Students continue their exploration of the human senses and their engineering counterparts, focusing on the auditory sense. Working in small groups, students design, create and run programs to control the motion of LEGO® TaskBots. By doing this, they increase their understanding of the use and function of sound sensors, gain experience writing robot programs, and reinforce their understanding of the sensory process.

Students continue an examination of logarithms in the Research and Revise stage by studying two types of logarithms—common logarithms and natural logarithm. In this study, they take notes about the two special types of logarithms, why they are useful, and how to convert to these forms by using the change of base formula. Then students see how these types of logarithms can be applied to solve exponential equations. They compute a set of practice problems and apply the skills learned in class.

Students examine different types of fabric and their characteristics. Using magnifying glasses and sandpaper, they test and observe the weave and wear quality of fabric samples. By comparing the qualities of different fabrics they come to understand why so many different types of fabric exist and are able to recognize or suggest different uses for them.

In small groups, students experiment and observe the similarities and differences between human-made objects and objects from nature. They compare the function and structure of hollow bones with drinking straws, bird beaks, tool pliers, bat wings and airplane wings. Observations are recorded in a compare & contrast chart, and then shared in a classroom discussion, along with follow up assessment activities such as journal writing and Venn diagrams.

In the everyday electrical devices we use calculators, remote controls and cell phones a voltage source such as a battery is required to close the circuit and operate the device. In this hands-on activity, students use batteries, wires, small light bulbs and light bulb holders to learn the difference between an open circuit and a closed circuit, and understand that electric current only occurs in a closed circuit.

Students learn about complex networks and how to represent them using graphs. They also learn that graph theory is a useful mathematical tool for studying complex networks in diverse applications of science and engineering, such as neural networks in the brain, biochemical reaction networks in cells, communication networks, such as the internet, and social networks. Topics covered include set theory, defining a graph, as well as defining the degree of a node and the degree distribution of a graph.

In a multi-week experiment, students monitor the core temperatures of two compost piles, one control and one tended, to see how air and water affect microbial activity. They daily aerate and wet the "treated" pile and collect 4-6 weeks' worth of daily temperature readings. Once the experiment is concluded, students plot and analyze their data to compare the behavior of the two piles. They find that the treated pile becomes hotter, an indication that more microbes are active and releasing heat. Through this activity, students see that microbes play a role in composting and how composting can be used as a carbon management process.

Students explore the concept of biodegradability by building and observing model landfills to test the decomposition of samples of everyday garbage items. They collect and record experiment observations over five days, seeing for themselves what happens to trash when it is thrown "away" in a landfill environment. This shows them the difference between biodegradable and non-biodegradable and serves to introduce them to the idea of composting. Students also learn about the role of engineering in solid waste management.

Accuracy of measurement in navigation depends very much on the situation. If a sailor's target is an island 200 km wide, sailing off center by 10 or 20 km is not a major problem. But, if the island were only 1 km wide, it would be missed if off just the smallest bit. Many of the measurements made while navigating involve angles, and a small error in the angle can translate to a much larger error in position when traveling long distances.

The computer program's simulation of a Sonoran desert community should ultimately strengthen the student's comprehension of what is required for a natural ecosystem to sustain itself (remain in balance). This computer simulation program has great flexibility. It allows the student to manipulate the population numbers of five Sonoran Desert species. A species natural history attachment provides vital information for the students to familiarize themselves with each species' behaviors, its niche and food resource needs. The program includes two producers, the Saguaro cactus and the Ironwood Tree. It also includes 3 consumers, but their interactions both toward the producers and each other differ. The community's ability to remain in balance and sustain all five species so that none die out rests on the student's assessment skills enabling him to correctly identify these dependencies. The student learns by trial and error as he continues to fine tune the ecosystem that he maintains stewardship of.

Students investigate the property dependence between concentrations and boiling point. In section 1, students first investigate the boiling point of various liquid solutions. In section 2, they analyze data collected by the entire class to generate two boiling point curves, one for salt solutions and one for sugar solutions. Finally, in section 3, students use the data they have analyzed to determine how to create a solution that has a particular boiling point and is a cost-effective design.

Students learn how the total solar irradiance hitting a photovoltaic (PV) panel can be increased through the use of a concentrating device, such as a reflector or lens. This is the final lesson in the Photovoltaic Efficiency unit and is intended to accompany a fun design project (see the associated Concentrating on the Sun with PVs activity) to wrap up the unit. However, it can be completed independently of the other unit lessons and activities.

Students design, build and test reflectors to measure the effect of solar reflectance on the efficiency of solar PV panels. They use a small PV panel, a multimeter, cardboard and foil to build and test their reflectors in preparation for a class competition. Then they graph and discuss their results with the class. Complete this activity as part of the Photovoltaic Efficiency unit and in conjunction with the Concentrated Solar Power lesson.

With the help of simple, teacher-led demonstration activities, students learn the basic concepts of heat transfer by means of conduction, convection, and radiation. Students then apply these concepts as they work in teams to solve two problems. One problem requires that they maintain the warm temperature of one soda can filled with water at approximately body temperature, and the other problem is to cause an identical soda can of warm water to cool as much as possible during the same thirty-minute time interval. Students design their solutions using only common, everyday materials. They record the water temperatures in their two soda cans every five minutes, and prepare line graphs in order to visually compare their results to the temperature of an unaltered control can of water.

Students make a simple conductivity tester using a battery and light bulb. They learn the difference between conductors and insulators of electrical energy as they test a variety of materials for their ability to conduct electricity.

Students are introduced to the idea of improving efficiency by examining a setting that is familiar to many teenagers fast food restaurants. More specifically, they learn about the concepts of trade-offs, constraints, increasing efficiency and systems thinking. They consider how to improve efficiency in a struggling restaurant through delegating tasks, restructuring employee responsibilities and revising a floor plan, all while working within limitations and requirements. Finally, students summarize and defend their suggested changes in argumentative essays.

Students use simple household materials, such as PVC piping and compact mirrors, to construct models of laser-based security systems. The protected object (a "mummified troll" or another treasure of your choosing) is placed "on display" in the center of the modeled room and protected by a laser system that utilizes a laser beam reflected off mirrors to trigger a light trip sensor with alarm.

We design and create objects to make our lives easier and more comfortable. The houses in which we live are excellent examples of this. Depending on your local climate, the features of your house have been designed to satisfy your particular environmental needs: protection from hot, cold, windy and/or rainy weather. In this activity, students design and build model houses, then test them against various climate elements, and then re-design and improve them. Using books, websites and photos, students learn about the different types of roofs found on various houses in different environments throughout the world.

Is the food chain shown above accurate? Does the first link depict a producer, the second link a herbivore, and the third link an omnivore / carnivore? Students must correctly determine whether a species is a producer or consumer, and what type of consumer; herbivore, omnivore, or carnivore. Students are provided with a list of Sonoran Desert species and asked to construct, within their groups, several food chains. These food chains are then be used to construct a food web. In order to complete this activity, students must first research the individual species to understand their feeding habits.

Students work in pairs to create three simple types of model bridges (beam, arch, suspension). They observe quantitatively how the bridges work under load and why engineers use different types of bridges for different places. They also get an idea of the parts needed to build bridges, and their functions. The strength of model bridges is mainly a factor of the quality of materials used, and therefore they do not provide a clear visual representation of tension and compression forces involved. Yet, students are able to see these forces at work in three prototype designs and draw conclusions about their dependence on span, width and supporting structures of the bridge designs.