Living just north of Phoenix, we get the warm sunny 70° January weather, but we can drive 100 miles to the north to play in snow. Snow takes on a reverent beauty when you are just visiting it, playing in it, and having the air full of thick, downy flakes. When it makes unwanted intrusions, such as when I lived in New York, Ohio, and Iceland, it becomes more difficult to appreciate.

To the right you will see some snow fun pictures from our snow play in Flagstaff yesterday. It is interesting to see the evolution of “sledding”. Even in my childhood, toboggans were on their way out. Wooden sleds with two rails and a steering bar, like the Flexible Flyer, ruled the hills. I didn’t even see one of these on the hills.  The disc or flying saucer seems to be waning.  The flexible-foam, body length “sled” is the new king of the slopes. But what slides down the snow best?

The “coefficient of friction” (COF) is used to express the amount of friction between surfaces and this is proportional to the force pushing the surfaces together, or the weight of the rider and sled on the snow. The greater the COF the more friction there is. The COF for not-yet moving surfaces (static friction) is greater than sliding surfaces (kinetic friction). Engineers have measured different COFs (link). For instance, the kinetic COF for leather on oak is 0.52 and for those interested in glass-on-glass action, the kinetic COF is 0.4. Google has enlightened me. I had no idea there was so much research done on snow, and that there is a vibrant field called “snow engineering”, which might be called the ultimate snow job.  Without going too deep into it, the COF for a moving skier (ski on snow) was analyzed to be between 0.01 and 0.3. I’d have to think that metal on snow would be a lower COF than foam on snow. It is good to think about, and students could do some fun experiments to find out.

Virtual science experiences must engage students and must have rich interactions. If it is just a Flash animation, I am not ready to call it an “experience” when the term video is much more suitable. If a teacher is going to bring laptop carts into a room or sign up weeks ahead for the computer lab, they should have computer-learning experiences that feature an engagement, a significant interaction, a closure, and multiple means of assessment. 

“Sliding on Different Surfaces,” an Activity Object by Adaptive Curriculum, features these aforementioned characteristics. For an engagement, students play a game where they steer a sled down a hill while encountering different types of surfaces. If they steer over the surfaces with the least amount of friction, they will go faster. They receive a score based upon how well they did.

In the student interaction, students are in an office. They slide a pencil case across a desk and then mark the distance. Their mission is to find different things in the room such as a towel, newspaper, and sandpaper (obviously a rough office)  and see how the pencil case sliding distance varies.  (Elearning Physics Preview)

This elearning physics experience moves forward to an explanation of friction and factors that influence friction. There is an optional paper-and-pencil activity sheet that students can complete as they do the Activity Object, with two questions to be answered when they are finished.  The activity sheets promote writing and become a permanent record of their learning for their science notebooks. If a teacher has a projector or interactive whiteboard and is doing a whole class lesson, the activity sheet is even more essential.

After the closure, students move onto the multiple-choice assessment, where they answer five questions and receive instant feedback about their learning. Teachers can log in to access student scores for the assessment. They can also see how long students took doing the Activity Object. If students are up for a bit of gaming, with their new understanding of friction, they can go back to the game and improve their time.

I did the Activity Object and played the game, and I observed that compared to my 8 and 11 year old sons, my sled in Flagstaff went much farther than their sleds. I would like to think that this was because I selected the patches of snow with the least friction and thus I picked up more speed. But these foam “sleds” are not very steerable and so, unfortunately, I have to consider the competing hypothesis that since my mass is a wee bit more than my sons (well okay, actually my weight is about 50 pounds more than both of them together), this may have had an influence. Since momentum is equal to mass x velocity, my momentum should be much greater than my sons’, and thus it would take longer to bring me to a stop. An impulse (force x time) can change the momentum of an object. Since my momentum is much bigger, and assuming that friction is about the same, I coast longer and thus farther.

But I think I will choose the happier hypothesis – that my greater knowledge of friction, rather than greater weight, made me go farther. Which just goes to show the subjective side of science after a happy family day in the snow. 

When we add technology to our repertoire of science activities, the best uses are for areas that allow students to do things that they could not do before. A simulation that allows students to explore falling objects with different forces of gravity, like Adaptive Curriculum’s “Free Fall”, extends learning beyond the walls of a classroom.

In a similar way, the best probeware allows students to discover things beyond the ordinary science classroom. So, if a school only had a budget for one probe, I recommend that it not be a thermometer, pH, or voltage probe, but rather, PASCO’s Passport motion sensor. Combined with PASCO’s EZ-Screen, this product is so much fun that instead of selling soda to get supply money, a science teacher could charge students a quarter a try. It is more fun than the token games at our local movie theater.

Motion Sensor

The name “motion sensor” is confusing. One might think it could turn lights on and off when walking into or out of a room. But these don’t; they really should be called “distance detectors”. The detector emits sound pulses that travel outward, and if something is in the path, the sound hits it and bounces back to the detector.  It tells how far away a person or object is located, based upon how long it takes the wave to travel to and from the probe. Since it is measuring distance from a fixed point (the detector) in a specific direction, it can be used to track a person or object’s displacement versus time. When the person moves in or out, their displacement from the probe is indicated in the form of a line graph. Thus a student can make a real time displacement-time graph and instantly understand a topic that many students find confusing.

EZ-Screen

The group that designed EZ-Screen should get an award. It is bright, fun, and engaging, which is not easy to say about a lot of graphing software. I recommend starting with free explorations of what happens when students move in, move out, and rest. The graphs show immediately what happens.  Charging students twenty-five cents a try is recommended.

The most fun comes when students try to match a graph (see picture). They see a gray line graph on the screen and then try to walk in such a way that the graph is replicated. They see the graph that was created (scarlet) against the match graph (gray), and get a score (100 being the highest). Bringing in the element of competition amps up the engaging value.  (Like when I connected my son’s PS3 online and then played his NCAA 08 Football; competing against a real (even though unknown) person made it so much more interesting to play as the scarlet and gray team.) The match graph and the actual graph my 8 year-old son and his friend made is in the picture to the right. How could they have possibly known the sleep over would be this much fun?

Science Class

For science instruction, I break my class into small groups with each having a computer and a detector. They start with free exploration. Then they practice doing the first match graph. After a few trials, they have a competition to see who is the best for the second match graph. I tell them not to do the third and final match. Each group sends their top contender to the front probe, which is also connected to a projector. We then have the finals, to award the title of “Grand Displacement-Time Graph Champion”. This was great fun and learning for my middle school science children this semester, and for adult preservice teachers in previous semesters. If you set up a little bookie operation you can make some more money by taking bets on the finals. I recommend taking 10% of the action.

Of course, with this probe you can do other things as well with other PASCO software, like dropping a table tennis ball and seeing a free fall graph. And then you could go to Adaptive Curriculum to explore free fall with different gravitational forces.

Conclusion

While technology might be used because it makes some things easier, I think when we are on limited budgets, starting with things that we can’t easily do, or that are impossible to do with regular tools makes the most sense. So let your students explore other planets with Adaptive Curriculum, and let them see that some graphing is great fun with EZ-Screen and motion detectors. It’s just too bad that they don’t turn off the lights.

The question is… What will you buy with all the money you make?

Adaptive Curriculum's Free Fall

For the Record

I hope you know I was kidding about the quarters and 10% of the action on the betting. I prefer Twinkies and other lunch snacks instead of quarters and I limit myself to 8% of the gambling action. 

The references to Scarlet and Gray does suggest an affinity for Buckeyes. 

Some people use the term dataloggers instead of  probeware.  If you wear smell sensors connected to clothing armpits, these are called probewear, otherwise the term probeware is preferred.  

In my “Physics for Teachers” class, when student groups present hands-on lessons, they sometimes start with a YouTube video. They are usually well selected and they turn out to be interesting and short. These videos are easy to find and in a university setting easy to display. While some schools have blocked YouTube as a website because of some content, there are workarounds for downloading the videos as .flv files (such as TechCrunch) and playing or converting them with flv players (my favorite for the Macintosh is the free iSquint.

On August 12, 2008, Smartteaching.org posted their 100 top YouTube videos for teachers. Below, I present their science list.

Resources

Adaptive Curriculum’s “Making Sperm and Eggs: Meiosis” Uses Flash-based animations and interactions.