Polymers are an important ingredient in many materials, including the colorful plastics shown here. Scientists have developed a new polymer material to help repair small cracks that might develop in such polymer-based products.

When water droplets bead up on a surface, it’s because that surface has features that repel the water. The water doesn’t penetrate the surface or flatten out across it like a pool. This concept is key to a new energy technology.

Tarzan, shown here, travels over crop fields with an energy-efficient swinging motion. One day, such robots might help with farm work.

Using new technologies, researchers have 3-D printed a flower whose petals curl when immersed in water. This shows how 3-D printing can be used to print 4-D objects.