Students conduct a simple experiment to model and explore the harmful effects of acid rain (vinegar) on living (green leaf and eggshell) and non-living (paper clip) objects.

Students are introduced to the differences between acids and bases and how to use indicators, such as pH paper and red cabbage juice, to distinguish between them.

Students are introduced to the classification of animals and animal interactions. Students also learn why engineers need to know about animals and how they use that knowledge to design technologies that help other animals and/or humans. 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 the biosphere's environments and ecosystems, learning along the way about the plants, animals, resources and natural cycles of our planet. Over the course of lessons 2-6, students use their growing understanding of various environments and the engineering design process to design and create their own model biodome ecosystems - exploring energy and nutrient flows, basic needs of plants and animals, and decomposers. Students learn about food chains and food webs. They are introduced to the roles of the water, carbon and nitrogen cycles. They test the effects of photosynthesis and transpiration. Students are introduced to animal classifications and interactions, including carnivore, herbivore, omnivore, predator and prey. They learn about biomimicry and how engineers often imitate nature in the design of new products. As everyday applications are interwoven into the lessons, students consider why a solid understanding of one's environment and the interdependence within ecosystems can inform the choices we make and the way we engineer our communities.

Students examine how different balls react when colliding with different surfaces, giving plenty of opportunity for them to see the difference between elastic and inelastic collisions, learn how to calculate momentum, and understand the principle of conservation of momentum.

Students learn about stress and strain by designing and building beams using polymer clay. They compete to find the best beam strength to beam weight ratio, and learn about the trade-offs engineers make when designing a structure.

In this math activity, students conduct a strength test using modeling clay, creating their own stress vs. strain graphs, which they compare to typical steel and concrete graphs. They learn the difference between brittle and ductile materials and how understanding the strength of materials, especially steel and concrete, is important for engineers who design bridges and structures.

Students learn about and experiment with the concept of surface tension. How can a paper clip "float" on top of water? How can a paper boat be powered by soap in water? How do water striders "walk" on top of water? Why do engineers care about surface tension? Students answer these questions as they investigate surface tension and surfactants.

Students create their own anemometers instruments for measuring wind speed. They see how an anemometer measures wind speed by taking measurements at various school locations. They also learn about different types of anemometers, real-world applications, and how wind speed information helps engineers decide where to place wind turbines.

We are surrounded everyday by circuits that utilize "in parallel" and "in series" circuitry. Complicated circuits designed by engineers are made of many simpler parallel and series circuits. In this hands-on activity, students build parallel circuits, exploring how they function and their unique features.

Everyday we are surrounded by circuits that use "in parallel" and "in series" circuitry. Complicated circuits designed by engineers are composed of many simpler parallel and series circuits. During this activity, students build a simple series circuit and discover the properties associated with series circuits.

Students observe the relationship between the angle of a catapult (a force measurement) and the flight of a cotton ball. They learn how Newton's second law of motion works by seeing directly that F = ma. When they pull the metal "arm" back further, thus applying a greater force to the cotton ball, it causes the cotton ball to travel faster and farther. Students also learn that objects of greater mass require more force to result in the same distance traveled by a lighter object.

Students use balloons to perform several simple experiments to explore static electricity and charge polarization.

Students observe and discuss a simple balloon model of an electrostatic precipitator to better understand how this pollutant recovery method functions in cleaning industrial air pollution.

Students learn about using renewable energy from the Sun for heating and cooking as they build and compare the performance of four solar cooker designs. They explore the concepts of insulation, reflection, absorption, conduction and convection.

Students learn about the many types of expenses associated with building a bridge. Working like engineers, they estimate the cost for materials for a bridge member of varying sizes. After making calculations, they graph their results to compare how costs change depending on the use of different materials (steel vs. concrete). They conclude by creating a proposal for a city bridge design based on their findings.

Student teams investigate the properties of electromagnets. They create their own small electromagnet and experiment with ways to change its strength to pick up more paper clips. Students learn about ways that engineers use electromagnets in everyday applications.

Students explore the many different ways that engineers provide natural lighting to interior spaces. They analyze various methods of daylighting by constructing model houses from foam core board and simulating the sun with a desk lamp. Teams design a daylighting system for their model houses based on their observations and calculations of the optimal use of available sunlight to their structure.

Engineering analysis distinguishes true engineering design from "tinkering." In this activity, students are guided through an example engineering analysis scenario for a scooter. Then they perform a similar analysis on the design solutions they brainstormed in the previous activity in this unit. At activity conclusion, students should be able to defend one most-promising possible solution to their design challenge. (Note: Conduct this activity in the context of a design project that students are working on; this activity is Step 4 in a series of six that guide students through the engineering design loop.)

As students learn more about the manufacturing process, they use the final prototypes created in the previous activity to evaluate, design and manufacture final products. Teams work with more advanced materials and tools, such as plywood, Plexiglas, metals, epoxies, welding materials and machining tools. (Note: Conduct this activity in the context of a design project that students are working on; this activity is Step 6 in a series of six that guide students through the engineering design loop.)