Magic Sand, Milk Rainbows, and Engineers

Last month at ROCKit students got their hands dirty with hydrophobic sand, were visited by Dow STEM Ambassadors, and recognized National Engineers Week by becoming construction and electrical engineers.

Hydrophobic sand, or “magic sand”, is a fine sand treated with a water repellent fabric protector such as Scotchgard. The fabric protector causes the sand to repel water and remain dry even when submerged in water. Each student received their own sample of sand to explore in water to see how it reacts.

Dow STEM Ambassador volunteers visited each after-school location to teach students about surface tension using two different projects. In the first project, students were asked to form a hypothesis about how many drops of water, and soapy water, can fit on the surface of a penny. Each person then tested (and sometimes retested) their hypothesis. Lastly, students were given a bowl of milk and were asked to place several drops of food coloring in the milk. As soon as the kids touched a cue tip with soapy water to one of the drops of food coloring, a “milk rainbow” appeared. This effect is caused by (fat) oils in the milk and the soap interacting with each other.

To recognize National Engineers Week, students were challenged to design a structure strong enough to hold several heavy books using rolled up newspaper and duct tape. Some students also created a very basic electrical circuit using insulated wires, AAA batteries, resistors, and LEDs.

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