Merry Christmas Eve

Pitsco has a guide on their website for building a spinning Christmas tree out of their Tetrix Prime Robotics Set. Their design uses elements from both the starter set (beams) and the expansion set (linkages). They even include a file for 3D printing 2 specialized parts for constructing the center support. But don't worry if you don't own a 3D printer or have time to run down to the local STEM center. There is also an option to build the center support out of wheels and axles (shown here). By adding a battery-operated set of LED lights, I've got a very festive (if somewhat nerdy) centerpiece for our Christmas table.

Science Journal App

I found out that Google's Science Journal app for Android phones can now be used with Vernier sensors and since I have a closet-full of Vernier sensors, I thought I'd try it out. Science Journal was originally created so that you could graph data from the sensors built into your Android phone (sound, light, motion, and barometer). The app is very easy to use, but limited in its analysis capabilities. What is nice, however, is that Google is encouraging 3rd-party vendors (like Vernier, Sparkfun, Jameco, and Pocketlabs) to develop compatible products and kits that capitalize on the features of Science Journal.

I tested Science Journal with Vernier's Go Wireless Temperature sensor. This waterproof Bluetooth device has a temperature range of -40 to 125°C (-40 to 257°F) with an accuracy of half a degree. The battery charge lasts about 2 hours, but you can easily recharge it with the same USB charger you use to charge your phone. You must have Vernier's Graphical Analysis app installed on your phone in order for their sensors to communicate with Science Journal, but once you do the initial setup, the Vernier sensor icon shows up right next to the Android sensor icons. Truthfully, having used both apps for data collection, there are times I would use Graphical Analysis over Science Journal, like when I need to do curve fitting or statistical analysis beyond the basic min/max/mean. But Science Journal is a simple way to couple my closet-full of Vernier sensors with the sensors in my phone.

Electrical STEAM

I recently stumbled on a few interesting products while volunteering at a STEAM workshop for Art Unleashed. Art Unleashed is a non-profit organization that has been incorporating science and engineering into some of their more traditional art classes for kids. Earlier this year, they offered a Saturday workshop on electricity. The kids made greeting cards accented with LEDs that lit up. They drew simple circuits onto card-stock using bare conductive paint from Sparkfun. This water-based paint conducts electricity eliminating the need for wires between the LEDs and coin-cell batteries. The paint comes in little squeeze tubes, so it is very easy to apply; but the paint has to be applied fairly thickly and it takes a long time to dry, especially in humid weather. This activity would work better spread over a couple days, so the paint can dry overnight.

Next we had the kids create light-up animals with Playdoh and modeling clay. The Playdoh is conductive, while the clay acts as an insulator. This is an excellent way to demonstrate the difference between a series circuit and an electrical short, because the LED won't light up if you just stick it and the battery into a single lump of Playdoh. Normally, you wouldn't connect an LED directly to a 9-volt battery or it would immediately burn out; but since the Playdoh has such high resistance, you can create circuits without the need for adding traditional resistors. Just be sure to have extra LEDs on hand for those kids who accidentally burn out their LEDs. I tried this activity with the off-brand Dough from Dollar Tree (4 different colors for only $1) and it worked beautifully.

For fast finishers, we set up stations with Snap Circuits. Snap Circuits are electronic elements mounted on big squares of clear acrylic - kind of like electronic jigsaw puzzle pieces. Kids snap the various elements together to create electrical circuits. We used the Snap Circuits Jr kits, which contain instructions for creating 100 different circuits from over 30 elements, like switches, sensors, lights, sounds, motors, etc. I'd heard about Snap Circuits at conferences, but never had a chance to try them out. I was so impressed, I bought my own set from Amazon (less than $20) and tried it out with my 4-year old niece. She loved it, especially the flying propeller.

Prime Expansion Set

I bought the new Tetrix Prime Expansion Set during the Cyber Monday sale at Pitsco. Unlike the Starter Set which primarily contains aluminum beams and plastic brackets, the Expansion Set includes a wide assortment of aluminum linkages, plates, and gussets. One major advantage is that you can use the linkages to make walking robots. 

The building instructions for the WalkerBot (shown above) are included in the user manual. I think it "loosely" looks like a reindeer - very apropos for this time of year. This model was significantly more difficult to build than the introductory models in the Starter Set. The premise of a linkage is to transfer the motor's rotational motion into linear motion, however if you don't get the linkages lined up perfectly, the whole model just locks up. It took a little finagling and re-positioning of joints to get the model to start walking. Once it did, its gait was rather clumsy and lumbering - kind of like a cockroach after a few cocktails. I haven't tested WalkerBot with kids yet, but I suspect the slowness of its awkward gait may not be as exciting as some of its wheel-based counterparts.