Jan 29, 2009

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.

6 comments:

Brian Davis said...

Very nice Michele! It looks like you and your students are taking advantage of the new 2.0 software, as well as your existing sensors. I had a couple of questions about your opinion of the Vernier sensors, and since you seem to have used them a lot, I thought I'd ask you :)

Which do you find using the most, in different ways?

Do you ever use multiple Vernier sensors at once? The cost of the NXT-to-Vernier link has stopped me so far, but I recently acquired a 2nd, so I was curious with your experience.

Do you miss the higher resolution that the Vernier sensors can provide to the Vernier hardware (the NXT doesn't give as fine a resolution as some of these sensors "native" abilities)? Would you pay for a higher resolution version, or is it just not needed?

Do you link the NXT to the PC via the USB cable, or have you found BT to be very helpful in this regard?

Personally, I'm starting to want an "input box" for such high-resolution sensor, to fully take advantage of them, but I'm not sure how much that's needed in education. As to the sensors, yes, they have a nice selection... I'm trying to use the gas pressure sensor currently to monitor the chamber pressure in a geyser model (yes, I'm building geysers in my kitchen... and instrumenting and logging them with LEGO. Is anyone surprised? sigh...)

--
Brian "watch out for the hot water" Davis

Anonymous said...

Michele,

Thanks for posting your students work! We've briefly played w/ NXT-G 2.0 using a sound sensor. I tried our legacy LEGO temp sensor but it doesn't work with NXT-G 2.0. It's good to know that the Vernier sensors will work with it.

LEGOmom

mperrin said...

I am lucky in having a variety of Vernier sensors that I use at least once a week in my classes. Most of our robots/experiments use just one sensor, but we used 2 for a plant waterer (soil moisture and gas pressure) and 3 for an aquarium monitor (pH, conductivity, and temperature). It’s hard to pick a favorite, but it’s always less stressful using the hand dynamometer with young kids, because it’s so rugged and doesn’t involve liquids. Our school computers don’t have Bluetooth, so we use a USB cable. The resolution seems fine for middle school students, but Mindstorms 2 doesn’t have nearly the data analysis features that Vernier’s LoggerPro software has.

David Levy said...

"Do you ever use multiple Vernier sensors at once"

My group of 5th and 6th graders had used two at once for the H.A.L.E Balloon Launch. The experiment actually made it on to page 3 of the Vernier Fall Newsletter.

The kids are all very excited about getting a hold of the NXT 2.0 software and its datalogging utilities. Although I have to admit that I thought it was a good learning experience for them to have to log the data out to a text file and import it into Excel.

Anonymous said...

David, I thought the exact same thing re: learning to log the data, write to a text and import into excel.... but the real-time logging is pretty fun.

LEGOmom

David Levy said...

I bet... and probably accessible to an even younger audience. Only a couple of my kids knew how to use Excel.

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