This course  was created by the Rethink Education Content Development Team. This course is aligned to the NC Standards for 4th Grade Math. 

An interactive applet and associated web page that demonstrate a right angle (those equal to 90 deg). The applet presents an angle (initially 90 deg) that the user can adjust by dragging the end points of the line segments forming the angle. As it changes it shows the angle measure and a message that indicate which type of angle it is. There a software 'detents' that make it easy capture exact angles such as 90 degrees and 180 degrees The message and angle measures can be turned off to facilitate classroom discussion. The text on the page has links to other pages defining each angle type in depth. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Students are introduced to the sound environment as an important aspect of a room or building. Several examples of acoustical engineering design for varied environments are presented. Students learn the connections between the science of sound waves and engineering design for sound environments.

Student groups rotate through four stations to examine light energy behavior: refraction, magnification, prisms and polarization. They see how a beam of light is refracted (bent) through various transparent mediums. While learning how a magnifying glass works, students see how the orientation of an image changes with the distance of the lens from its focal point. They also discover how a prism works by refracting light and making rainbows. And, students investigate the polar nature of light using sunglasses and polarized light film.

In this lesson students learn to classify quadrilaterals, including trapezoids, with a focus on different types of parallelograms. They learn the relationships among rectangles, squares, and rhombuses as different types of parallelograms.

This short video and interactive assessment activity is designed to teach second graders about visually evaluating parallel lines cut by a traversal.

Students will explore straight, right, acute and obtuse angles. Students will go to the playground to search for angles. The students will use digital cameras to record their findings. They will use their findings to create a Power Point to present to the class.