Scrub the Scum, Save the Shine: Engineering Motor-Driven Brushes
Student demonstrating an initial prototype with toothbrush, motor, and battery attachment.Copyright Ella Miesner & Melinda Wright
Students are challenged to design a motor-driven brushing tool that can successfully remove “scum” from a smooth surface while maintaining surface integrity (shine). Students are introduced to the concepts of surface tension, cohesion, adhesion, and friction as they investigate the effects of surface interactions. Students are introduced to the engineering concept of criteria and constraints and the challenge of balancing conflicting goals in a single product. Students work in teams to design, quantitatively test, and iteratively improve a device that maximizes scum removal while minimizing surface wear.
Engineers, scientists, and designers collaborate to create products that meet customer needs through a blend of creativity, scientific rigor, and practical engineering. Engineers apply their deep understanding of material properties and mechanics to design products with specific functions, such as cleaning surfaces without causing damage. Scientists develop experimental protocols to test whether these products meet the criteria and constraints defined by the designers. Engineers then use iterative testing and refinement, leveraging data-driven insights to improve the design and enhance functionality, ensuring the product meets both performance standards and customer expectations. This collaborative, engineering-focused process ensures the development of effective, user-centered products.
After this activity, students should be able to:
- Describe how the properties of different surfaces determine the frictional wear between the surfaces.
- Explain how surface tension is related to the cohesion and adhesion between liquid and solid surfaces.
- Evaluate engineering designs based on identified criteria and constraints to identify an optimal solution using the engineering design process.