Water Sensor (Conductivity)
📌 The water sensor utilizes Play-Doh modeling clay because its salt content makes it ionically conductive.
⚡️ Connection involves a 9V battery, two Play-Doh "wires," and an LED; the LED lights up when water (which contains ions) bridges the gap between the two points where the water is added.
💧 Water increases conductivity because the salt ions from the clay dissolve, and the added water itself contains ions, completing the circuit.

Pressure Sensor
📦 This sensor is constructed using a shoebox, aluminum foil, and cardboard pieces to create two parallel conductive plates separated by a non-conductive gap.
⬇️ When pressure is applied to the top plate (e.g., by stepping on it), the two conductive surfaces move closer, closing the circuit and illuminating an LED light.
💡 This design can be used for security alerts (detecting presence) or novelty applications like signaling Santa's arrival under a Christmas tree.

Vibration Sensor
⚛️ The vibration sensor uses a cardboard base with two strips of aluminum foil separated by a small gap, reinforced by straw (popote) barriers acting as walls.
⚪️ Small Play-Doh balls are placed within the barriers; the sensor activates when vibrations cause these balls to move, align, and create a conductive bridge between the aluminum strips, turning on the LED.
🎉 This sensor is highly dynamic and interactive, requiring playful manipulation to align the balls and achieve conductivity.

Key Points & Insights
➡️ These experiments, part of an SMPCE initiative, serve as a basic introduction to sensors for children and adults.
➡️ The conductivity principle relies on ion movement, demonstrated by the salt in the Play-Doh and ions present in tap water.
➡️ Successful circuit closure in these DIY sensors is indicated by the illumination of an LED.

📸 Video summarized with SummaryTube.com on Nov 27, 2025, 23:59 UTC