This 18-minute video lesson looks at vapor pressure, volatility, and evaporation. [Chemistry playlist: Lesson 32 of 106].

DISAPPEARING WATER: THE ARAL SEA OVER TIME, FROM 1973 TO 2001 A time series is a powerful illustrative tool. Where in the case of Las Vegas we see the direct effects of people on the land, in the case of the Aral Sea, separating the countries of Kazakhstan and Uzbekistan, we see indirect, but no less dramatic effects on a different part of the world. The Aral Sea is actually not a sea at all. It is an immense lake, a body of fresh water, although that particular description of its contents might now be more a figure of speech than practical fact. In the last thirty years, more than sixty percent of the lake has disappeared. As you'll see in the visualization, the change over time is dramatic. In the 1970s, farmers and state offices opened significant diversions from the rivers supplying water to the lake, sending millions of gallons to irrigate cotton fields and rice paddies. So voluminous were these irrigation sluices that concentrations of salts and minerals began to rise in the shrinking body of water. That change in chemistry has led to staggering alterations in the lakes ecology, causing precipitous drops in the Arals fish population. A secondary effect of this reduction in the Aral Seas overall size is the rapid exposure of the lake bed. Powerful winds that blow across this part of Asia routinely pick up and deposit tens of thousands of tons of now exposed soil every year. This has not only contributed to significant reduction in breathable air quality for nearby residents, but also appreciably affected crop yields due to those heavily salt laden particles falling on arable land. In the following sequence of images, we see a series of Landsat scenes taken several years apart. As the years pass, we see the profound reduction in overall area covered by the Aral, and a commensurate increase in land area as the floor of the sea now lies exposed.

Students learn about energy and nutrient flow in various biosphere climates and environments. They learn about herbivores, carnivores, omnivores, food chains and food webs, seeing the interdependence between producers, consumers and decomposers. Students are introduced to the roles of the hydrologic (water), carbon, and nitrogen cycles in sustaining the worlds' ecosystems so living organisms survive. This lesson is part of a series of six lessons in which students use their growing understanding of various environments and the engineering design process, to design and create their own model biodome ecosystems.

Students explore heat transfer and energy efficiency using the context of energy efficient houses. They gain a solid understanding of the three types of heat transfer: radiation, convection and conduction, which are explained in detail and related to the real world. They learn about the many ways solar energy is used as a renewable energy source to reduce the emission of greenhouse gasses and operating costs. Students also explore ways in which a device can capitalize on the methods of heat transfer to produce a beneficial result. They are given the tools to calculate the heat transferred between a system and its surroundings.

Hands-on group activity in where children go outside to find clouds, document with pictures, and identify them.

Analysis, modeling, and design of heat and mass transfer processes with application to common technologies. Unsteady heat conduction in one or more dimensions, steady conduction in multidimensional configurations, numerical simulation; forced convection in laminar and turbulent flows; natural convection in internal and external configurations; phase change heat transfer; thermal radiation, black bodies, grey radiation networks, spectral and solar radiation; mass transfer at low rates, evaporation.

Students will investigate evaporation as a cooling process. They will witness that temperature is affected by moisture content and the process of evaporation. Next, they will explore websites related to the processes of evaporation and condensation. Students will apply gained knowledge to real-life situations, and will share their new knowledge with a person outside the classroom.

Sweep of Lake Chad, February 2001: Located on the edge of the Sahara and bordering four countries--Chad, Cameroon, Nigeria, and Niger--the immense area of this land locked lake has nearly disappeared in recent years. Persistent drought has caused the lake to drop from its former sixth place position in the list of worlds largest lakes; it is now one tenth its former size. The basin of the lake is not naturally deep, so the surface area of the lake tended to spread out, keeping the total depth to little more 23 feet (7 meters). In recent years, rainfall patterns have begun to change, and tributaries to Lake Chad have not been refilling the basin as rapidly as they used to. The lush, productive flora and fauna fed by the wetlands of the shallow lake have suffered as a result. This has led to significant changes for various communities of people that live in the vicinity of the lake. While for some the now exposed lake bed has enabled new land to be cultivated, much of the available fresh water that might have been used for irrigation is no longer dependable. As rainfall rates appear to be declining year after year, people living nearby develop even greater dependence on the lake, draining it even faster.

Lake Chad Disappearing between 1963 and 1997: Located on the edge of the Sahara and bordering four countries--Chad, Cameroon, Nigeria, and Niger--the immense area of this land locked lake has nearly disappeared in recent years. Persistent drought has caused the lake to drop from its former sixth place position in the list of worlds largest lakes; it is now one tenth its former size. The basin of the lake is not naturally deep, so the surface area of the lake tended to spread out, keeping the total depth to little more 23 feet (7 meters). In recent years, rainfall patterns have begun to change, and tributaries to Lake Chad have not been refilling the basin as rapidly as they used to. The lush, productive flora and fauna fed by the wetlands of the shallow lake have suffered as a result. This has led to significant changes for various communities of people that live in the vicinity of the Lake. While for some the now exposed lake bed has enabled new land to be cultivated, much of the available fresh water that might have been used for irrigation is no longer dependable. As rainfall rates appear to be declining year after year, people living nearby develop even greater dependence on the lake, draining it even faster.

Lake Chad Disappearing between 1963 and 1997: Located on the edge of the Sahara and bordering four countries--Chad, Cameroon, Nigeria, and Niger--the immense area of this land locked lake has nearly disappeared in recent years. Persistent drought has caused the lake to drop from its former sixth place position in the list of worlds largest lakes; it is now one tenth its former size. The basin of the lake is not naturally deep, so the surface area of the lake tended to spread out, keeping the total depth to little more 23 feet (7 meters). In recent years, rainfall patterns have begun to change, and tributaries to Lake Chad have not been refilling the basin as rapidly as they used to. The lush, productive flora and fauna fed by the wetlands of the shallow lake have suffered as a result. This has led to significant changes for various communities of people that live in the vicinity of the Lake. While for some the now exposed lake bed has enabled new land to be cultivated, much of the available fresh water that might have been used for irrigation is no longer dependable. As rainfall rates appear to be declining year after year, people living nearby develop even greater dependence on the lake, draining it even faster.

Introduces the theory and technology of integrated-circuit fabrication. Lectures and laboratory sessions on basic processing techniques such as diffusion, oxidation, epitaxy, photolithography, chemical vapor deposition, and plasma etching. Emphasis on the interrelationships between material properties, device structure, and the electrical behavior of devices. Provides background for thesis work in microelectronics or for 6.151.

Introduces the theory and technology of integrated-circuit fabrication. Lectures and laboratory sessions on basic processing techniques such as diffusion, oxidation, epitaxy, photolithography, chemical vapor deposition, and plasma etching. Emphasis on the interrelationships between material properties, device structure, and the electrical behavior of devices. Provides background for thesis work in microelectronics or for 6.151. This course introduces the theory and technology of micro/nano fabrication. Lectures and laboratory sessions focus on basic processing techniques such as diffusion, oxidation, photolithography, chemical vapor deposition, and more. Through team lab assignments, students are expected to gain an understanding of these processing techniques, and how they are applied in concert to device fabrication. Students enrolled in this course have a unique opportunity to fashion and test micro/nano-devices, using modern techniques and technology.

This lesson plan introduces the properties of mixtures and solutions. A class demonstration gives the students the opportunity to compare and contrast the physical characteristics of a few simple mixtures and solutions. Students discuss the separation of mixtures and solutions back into their original components as well as different engineering applications of mixtures and solutions.

In a class demonstration, students observe a simple water cycle model to better understand its role in pollutant transport. This activity shows one way in which pollution is affected by the water cycle; it simulates a point source of pollution in a lake and the resulting environmental consequences.

The lesson introduces students to the steps of the water cycle and rivers. They think about the effects of communities, sidewalks and roads on the natural flow of rainwater. Students also learn about the role of engineering in community planning and protecting our natural resources.

NBC's Lester Holt looks at the physically demanding pre-season ritual of NFL training camp. Douglas Casa, head of the Korey Stringer Institute at the University of Connecticut, and athletic trainers from the Pittsburgh Steelers explain what NFL players must do to stay hydrated and replenish the essential nutrients needed to maintain good health during rigorous practices. "Science of NFL Football" is a 10-part video series funded by the National Science Foundation and produced in partnership with the National Football League.

Using a household fan, cardboard box and paper towels, student teams design and build their own evaporative cooler prototype devices. They learn about the process that cools water during the evaporation of water. They make calculations to determine a room's cooling load, and thus determine the swamp cooler size. This activity adds to students' understanding of the behind-the-scenes mechanical devices that condition and move air within homes and buildings for human health and comfort.

Groundwater is one of the largest sources of drinking water, so environmental engineers need to understand groundwater flow in order to tap into this important resource. Environmental engineers also study groundwater to predict where pollution from the surface may end up. In this lesson, students will learn how water flows through the ground, what an aquifer is and what soil properties are used to predict groundwater flow.

Big cities influence the environment around them. For example, urban areas are typically warmer than their surroundings. Cities are strikingly visible in computer models that simulate the Earths land surface. This visualization shows evaporation rates predicted by the Land Information System (LIS) for a day in June 2001. Evaporation is lower in the cities because water tends to run off pavement and into drains, rather than being absorbed by soil and plants from which it later evaporates. Only part of the global computation is shown, focusing on the highly urbanized northeast corridor in the United States, including the cities of Boston, New York, Philadelphia, Baltimore, and Washington.