Visualize a strategy for approximating the square roots of nonperfect squares through modeling. This video focuses on a ratio, the number of extra tiles over the number of tiles for the next square that will give you a fractional approximation of the square root of a number. This video was submitted through the Innovation Math Challenge, a contest open to professional and nonprofessional producers. This resource is part of the Math at the Core: Middle School collection.

This video segment adapted from Pennsylvania College of Technology and WVIA examines nanotechnology, the art and science of manipulating and rearranging individual atoms and molecules to create useful materials, devices, and systems. Learn how atoms are at the core of nanotechnology and how researchers are working to understand both the structure and behavior of atoms in order to develop revolutionary new products and applications in medicine and beyond. The video also expresses some of the safety concerns related to nanotechnology.

Measuring and dispensing small volumes of a variety of liquids is a critical part of many biology and chemistry laboratory procedures. The smaller the volumes, the more difficult this is, and the more important it is to do so accurately and precisely. Micropipettes are sophisticated instruments designed specifically to measure and dispense small volumes. This video, adapted from the University of Leicester, describes the basic function of a variety of micropipettes. It also demonstrates their proper use and the errors that can result if proper techniques and procedures aren’t followed. This resource is part of the Biotechnology collection.

The technique illustrated in this animation produced by WGBH and Digizyme, Inc., shows how scientists use natural processes and technological innovations to insert genes into loops of DNA called plasmids. Plasmids can then be introduced into bacterial or other cells, which will proceed to replicate the inserted genes or induce the cells to produce such valuable proteins as human insulin and growth hormone. This resource is part of the Biotechnology collection.

In this animation produced by WGBH and Digizyme, Inc., learn about *bacterial transformation*, the process by which DNA plasmids are introduced into a bacterial cell's genome. The animation presents the physical challenges of getting the plasmids through the cell's plasma membrane and the "heat shock" technique used to overcome them. It also shows how researchers test for successful transformations using experimental and negative control plates. This resource is part of the Biotechnology collection.

Use your spatial reasoning skills to calculate the surface area when given a 3D figure. This video focuses on a right rectangular prism and shows you how unit blocks can help you visualize, then calculate the surface area. This video was submitted through the Innovation Math Challenge, a contest open to professional and nonprofessional producers. This resource is part of the Math at the Core: Middle School collection.

Discover how math is required for quality construction when a Master Carpenter shares his experience and expertise. This video focuses on explaining slope as rise over run and shows how slope comes into play when building homes to take math out of the classroom and into real world problem solving. This resource is part of the Math at the Core: Middle School collection.

Solve a linear equation that has negative numbers and a variable. This video focuses on using inverse operations to solve for a variable.

This video was submitted through the Innovation Math Challenge, a contest open to professional and nonprofessional producers and is part of the Math at the Core: Middle School collection.

Experiment with random sampling methodology using goldfish crackers. This video focuses on making inferences based on a set of data, finding averages, and using a ratio table to demonstrate statistical procedures used by scientists when estimating populations in the real world. This video was submitted through the Innovation Math Challenge, a contest open to professional and nonprofessional producers. This resource is part of the Math at the Core: Middle School Collection.

Explore division by modeling problems and grouping with manipulatives. This video focuses on dividing whole numbers by unit fractions and modeling the problems with unit blocks. This video was submitted through the Innovation Math Challenge, a contest open to professional and nonprofessional producers. This resource is part of the Math at the Core: Middle School collection.