Learning Resource Type

Classroom Resource

Density: Sink and Float for Solids

Subject Area

Science

Grade(s)

8

Overview

In this lesson, students will investigate a wax candle and a piece of clay to understand why the candle floats and the clay sinks even though the candle is heavier than the piece of clay. Students will discover that it is not the weight of the object, but its density compared to the density of water, that determines whether an object will sink or float in water.

Students will be able to determine whether an object will sink or float by comparing its density to the density of water.

    Science (2015) Grade(s): 8

    SC15.8.5

    Observe and analyze characteristic properties of substances (e.g., odor, density, solubility, flammability, melting point, boiling point) before and after the substances combine to determine if a chemical reaction has occurred.

    Unpacked Content

    UP:SC15.8.5

    Vocabulary

    • Characteristic properties (e.g., odor, density, solubility, flammability, melting point, boiling point)
    • Substances
    • Chemical reaction

    Knowledge

    Students know:
    • Each pure substance has characteristic physical and chemical properties that can be used to identify it.
    • Characteristic properties of substances may include odor, density, solubility, flammability, melting point, and boiling point.
    • Chemical reactions change characteristic properties of substances.
    • 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.

    Skills

    Students are able to:
    • Observe characteristic physical and chemical properties of pure substances before and after they interact.
    • Analyze characteristic physical and chemical properties of pure substances before and after they interact.
    • Analyze the properties to identify patterns (i.e., similarities and differences), including the changes in physical and chemical properties of each substance before and after the interaction.
    • Use the analysis to determine whether a chemical reaction has occurred.

    Understanding

    Students understand that:
    • Observations and analyses can be used to determine whether a chemical reaction has occurred.
    • The change in properties of substances is related to the rearrangement of atoms in the reactants and products in a chemical reaction (e.g., when a reaction has occurred, atoms from the substances present before the interaction must have been rearranged into new configurations, resulting in the properties of new substances).

    Scientific and Engineering Practices

    Analyzing and Interpreting Data

    Crosscutting Concepts

    Patterns
    Link to Resource

    CR Resource Type

    Lesson/Unit Plan

    Resource Provider

    American Chemical Society
    Accessibility

    Accessibility

    Video resources: includes closed captioning or subtitles
    License

    License Type

    Custom
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