravity is one-sixth of the Earth's gravity.
  • LEQ: Number 2

  • HOTS: Constructing Support, Deductive Reasoning or Error Analysis could be used to demonstrate the ET LEQ.
  • Concept:

    Density

    LEQ: Number 1

  • Introduce density as a physical property.
  • Discuss how scientists use the relationship between mass and volume to define a property that can help you decide what kind of material an object is made of.
  • Discuss how the density of an object can be explained by the arragnement and weight of its particles.
  • Determine the density of different objects by finding the mass and volume of the object. Use the folllowing equation: density= mass/volume.
  • Practice solving for mass or volume (rearrange equation) using a table of densities. Do not have student memorize the three different equations. Discuss the relationships between mass, volume and density using the term independ and depend variable.
  • Remind students of the how to use the water displacement method to determine the density of an irregularly shaped solid.
  • Discuss the density of water and the ability of an object to float or sink in water based on its density.
  • Discuss the difference between density and buoyancy (pg. 458).
  • LEQ: Number 2

  • HOTS: Constructing Support, Inductive Reasoning, Deductive Reasoning or Error Analysis could be used to demonstrate the ET LEQ.
  • Concept:

    Exploring Additional Physical Properties

    LEQ: Number 1

  • Discuss the following idea: the more properties we can identify for a substance, the better we know the nature of that substance. These properties can then help us model the substance and thus understand how this substance will behave under various conditions.
  • Re-identify solubility and density as two types of physical properties.
  • Discuss the other various types of physical properties including magnetic properties, boiling and melting points, and thermal and electrical conductivity.
  • Classify and compare different substances based on the physical properites listed above.
  • Emphasize that physical properties are independent of the size of the sample.
  • LEQ: Number 2

  • HOTS: Classifying/Categorizing or Error Analysis could be used to demonstrate the ET LEQ.
  • Concept:

    Physical Changes

    LEQ: Number 1

  • Explain that physical changes are about energy and states of matter. Explain that anytime a substance freezes, boils, evaporates, or condenses a physical change occurs.
  • Emphasize that a physical change occurs when some of the properties of a material change, but the substances in the material remain the same.
  • Physical changes can be caused with forces like motion, temperature and pressure.
  • Discuss the law of conservation of mass in relation to physical changes.
  • LEQ: Number 2: Constructing Support or Deductive Reasoning can be used to demonstrate the ET LEQ.

    Additional Information:

    The asterisk (*) next to the vocabulary terms above indicates essential FCAT vocabulary.

    Suggested Resources-

    Classifiying Matter: See Classifying Matter Graphic Organizer 

    Glencoe Physical Science program, labs: textbook, teacher created and student conducted, laboratory write-up template, basic lab apparatus, Internet and Unitedstreaming.

    Vocabulary Report

    • *mixture -

      The product of two or more substances mixed together but not chemically combines. Mixtures can be separated through physical means such as filtering, freezing, melting, or distilling.

    • *condensation -

      The change of a gas or vapor to a liquid, either by cooling or by being subjected to increased pressure.

    • physical property -

      Any characteristic of a material, such as size or shape, that you can observe or attempt to observe without changing the identity of the material.

    • *density -

      Concentration of matter of an object; the mass per unit volume of a substance in a given area.

    • *mass -

      Amount of matter in an object.

    • property -

      Description of how the object interacts with another object.

    • length -

      A measure of distance.

    • *evaporation -

      The change of a liquid into a vapor at a temperature below the boiling point.

    • *solution -

      A mixture of two or more substances uniformly dispersed throughout a single phase.

    • boiling point -

      The temperature at which the pressure of the vapor in the liquid is equal to the external pressure acting on the surface of the liquid.

    • buoyancy -

      Ability of a fluid-a liquid or a gas-to exert an upward force on an object immersed in the fluid.

    • weight -

      Gravitational force exerted on an object.

    • *solubility -

      A measure of the ability of a substance to dissolve in another substance.

    • melting point -

      Temperature at which a solid begins to liquefy.

    • *Law of Conservation of Mass -

      States that the mass of all substances present before a chemical change equals the mass of all the substances remaining after the change.

    • *volume -

      A measurement of how much space something occupies.

    • filtration -

      A process that separates materials based on the size of their particles.

    • *physical change -

      Any change in size, shape, or state of matter in which the identity of the substance remains the same.

    • conductivity -

      Property of metals and alloys that allows heat or electrical charges to pass through the material easily.

    • distillation -

      Process than can separate two substances in a mixture by evaporating a liquid and recondensing its vapor.

    • *magnetic -

      Having the property of attracting iron and certain other materials by virtue of a surrounding field of force.