A+ Click is an interactive collection of more than 3700 math problems and answers for K-1 K-12 school program. It defines the personal level of math knowledge. You move up into the next level if you give 5 correct answers in a row. Practice makes perfect.

Do you need proof that driving is a dangerous activity? More Americans have died in car crashes over the past 100 years than in all the wars the U.S. has ever fought combined. More than 40,000 Americans die each year on the nation's highways, most as the result of high-speed collisions. In this video segment adapted from NOVA, learn how engineers developed the air bag, an important automobile-safety device now found in most cars.
Recommended for: Grades 3-12

This video segment adapted from Building Big illustrates the strength of the arch in bridge design and construction.

Students explore the interface between architecture and engineering. In the associated hands-on activity, students act as both architects and engineers by designing and building a small parking garage.

The engineering design process involves many steps. Not only must an engineer be able to devise a solution to a problem, he or she must also be ready to test and evaluate that solution to reach the best result. To successfully complete the design process, an engineer must be able to identify design flaws and learn from his or her mistakes. In this video segment adapted from ZOOM, learn about the design process as cast members create automatic door openers that enable them to open their bedroom doors while lying on their beds. For grades 3-8.

In this video adapted from NASA, two members of a NASA research team working to produce carbon nanotubes share some background behind this new technology, show examples of how it will be useful, and explain the various tests being performed to ensure readiness for spaceflight.

A new instructional model, called Argument-Driven Inquiry (ADI), is introduced to elementary teachers in this article. The author shows how school librarians and classroom teachers can collaborate to help students construct and communicate evidence, or arguments. Evidence buckets, a collaborative activity, and related online resources are presented. The article appears in the free online magazine Beyond Weather and the Water Cycle, which is structured around the seven essential principles of climate literacy.

Construct and measure the energy efficiency and solar heat gain of a cardboard model house. Use a light bulb heater to imitate a real furnace and a temperature sensor to monitor and regulate the internal temperature of the house. Use a bright bulb in a gooseneck lamp to model sunlight at different times of the year, and test the effectiveness of windows for passive solar heating.

In this video segment from PEEP and the Big Wide World, children make a dam with dirt, sticks, and stones to try to stop the flow of water.

Earthquakes happen when forces in the Earth cause violent shaking of the ground. Earthquakes can be very destructive to buildings and other man-made structures. Design and build various types of buildings, then test your buildings for earthquake resistance using a shake table and a force sensor that measures how hard a force pushes or pulls your building.

How do you build a tunnel 32 miles long -- under water? This video segment adapted from Building Big, follows the construction of the Channel Tunnel (nicknamed "Chunnel"), the engineering wonder that connects England to France.

In this activity, learners burn a peanut, which produces a flame that can be used to boil away water and count the calories contained in the peanut. Learners use a formula to calculate the calories in a peanut and then differentiate between food calories and physicist calories as well as calories and joules.

This video excerpt from NOVA’s Making Stuff: Cleaner and accompanying demonstration introduce students to the production and importance of bioplastics, or plastics made from plant or animal products.

Watch the ZOOM cast find out how many balloons filled with air and then with water are required to support the weight of a cast member.

In this video segment, members of the ZOOM cast experiment by bending and folding sheets of paper into various shapes to see which shape will support the weight of a heavy book.

In this video segment from ZOOM, Hillary, from Randolph, MA, takes us on a tour of the columns in her neighborhood.

This article describes six collaborative and real data projects that engage elementary students in collecting and sharing local data and communicating with students across the country and world.

Students analyze video clips of kids rolling down a hill on skates, scooters, and bikes to determine whether mechanical energy is conserved.

In this video segment adapted from ZOOM, cast members design and build door alarms using a variety of materials, including aluminum foil, batteries, and buzzers.

In this video segment adapted from ZOOM, cast members discover that metal is a good conductor of electricity as they play the steadiness tester game.