Guest Blog - written by Michele Perrin
Guest Blogger: Michele Perrin
As a high school teacher, I’ve used Vernier sensors for years to do science experiments. Now with the introduction of Mindstorms 2 and Vernier’s new NXT Sensor Adapter, I can use those same sensors in middle school science experiments. The adapter is about the size of LEGO’s sound sensor with a Vernier cable socket on one end and an NXT cable socket on the other. There are over 30 different sensors that are compatible with the NXT.
In the first graph, my students used a charge sensor to show how different objects can carry a positive or negative static charge on cold, dry days. The students vigorously rubbed a fleece blanket across a plastic book cover, then brought the plastic book cover near the charge sensor for the first five seconds and the fleece blanket near the sensor for the second five seconds. They used the Data Logger Section Analysis Tool to perform a linear fit on each side of the graph. This activity was even more exciting, because they wrote a small program with a sound block to play a tone that fluctuated depending on the strength of the charge (high charge, high pitch).
In the second graph, students used a hand dynamometer to measure the pinch strength of each finger. They used the Data Logger Text Annotation Tool to label each section. Since the hand dynamometer comes with a long cord, they used it to build a “robot walker.” The harder they squeezed the sensor, the faster the robot moved.
The third graph shows the readings taken from a pH sensor placed in a cup of detergent (an alkaline solution). About every 5 seconds, my students added one squirt of lemon juice (an acid) to the mixture. They built a motorized stirrer from NXT parts and they used the Data Logger Point Analysis Tool to label pH values at different points along the graph. This experiment was less messy than doing a color comparison on scraps of wet litmus paper.