Have you ever looked closely at water in a drinking glass? You might notice the surface of the water is not completely flat, rather it forms a small lip, called a meniscus, that curls up around the edge of the glass. This occurs because of two forces: adhesion (the attraction between the water molecules and the glass) and cohesion (the attraction of water molecules with one another). Cohesion among water molecules gives rise to surface tension, or the way water’s surface acts like a stretchy “skin.” Surface tension helps prevent raindrops from breaking apart and allows insects such as water striders to walk on water without sinking. It also contributes to the water rising along the edge of the glass: As some water molecules are pulled up because of their attraction to the glass, they pull others on the surface along with them.
Each Tuesday is EducationTuesday here at Adafruit! Be sure to check out our posts about educators and all things STEM. Adafruit supports our educators and loves to spread the good word about educational STEM innovations!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.