Learning Resource Type

Classroom Resource

Surface Tension

Subject Area

Science

Grade(s)

8

Overview

In this lesson, students will observe several phenomena related to the polarity of water molecules. They will observe a demonstration of a paper clip being placed on the surface of the water. Students will place drops of water in an already-filled test tube and on the surface of a penny. They will compare the way water behaves with the less polar liquid isopropyl alcohol and will see how detergent affects water’s surface tension. Students will relate these observations to an explanation of surface tension at the molecular level.

Students will be able to explain, on the molecular level, the effects of polarity on water’s surface tension.

    Science (2015) Grade(s): 8

    SC15.8.2

    Plan and carry out investigations to generate evidence supporting the claim that one pure substance can be distinguished from another based on characteristic properties.

    Unpacked Content

    UP:SC15.8.2

    Vocabulary

    • Investigation
    • Claims
    • Evidence
    • Substance
    • Matter
    • Composition
    • Property
    • Element
    • Compound
    • Pure substance
    • Characteristic properties
    • Physical property (includes, but not limited to, color, odor, density, melting point, boiling point, solubility)
    • Chemical property (includes, but not limited to, flammability, reactivity with water, pH)

    Knowledge

    Students know:
    • A substance is matter which has a specific composition and specific properties.
    • Every pure element is a substance. Every pure compound is a substance.
    • Pure substances have characteristic properties.
    • Characteristic properties are physical or chemical properties that are not affected by the amount or shape of a substance.
    • Characteristic properties can be used to identify a pure substance.
    • Physical properties of a substance are characteristics that can be observed without altering the identity (chemical nature) of the substance.
    • Color, odor, density, melting temperature, boiling temperature, and solubility are examples of physical properties.
    • Chemical properties of a substance are characteristics that can be observed but alter the identity (chemical nature) of the substance.
    • Flammability, reactivity with water, and pH are examples of chemical properties.

    Skills

    Students are able to:
    • Identify the phenomena under investigation, which includes pure substances and their characteristic properties.
    • Identify the purpose of the investigation, which includes demonstrating that one pure substance can be distinguished from another based on characteristic properties.
    • Develop a plan for the investigation individually or collaboratively.
    • Describe factors used in the investigation including appropriate units (if necessary), independent and dependent variables, controls and number of trials for each experimental condition.
    • Perform the investigation as prescribed by the plan.
    • Make a claim, to be supported by evidence, to support or refute an explanation or model for a given phenomenon, including the idea that one pure substance can be distinguished from another based on characteristic properties.
    • Identify evidence to support the claim from the given materials.
    • Evaluate the evidence for its necessity and sufficiency for supporting the claim.
    • Use reasoning to connect the evidence and evaluation to the claim that one pure substance can be distinguished from another based on characteristic properties.

    Understanding

    Students understand that:
    • Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.
    • Pure substances can be distinguished from other pure substances based on characteristic properties.
    • Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.

    Scientific and Engineering Practices

    Planning and Carrying out Investigations

    Crosscutting Concepts

    Patterns
    Link to Resource

    CR Resource Type

    Lesson/Unit Plan

    Resource Provider

    Other

    Resource Provider other

    American Chemical Society
    Accessibility

    Accessibility

    Text Resources: Content is organized under headings and subheadings
    Video resources: includes closed captioning or subtitles
    License

    License Type

    CUSTOM
    ALSDE LOGO