Classroom Resource

Density: Sink and Float for Liquids

Subject Area

Science

Grade(s)

8

Overview

In this lesson, students will observe three household liquids stacked on each other and conclude that their densities must be different. They will predict the relative densities of the liquids and then measure their volume and mass to see if their calculations match their observations and predictions.

Students will be able to determine whether a liquid will sink or float in water 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
https://www.middleschoolchemistry.com/lessonplans/chapter3/lesson5

CR Resource Type

Lesson/Unit Plan

Resource Provider

American Chemical Society
Accessibility

Accessibility

Video resources: includes closed captioning or subtitles
License

License Type

Custom

Custom License Type (URL)

https://www.acs.org/content/acs/en/terms.html

Comments or Notes

A video that explains how to teach the lesson is provided.

Approved Date

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