In this video segment adapted from Navajo Technical College, meet a dendroclimatologist who studies the relationship between precipitation and tree growth in the Navajo Nation.

Why do objects like wood float in water? Does it depend on size? Create a custom object to explore the effects of mass and volume on density. Can you discover the relationship? Use the scale to measure the mass of an object, then hold the object under water to measure its volume. Can you identify all the mystery objects?

Why do objects like wood float in water? Does it depend on size? Create a custom object to explore the effects of mass and volume on density. Can you discover the relationship? Use the scale to measure the mass of an object, then hold the object under water to measure its volume. Can you identify all the mystery objects?

In this first part of a two-part lab activity, students use triple balance beams and graduated cylinders to take measurements and calculate the densities of several common, irregularly shaped objects with the purpose to resolve confusion about mass and density. After this activity, conduct the associated Density Column Lab - Part 2 activity before presenting the associated Density & Miscibility lesson for discussion about concepts that explain what students have observed.

Concluding a two-part lab activity, students use triple balance beams and graduated cylinders to take measurements and calculate densities of several household liquids and compare them to the densities of irregularly shaped objects (as determined in Part 1). Then they create density columns with the three liquids and four solid items to test their calculations and predictions of the different densities. Once their density columns are complete, students determine the effect of adding detergent to the columns. After this activity, present the associated Density & Miscibility lesson for a discussion about why the column layers do not mix.

In this lab activity, students determine density differences of water samples with varying temperature and salinity levels. Students synthesize information to predict the effects of oil in given water samples.

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HideA critical component of this activity involves sharing team data with the entire class, done the old-fashioned way on the chalkboard. Details This activity begins with an exploration of a topographic map of the earth, ending with the question: Why is the distribution of topography on the earth bimodal? The students then collect two forms of data. They measure the density of the most common rocks that make up oceanic crust (basalt), continental crust (granite), and the mantle (peridotite). They also measure the density of several different kinds of wood, and how high each kind floats in a tub of water. In each case, they work in teams of two or three and then the entire class shares their data. Based on the data from the wood, they derive an equation that relates the density of the wood to the height at which the block floats in the water - the isostasy equation. They then substitute density values for real rocks into their equation to derive thicknesses for average continental and oceanic crust, and apply their knowledge in order to draw a cross-section of the crust across South America. This activity gives students a real, hands-on and mathematical understanding of the principle of isostasy.

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After students conduct the two associated activities, Density Column Lab - Parts 1 and 2, present this lesson to provide them with an understanding of why the density column's oil, water and syrup layers do not mix and how the concepts of density and miscibility relate to water chemistry and remediation. Topics covered include miscibility, immiscibility, hydrogen bonds, hydrophobic and hydrophilic. Through the density column lab activities, students see liquids and solids of different densities interact without an understanding of why the resulting layers do not mix. This lesson gives students insight on some of the most fundamental chemical properties of water and how it interacts with different molecules.

These two hands-on labs are about the role of temperature and salinity in governing the density of seawater, a major factor controlling the ocean's vertical movements and layered circulation. In the first activity students work in groups to determine the density of tap water and of tap water with salt, then compare the densities. The second activity investigates the role of temperature and salinity in determining seawater density. Students use a Temperature-Salinity (T-S) Diagram to examine the effect of mixing on density. A list of key concepts, essential questions, common preconceptions and more is included. These are part of the Aquarius Hands-on Laboratory Activities.

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

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

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.

Students prepare for this activity by working with a unidirectional flume with a sand bed. We adjust water depth, flow velocity, and channel slope to achieve a range of bed states, in an effort for them to understand the controls on bedforms. This portion of the activity could be done in lecture or via another exercise that makes use of digital video of actual experiments. The activity itself is a jigsaw: students form groups of three, each group responsible for plotting depth vs. velocity plots of bedform state for a single sand grain size range (0.10-0.14 mm, 0.5-0.64 mm, and 1.3-1.8 mm). These data are provided to them as Excel files and the data were directly 'stolen' from the original depth vs. velocity plots in Middleton and Southard (1984), Mechanics of Sediment Movement, SEPM Short Course Number 3. Datathief software (available free on the web) was used to steal the data. The data are arranged in columns: depth, velocity, and bedform type. Students must plot each of the different bedform types with a different symbol, then they have to define field boundaries. It is critical that they have never seen the original plots in their textbook. The goal is for them to derive them on their own, not to regurgitate what is in their textbook or elsewhere. After they complete their plots for each grain size range, the groups re-arrange themselves into groups of three with one representative from each of the grain size groups. They then must try to evaluate the effects of changing grain size on bedform state. Finally, after completing the exercise, the bedform analysis is linked to the cross stratification that is produced under conditions of high sediment fallout rates and the given bed state. The activity gives students practice working with realistic datasets, exposure to the role of physical modeling in sedimentary geology, and a chance to plot and interpret real data. Furthermore, it really solidifies the link between cross stratification and its dynamic interpretation from the rock record.

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This design challenge moves your students from passive to active learners through a cross-curricular, hands-on team challenge in direct correlation to real-world issues of water conservation. By creating prototype desalination plants and companies, students in grades 6-8 will understand how substances are separated, the need for freshwater conservation, and ultimately how a desalination plant works.

SYNOPSIS: In this lesson, students explore different methods of desalination.

SCIENTIST NOTES: This lesson teaches students about potable water scarcity and then explores desalination as a possible solution in water-stressed areas. Desalination technologies are introduced, and energy and environmental costs of desalination are discussed. A video resource explores a novel desalination technology, the Solar Dome, being built in Saudi Arabia. Students are tasked with designing and building their own solar still, and opportunity is given for design optimization. This lesson is recommended for teaching.

POSITIVES:
-This lesson can be multidisciplinary and can be completed in engineering, computer science, digital art, English or science classes.
-Students and teachers are given voice and multiple areas of choice in this lesson.
-Students become agents of change in their own communities, identifying problems and solutions.
-Students and teachers can make this conceptual, practical, or hands-on.
-This lesson can be spread out over several days and be considered a mini-unit.

ADDITIONAL PREREQUISITES:
-Students should be familiar with the basics of climate change.
-Students should be familiar with the basic scientific concepts of osmosis.
-Students should be familiar with basic engineering concepts like scaling and design.

DIFFERENTIATION:
-Students can work independently or in a group with adjusted requirements.
-Teachers can use subject and grade level vocabulary already being worked on or learned in class. Teachers can add vocabulary words in the glossary slide of the Teacher Slideshow.
-To further develop practical science or engineering skills, students can work together to create and implement a workable desalination solution at the school, home, or community level. Students can lead a workshop for family, an environmental club, or the community.
-Some students may wish to communicate their advocacy via social media. Make sure to follow all school rules and monitor students’ progress if you allow this in the classroom.

Water supply is a problem of worldwide concern: more than 1 billion people do not have reliable access to clean drinking water. Water is a particular problem for the developing world, but scarcity also impacts industrial societies. Water purification and desalination technology can be used to convert brackish ground water or seawater into drinking water. The challenge is to do so sustainably, with minimum cost and energy consumption, and with appropriately accessible technologies. This subject will survey the state-of-the-art in water purification by desalination and filtration. Fundamental thermodynamic and transport processes which govern the creation of fresh water from seawater and brackish ground water will be developed. The technologies of existing desalination systems will be discussed, and factors which limit the performance or the affordability of these systems will be highlighted. Energy efficiency will be a focus. Nanofiltration and emerging technologies for desalination will be considered. A student project in desalination will involve designing a well-water purification system for a village in Haiti.

Water supply is a problem of worldwide concern: more than 1 billion people do not have reliable access to clean drinking water. Water is a particular problem for the developing world, but scarcity also impacts industrial societies. Water purification and desalination technology can be used to convert brackish ground water or seawater into drinking water. The challenge is to do so sustainably, with minimum cost and energy consumption, and with appropriately accessible technologies.
This subject will survey the state-of-the-art in water purification by desalination and filtration. Fundamental thermodynamic and transport processes which govern the creation of fresh water from seawater and brackish ground water will be developed. The technologies of existing desalination systems will be discussed, and factors which limit the performance or the affordability of these systems will be highlighted. Energy efficiency will be a focus. Nanofiltration and emerging technologies for desalination will be considered. A student project in desalination will involve designing a well-water purification system for a village in Haiti.

Students design and build model landfills using materials similar to those used by engineers for full-scale landfills. Their completed small-size landfills are "rained" on and subjected to other erosion processes. The goal is to create landfills that hold the most garbage, minimize the cost to build and keep trash and contaminated water inside the landfill to prevent it from causing environmental damage. Teams create designs within given budgets, test the landfills' performance, and graph and compare designs for capacity, cost and performance.

The course considers the growing popularity of sustainability and its implications for the practice of engineering, particularly for the built environment. Two particular methodologies are featured: life cycle assessment (LCA) and Leadership in Energy and Environmental Design (LEED). The fundamentals of each approach will be presented. Specific topics covered include water and wastewater management, energy use, material selection, and construction.

Students learn the concept behind the engineering design of a polymer brush—a coating consisting of polymers that is “tethered” to a particular surface. Polymer brushes can be used on water filtration membranes as an antifouling coating. After designing a model that represents an antifouling polymer brush coating for a water filtration surface, students take on the challenge to engineer their brush design on the surface of a Styrofoam block (which serves as a model for a surface filter) using various materials.