Each group needs:

• 1 toy LEGO^® racer car (or other pre-made toy car that rolls smoothly across a table and is less than 6 inches long)
• 1 disposable hand warmer (typically found at outdoor stores, pharmacies or online from large retailers)
• 6 inch x 6 inch pieces of the following materials (purchased at hobby and/or hardware stores):1/16-inch thick aluminum, ceramic tile, 1/8-inch acrylic/Plexiglas, 1/8-inch wood veneer

• 7 inch x 7 inch piece of fabric
• 6-inch embroidery hoop (for fabric frame)
• several lengths of masking tape
• 8-10 wooden craft (Popsicle) sticks or plastic straws
• Can You Trip It? Worksheet, one per person

Testing station(s) to share with the entire class:

• 2 inch x 2 inch plywood square one per testing station (use 1/2-inch plywood so it is sturdy)
• passive infrared sensor with a light bulb, preferably red (a PIR sensor is a motion sensor-controlled socket, see Figure 1; available in the lighting sections of home improvement stores)
• (optional) ultrasonic motion sensor (ultrasonic sensors are typically used in commercial buildings, see Figure 2; available online for $50-100; if possible, purchase a sensor that is designed to mount to a wall, not a ceiling)
• light socket with attached wiring and light bulb, preferably red (for use with the ultrasonic sensor)