The Balancing Act
Students visualize and interact with concepts already learned, specifically algebraic equations and solving for unknown variables. They construct a balancing seesaw system (LEGO® Balance Scale) made from LEGO MINDSTORMS® parts and digital components to mimic a balancing scale. They are given example algebraic equation problems to analyze, configure onto the balance scale, and evaluate by manipulating LEGO pieces and gram masses that represent terms of an equation such as unknown variables, coefficients and integers. Digital color sensors, built into the LEGO Balance Scale, detect any balance or imbalances displayed on the balancing scale. The LEGO Balance Scale interactively issues a digital indication of balance or imbalance within the system. If unbalanced, students continue using the LEGO Balance Scale until they are confident in their understanding of solving algebraic equations. The goal is for students to become confident in solving algebraic equations by fundamentally understanding the basics of algebra and real-world algebraic applications.
Balance scale LEGO model.Copyright 2013 Gisselle Cunningham, AMPS GK-12 Program, NYU-Poly
All engineers use equations to express different types of equilibriums that are seen throughout all types of systems used in our everyday lives. For instance, civil engineers must understand equilibrium forces in order to design bridges and buildings that do not collapse, where the supporting force is equivalent to the load force being applied. All engineers must understand equilibrium in order to keep balanced budgets of the funds available for projects that are equivalent to or greater than the funds being spent in order for the project to be successful. Electrical engineers must understand equilibrium in terms of the law of electricity, in which an electrical circuit is at equilibrium if the voltage produced in the circuit is equivalent to the total resistance times the current traveling through the circuit's electrical components. With electricity at equilibrium, engineers can build electrical circuits and devices such as computers, mobile phones and electric cars. Mechanical engineers must understand equilibrium for mechanical sustainability in order to place rovers on Mars or a person on a moon. All of these engineering equilibrium concepts require balanced equations; otherwise detrimental consequences can occur. For example, buildings and bridges would collapse, businesses and big projects would go bankrupt, electrical devices would be faulty or cause fires, and the $2.6 billion NASA rovers would crash land onto the surface of Mars. Thus, the concept of equilibrium and balancing equations is a vital and important skill across all engineering disciplines.
In addition, this activity maintains a technological connection to engineering through the use of color sensors. Designed and used by engineers, color sensors are one of the many digital components that modern robots use for sensory and autonomous navigation. Color sensors can detect the difference between light and dark contrast, which can be instrumental in visual sensory for navigation through a particular pathway, determining light vs. dark, for example night vs. day or shadow vs. no shadow, or perhaps picking up various objects of varying light and dark contrasts.
After this activity, students should be able to:
- Explain the principle idea of a "balanced" equation.
- Balance and solve one- or two-step algebraic equations.
- Describe the purpose and usage of a LEGO MINDSTORMS EV3 Intelligent Brick and sensors (especially a color sensor).