After explaining the difference between cleavage and fracture, this resource discusses various types of cleavage and their importance in identifying minerals.

Streak is the color of the powder of a mineral. This page discusses the importance of streak when identifying minerals.

Visit an example-rich exploration of poster art and learn how famous faces have been used to convey meanings and messages across the decades. An excellent resource for discovering how art can be a window into a particular time, Ballyhoo! looks at images from a range of periods in U.S. history, including turn-of-the century America (ca. 1890), World War I, World War II, and the 1960s. An effective device, also, for learning about celebrity culture and the tried-and-true advertising ruse of celebrity endorsement.

Over the course of many years, humans evolved to abandon foraging and took up farming for their food needs. Scientists are still not sure why humans abandoned foraging and took up farming in several places around the world at about the same time. This gallery highlights where agriculture emerged and what was grown.

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Getting Started

Type of Unit: Introduction

Prior Knowledge

Students should be able to:

Solve and write numerical equations for whole number addition, subtraction, multiplication, and division problems.
Use parentheses to evaluate numerical expressions.
Identify and use the properties of operations.

Lesson Flow

In this unit, students are introduced to the rituals and routines that build a successful classroom math community and they are introduced to the basic features of the digital course that they will use throughout the year.

An introductory card sort activity matches students with their partner for the week. Then over the course of the week, students learn about the lesson routines: Opening, Work Time, Ways of Thinking, Apply the Learning, Summary of the Math, and Reflection. Students learn how to present their work to the class, the importance of taking responsibility for their own learning, and how to effectively participate in the classroom math community.

Students then work on Gallery problems to further explore the program’s technology resources and tools and learn how to organize their work.

The mathematical work of the unit focuses on numerical expressions, including card sort activities in which students identify equivalent expressions and match an expression card to a word card that describes its meaning. Students use the properties of operations to identify equivalent expressions and to find unknown values in equations.

Students review the ways classroom habits and routines can strengthen their mathematical character. Students learn what a Gallery is and how to choose a Gallery problem to work on. They then choose one of three Gallery problems that introduce the unit’s technology resources. The three Gallery problems combine working with expressions with the resources available with this unit.Key ConceptsUnderstand that a Gallery gives students a choice of several problems. Understand what to consider when choosing a problem. Know how to work on a Gallery problem and how to present work on gallery problems.Goals and Learning ObjectivesKnow how to choose a problem from a Gallery.

This multimedia site offers readings of Whitman's poetry, an introduction, a gallery of images and works through the years of his career, and a reflection of Whitman's significance.

The National Portrait Gallery of the Smithsonian Institution provides an online exhibit of portrait photographer Philippe Halsman who photographed famous people from Presidents to entertainers.

A thorough examination of the life of Theodore Roosevelt and the people and events that influenced him. You'll find photographs of Roosevelt, as well as photos, paintings, and biographies of some influential people in Roosevelt's life.