Students quantify the percent of light reflected from solutions containing varying concentrations of red dye using LEGO© MINDSTORMS© NXT bricks and light sensors. They begin by analyzing a set of standard solutions with known concentrations of food coloring, and plot data to graphically determine the relationship between percent reflected light and dye concentration. Then they identify dye concentrations for two unknown solution samples based on how much light they reflect. Students gain an understanding of light scattering applications and how to determine properties of unknown samples based on a set of standard samples.

This resource is part of Tools4NCTeachers.

In this lesson, students will identify the number of objects in a group as greater than, less than, or equal to the number of objects in another group, for numbers 1-5. Students will understand the relationship between number labels (such as "4" naming a collection of four) and quantities. They will understand that counting by ones increases the quantity by one more.

This resource is from Tools4NCTeachers.In second grade, students learn to add and subtraction using strategies based on place value and number relationships.  They use a variety of representations such as base ten drawings and number lines.  Second graders do not learn the standard algorithm.  This resource outlines second grade addition and subtraction strategies