Bend, Twist and Break: Beyond the Laboratory

Dr. Chris Muhlstein explains that when scientists study fracture surfaces from controlled experiments to understand the resulting shapes and features, they can use their understanding to deduce what happened when they were not around to see the material fail or break. Further they can predict what will have to a larger or smaller piece of material under stress. This process is how scientists and engineers translate a lab experiment into a design for an airplane, bridge or even a bike frame.

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Bend, Twist and Break: Breaking Glass

Dr. Chris Muhlstein explains that researchers learn about the scientific basis for failure of materials by running experiments in the lab, using a simple shape like a glass rod to calculate the strength of material and predict its failure. The same tests can be done at the micro and nano scale using tiny specimens. Students can run a similar experiment with a bar of chocolate.

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Bend, Twist and Break: Fracture Surfaces

Dr. Chris Muhlstein explains that fracture surfaces can reveal how and why a material has failed. An image of a fracture surface has features or shapes that we can use to understand where a material failed and why. Scientists use an optical microscope or a scanning electron microscope to read a fracture surface at high magnifications, much like we read maps to find our way.

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Bend, Twist and Break: The Bridge

Dr. Chris Muhlstein explains that the arrangement of atoms in a material determines the properties. He drops an iPod to illustrate how the arrangement of atoms can protect it from damage; he narrates footage of the collapse of the Tacoma Narrows Bridge in the 1940s to show how the deformation of materials can cause the collapse of a structure.

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Breathing Blue

In this demonstration of chemical change, the presenter blows breath into a methylene blue solution releasing carbon dioxide which acidifies the water and changes it from a bright blue color to green.

Dark Energy

Dark energy makes up 70 percent of the universe. In this video from QUEST produced by KQED, meet one of the country's leading scientists who is trying to understand dark energy.

Density and Buoyancy: Experimenting with Club Soda

In this video segment adapted from ZOOM, the cast discovers that gas-filled bubbles act like life jackets for raisins, making them buoyant.

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Density and Buoyancy: Making Eggs Float

Why does an egg float in salt water? Learn about density and buoyancy in this video segment adapted from ZOOM.

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Density and Buoyancy: Mixing Hot and Cold Water

Watch warm water float on top of cold water in this video segment adapted from ZOOM.

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Density and Buoyancy: Pouring Air into Water

This video segment adapted from ZOOM offers a clever demonstration of buoyancy by showing how to pour a cup of air into a cup filled with water.

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Density and Buoyancy: Testing Liquids

Will a grape float in oil? Will a metal nut sink in corn syrup? Watch as the ZOOM cast tests the buoyancy of a variety of liquids and objects.

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Developing the Periodic Table

This video excerpt from NOVA: "Hunting the Elements" looks at how early chemists developed the periodic table of elements.

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Do Materials Get Tired? Creep

This video explains that materials will deform slowly or “creep” under the right conditions, when constant force is applied. “Strain” is illustrated with rubber bands and we learn that engineers can calculate creep strain as a function of time.

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Do Materials Get Tired? Fatigue

This video explains how the strength of a material can be measured in the laboratory and used to design structures, like bikes, airplanes, and even chairs. We see a controlled lab experiment that applies precise force to a paperclip until it breaks.

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Do Materials Get Tired? Intro

This video explains matter is made up of atoms that dictate the properties of materials. Mechanical engineers measure the stress a material can take until it breaks. Their ultimate goal is to make a material that will repair itself.

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Don't Mess with Mercury

Learn about the dangers of mercury in this short video from the U.S. Environmental Protection Agency.

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Fracture Surfaces of Paperclips

This video features a Penn State University professor, Dr. Chris Muhlstein, who explains that the fracture surface of a paper clip is a map of how it failed, to a trained eye. He invites us to view a variety of surfaces with a virtual microscope.

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Global Warming and The Greenhouse Effect

This video excerpt from Race to Save the Planet discusses the greenhouse effect and global warming.

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Global Warming: Carbon Dioxide and the Greenhouse Effect

This video segment adapted from NOVA/FRONTLINE demonstrates the physical property of carbon dioxide that causes the greenhouse effect.

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Global Warming: The Physics of the Greenhouse Effect

This video segment adapted from NOVA/FRONTLINE examines the greenhouse effect, its role in keeping Earth habitable, and the industrial changes that have led to an increase in the planet's average temperature.

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