TeachEngineering
Teach Engineering: Sudsy Cells
Students culture cells in order to find out which type of surfactant (in this case, soap) is best at removing bacteria. Groups culture cells from unwashed hands and add regular bar soap, regular liquid soap, anti-bacterial soap,...
TeachEngineering
Teach Engineering: Break the Tension
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...
TeachEngineering
Teach Engineering: Surface Tension Lab
Students extend their understanding of surface tension by exploring the real-world engineering problem of deciding what makes a "good" soap bubble. Student teams first measure this property, and then use this measurement to determine the...
TeachEngineering
Teach Engineering: Magic Magnetic Fluid
Students are introduced to a unique fluid--ferrofluids--the shape of which can be influenced by magnetic fields. This activity supplements traditional magnetism activities and offers comparisons between large-scale materials and...
TeachEngineering
Teach Engineering: Get Your Charge Away From Me!
This activity is an easy way to demonstrate the fundamental properties of polar and non-polar molecules (such as water and oil), how they interact, and the affect surfactants (such as soap) have on their interactions. Students see the...
TeachEngineering
Teach Engineering: Down With the Clip!
Students see how surface tension can enable light objects (paper clips, peppercorns) to float on an island of oil in water, and subsequently sink when the surface tension of the oil/water interface is reduced by the addition of a...
TeachEngineering
Teach Engineering: Let's Get Dirty
In a very hands-on activity, students observe and feel the differences between two cleaning methods, with and without hand soap, using coffee grounds to represent "dirt."Most of the dirt and bacteria on our hands is encased in a thin...
TeachEngineering
Teach Engineering: Surface Tension Basics
Students are presented with the question: "Why does a liquid jet break up into droplets?" and introduced to its importance in inkjet printers. A discussion of cohesive forces and surface tension is included, as well as surface acting...
TeachEngineering
Teach Engineering: Surfactants: Helping Molecules Get Along
Students learn about the basics of molecules and how they interact with each other. They learn about the idea of polar and non-polar molecules and how they act with other fluids and surfaces. Students acquire a conceptual understanding...