Subtopic: Properties of Matter

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.

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.

Breaking Things on Purpose
*Materials such as metals (aluminum, iron, copper, etc.), ceramics (silicon carbide, porcelain) or polymers (milk jugs made of polyethylene) are tested by scientists and engineers to reveal certain mechanical properties such as the maximum stress a material can withstand. The stress at which a material breaks is a measure of its strength. In this lesson you will be testing the strength of a delicious material you know as chocolate!

Buoyancy Brainteasers: Balloon-in-Car Puzzler
This interactive brainteaser from the NOVA Web site challenges you to explain the behavior of a helium-filled balloon in a moving car.

Buoyancy Brainteasers: Buoyancy Question
This interactive brainteaser from the NOVA Web site challenges you to figure out what causes an object to sink.

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.

Density and Buoyancy: Mixing Hot and Cold Water
Watch warm water float on top of cold water in this video segment adapted from ZOOM.

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.

Disappearing Milk
A magician pours milk into a glass, but when he turns the glass upside down, nothing comes out. How does he do it? Discover the science behind the "magic" in this video adapted from the American Society of Mechanical Engineers.

Dissolving Salts in Water
In this interactive activity adapted from Iowa State University, design and carry out an experiment: dissolve salts in water, see how different ionic compounds produce different reactions, and observe the resulting changes in temperature.

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.

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.

Do Materials Get Tired? How Long will a Paperclip Last? (HS)
This lesson plan investigates how materials fail under prolonged stress. By rotating the angle and type of paperclips, students mimic tests done by engineers who make sure that things will not break due to fatigue while you are using them.

Dust Explosion
In these videos adapted from the Journal of Chemical Education, observe how a material that is usually hard to ignite becomes very flammable when its particles are suspended in air.

Floating and Sinking: Hot Air Balloons
Why do hot air balloons float? This resource from the NOVA Web site offers a series of interactive activities that illustrates the physics of hot air balloons.

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.

Global Warming and The Greenhouse Effect
This video excerpt from Race to Save the Planet discusses the greenhouse effect and global warming.

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.

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.

How Hard is Chocolate?
Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

Lifting with Air
How can you lift a heavy metal table using air? In this video segment adapted from ZOOM, cast members succeed in lifting a table using their own breath and a few plastic bags.

Mechanical Properties of Chocolate: How Hard is your Chocolate?
Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

Mystery Mud: Exploring Changes in States of Matter
Join a group of middle-school students on a visit to a laboratory at the Massachusetts Institute of Technology, where they experiment with "mystery mud" and learn about the relationships between magnetism, particle motion, and changes in the state of matter.

Oil Contaminants Hidden from View
This video adapted from KTOO explores why the beaches of Latouche Island and Knight Island, Alaska, contain remnants of an oil spill and discusses its resulting impact on the Alutiiq community of Chenega Bay.

Penn State University Combustion Lab Tour
In this video, a fuels science professor tours a Combustion Lab where a team is investigating renewable, advanced and clean burning fuels. Overall, the researchers are interested in power, emissions, and performance.

Snapshot of U.S. Energy Use
This video segment adapted from NOVA/FRONTLINE looks at American energy consumption and the resulting production of greenhouse gases.

Stories in the Ice
Take a journey back through time, on the NOVA/FRONTLINE Web site, using ice cores to learn about Earth's climatic history, including evidence of global warming and nuclear activity.

Structure and Property Changes of Water
Dr. Chris Muhlstein explains the challenge of studying materials that are too small to see with the naked eye. The technique some scientists use to observe individual atoms is similar to the technique of using touch to find out the size, shape, and location of objects in a dark room. By using a very small, sharp sensor, scientists can create an image of atoms.

Surface Tension: Making Paper Clips Float
In this video segment, the ZOOM cast relies on the surface tension of water to make paper clips float.

What is Matter?
This video/animation defines matter, mass, and volume using water as an example. The size, electrical charge and location of the subatomic particles of matter are described. Different types of atoms are called elements and organized in the periodic table. What happens to the properties of atoms when they exist alone or together?

Your Carbon Diet
Find out how much energy you use and some ways to conserve in this interactive activity from the NOVA/FRONTLINE Web site.