Graph theory is a visual way to represent relationships between objects. One of the simplest uses of graph theory is a family tree that shows how different people are related. Another application is social networks like Facebook, where a network of "friends" and their "friends" can be represented using graphs. Students learn and apply concepts and methods of graph theory to analyze data for different relationships such as friendships and physical proximity. They are asked about relationships between people and how those relationships can be illustrated. As part of the lesson, students are challenged to find the social graph of their friends. This prepares students for the associated activity during which they simulate and analyze the spread of disease using graph theory by assuming close proximity to an infected individual causes the disease to spread.

This lesson will discuss the details for a possible future manned mission to Mars. The human risks are discussed and evaluated to minimize danger to astronauts. A specialized launch schedule is provided and the different professions of the crew are discussed. Once on the surface, the crew's activities and living area will be covered, as well as how they will make enough fuel to make it off the Red Planet and return home.

Students learn about slope, determining slope, distance vs. time graphs through a motion-filled activity. Working in teams with calculators and CBL motion detectors, students attempt to match the provided graphs and equations with the output from the detector displayed on their calculators.

Students experience data collection, analysis and inquiry in this LEGO® MINDSTORMS® NXT -based activity. They measure the position of an oscillating platform using a ultrasonic sensor and perform statistical analysis to determine the mean, mode, median, percent difference and percent error for the collected data.

Students learn how volume, viscosity and slope are factors that affect the surface area that lava covers. Using clear transparency grids and liquid soap, students conduct experiments, make measurements and collect data. They also brainstorm possible solutions to lava flow problems as if they were geochemical engineers, and come to understand how the properties of lava are applicable to other liquids.

Students are introduced to the concept of light pollution by investigating the nature, sources and levels of light in their classroom environment. They learn about the adverse effects of artificial light and the resulting consequences on humans, animals and plants: sky glow, direct glare, light trespass, animal disorientation and energy waste. Student teams build light meters using light sensors mounted to LEGO® MINDSTORMS® NXT intelligent bricks and then record and graph the light intensity emitted in various classroom lighting situations. They are introduced to the engineering concepts of sensors, lux or light meter, and lumen and lux (lx) illuminance units. Through this activity, students also learn how to better use light and save energy as well as some of the technologies designed by engineers to reduce light pollution and energy waste.

Through investigating the nature, sources and level of noise produced in their environment, students are introduced to the concept of noise pollution. They learn about the undesirable and disturbing effects of noise and the resulting consequences on people's health, as well as on the health of the environment. They use a sound level meter that consists of a sound sensor attached to the LEGO® NXT Intelligent Brick to record the noise level emitted by various sources. They are introduced to engineering concepts such as sensors, decibel (dB) measurements, and sound pressure used to measure the noise level. Students are introduced to impairments resulting from noise exposure such as speech interference, hearing loss, sleep disruption and reduced productivity. They identify potential noise pollution sources, and based on recorded data, they classify these sources into levels of annoyance. Students also explore the technologies designed by engineers to protect against the harmful effects of noise pollution.

Students learn first-hand the relationship between force, area and pressure. They use a force sensor built from a LEGO® MINDSTORMS® NXT kit to measure the force required to break through a paper napkin. An interchangeable top at the end of the force sensor enables testing of different-sized areas upon which to apply pressure. Measuring the force, and knowing the area, students compute the pressure. This leads to a concluding discussion on how these concepts are found and used in engineering and nature.

Students calculate the viscosity of various household fluids by measuring the amount of time it takes marble or steel balls to fall given distances through the liquids. They experience what viscosity means, and also practice using algebra and unit conversions.

After conducting the associated activity, students are introduced to the material behavior of elastic solids. Engineering stress and strain are defined and their importance in designing devices and systems is explained. How engineers measure, calculate and interpret properties of elastic materials is addressed. Students calculate stress, strain and modulus of elasticity, and learn about the typical engineering stress-strain diagram (graph) of an elastic material.

Students obtain a basic understanding of microfluidic devices, how they are developed and their uses in the medical field. After conducting the associated activity, they watch a video clip and learn about flow rate and how this relates to the speed at which medicine takes effect in the body. What they learn contributes to their ongoing objective to answer the challenge question presented in lesson 1 of this unit. They conclude by solving flow rate problems provided on a worksheet.

Students learn about the form and function of the human heart through the dissection of sheep hearts. They learn about the different parts of the heart and are able to identify the anatomical structures and compare them to the all of the structural components of the human heart they learned about in the associated lesson, Heart to Heart.

Students learn about frequency and period, particularly natural frequency using springs. They learn that the natural frequency of a system depends on two things: the stiffness and mass of the system. Students see how the natural frequency of a structure plays a big role in the building surviving an earthquake or high winds.

In this lesson, students will learn that math is important in navigation and engineering. Ancient land and sea navigators started with the most basic of navigation equations (Speed x Time = Distance). Today, navigational satellites use equations that take into account the relative effects of space and time. However, even these high-tech wonders cannot be built without pure and simple math concepts basic geometry and trigonometry that have been used for thousands of years. In this lesson, these basic concepts are discussed and illustrated in the associated activities.

Students expand upon their understanding of simple machines with an introduction to compound machines. A compound machine a combination of two or more simple machines can affect work more than its individual components. Engineers who design compound machines aim to benefit society by lessening the amount of work that people exert for even common household tasks. This lesson encourages students to critically think about machine inventions and their role in our lives.

In this extension to the Ohm's Law I activity, students observe just how much time it takes to use up the "juice" in a battery, and if it is better to use batteries in series or parallel. This extension is suitable as a teacher demonstration and may be started before students begin work on the Ohm's Law I activity.

Students work to increase the intensity of a light bulb by testing batteries in series and parallel circuits. They learn about Ohm's law, power, parallel and series circuits, and ways to measure voltage and current.

The lesson begins by introducing Olympics as the unit theme. The purpose of this lesson is to introduce students to the techniques of engineering problem solving. Specific techniques covered in the lesson include brainstorming and the engineering design process. The importance of thinking out of the box is also stressed to show that while some tasks seem impossible, they can be done. This introduction includes a discussion of the engineering required to build grand, often complex, Olympic event centers.

Students act as civil engineers developing safe railways as a way to strengthen their understanding of parallel and intersecting lines. Using pieces of yarn to visually represent line segments, students lay down "train tracks" on a carpeted floor, and make guesses as to whether these segments are arranged in parallel or non-parallel fashion. Students then test their tracks by running two LEGO® MINDSTORMS® NXT robots to observe the consequences of their track designs, and make safety improvements. Robots on intersecting courses face imminent collision, while robots on parallel courses travel safely.

Students are presented with a short lesson on the Coulter principle—an electronic method to detect microscopic particles and determine their concentration in fluid. Depending on the focus of study, students can investigate the industrial and medical applications of particle detection, the physics of fluid flow and electric current through the apparatus, or the chemistry of the electrolytes used in the apparatus.