Archive for the “physics” Category

In a semi-darkened classroom at Coronado High School, the recessed computer projector shined down upon a slightly cushioned floor. David Birchfield, politely told me, “We only walk on that after we take our shoes off.” So I quickly jumped off. Ms. Mills and her physics class came in, and the students sat in chairs around the perimeter of the square mat, almost as though they were there for a martial arts exhibition.

Then the physics began. There was a handmade object that when you pushed a button it dropped its bottom. It had reflective tape so the mini-cameras around the room could pick up its motion and transmit it to a computer, which interpreted the data and then created dots on the mat to show the motion of the large object or the separated objects.

A student spun around in a circle and then pushed the button. The bottom sphere dropped and fell away from the object. From the dot pattern it was quite clear, and one student even said it spontaneously: “It moved away at the tangent.” No longer would these students have the misconception that a moving object would still hold the circular force because of its prior motion. Indeed, from Newton’s first law, it was apparent the straight-line motion of the object.

Students took turns trying it. Then to keep them engaged in their free exploration, there were a number of challenges issued, starting with “Let’s aim at Justin.” Then they aimed at a fixed target. Then at a target moving the same direction they were spinning, with a student walking and holding the target, and then at a target moving in the opposite direction.

After the class was over, I tried it as well, this time sans shoes. I have experienced the future, and it is on the floor. There is more power in an experience that is whole body, rather than just fingers on a keyboard or a mouse. Watching the physics class, there is also the learner interactions that make this a potentially powerful learning environment. To be sure, we will see applications like this in museums before it makes it into regular classrooms. Because it can be used with many content areas, some schools might have a SMALLab (Situated Multimedia Arts Learning Lab) for all their teachers to share. And no doubt the 3-D tracking system can be brought to use with interactive white boards, making their use more economical.

My thanks goes to Arizona State University’s David Birchfield, Kelly Phillips, Tatyana Koziupa, Mina Johnson, and Leanna Archambault for letting me experience the future. This will be a tool that will help students overcome misconceptions and experience science in a different way.

Comments No Comments »

When I was doing my sabbatical at the University of San Carlos (Cebu, Philippines), Ed Van den

fire-tornado

Berg (one of the really great guys in science education), would have the undergraduate secondary education science students put on physics and chemistry demonstrations for the local school children. It was a delightful way to give them experience teaching and expose children to the interesting world of science. In the picture, two of my students demonstrate their fire tornado. (See http://www.west.asu.edu/rillero/philippines.htm for more of my photographs from the Philippines.)

In this YouTube video below, a similar program is described called “The Little Shop of Physics.”


Comments No Comments »

The electronic Ohaus scales that I ordered a few years ago are slowly dying. Only half the digits are readable on the numeric displays or in some cases there are no readable numbers. At NSTA in Phoenix, I stopped by the Ohaus booth and the representative was not surprised when I told her this. Unfortunately, she informed me, the scales have only a one-year warranty. From the initial lot we bought, half are unusable.ohaus-scale

Using the scales in our science methods classes at Arizona State University, shouldn’t be taxing compared to ordinary high school, middle school, or elementary school use. So it surprised me that the LD50 (a biology term for half a population dying) was achieved so quickly. But maybe my expectations are out of line, our Honda Odyssey, my wife informed me today, has 170,000 miles on it. But a one-year warrant, really? That makes me wonder how confident the manufacturer is in their product.

I like how fast the electronic balances gave readings. No longer were drafts, fast walkers, or table shakers an issue in our classroom, as compared to the old reliable triple beam balance scales. I predicted the end to triple beam balances at the high school and an even quicker death to the elementary level pan balances. But, perhaps I was too hasty.

I am not sure if Ohaus scales are worse then others. The sales rep informed me that in the newer models, the problem has been addressed with the displays. That won’t benefit me; I will put my next order in with a different company. But she also told me of another issue that seems likely to affect most scales that are not top end. Adding too much weight can permanently damage the weighing device. Yikes! It seems like a common occurrence, especially when doing full inquiry experiences, that students would add too much weight. Indeed, it seems like there should be warning signs on the scales about maximum loads.And this brings up a final issue. Why is it that we can’t find good reviews of science apparatus? I have bought things that are great and things that are lousy; wouldn’t it be nice to have a place like CNET that helps us tell what is good and what is not. But if you have scale advice, please do leave a comment.

Comments 4 Comments »

We all want to avoid having children get hurt doing school science. We also don’t want teachers to avoid doing hands-on science because of fears related to safety issues in the science classroom. For the elementary school classroom there are a couple of valuable resources that can help teachers and administrators develop safer practices for science instruction.

These are:

Science and Safety: It’s Elementary (http://www.csss-science.org/downloads/scisaf_cal.pdf)

And

Safety in the Elementary (K-6) Science Classroom (http://membership.acs.org/c/ccs/pubs/K-6_art_2.pdf)

Many of these practices have been written with common sense in mind. And if you are safety minded, you are on the lookout for all the potential things that can go wrong and ways to prevent these accidents. Unfortunately, K-5 classrooms would not have some of this safety equipment, such as eyewash fountains, fume hoods, and safety showers, and probably most middle school science classrooms would come up short in these areas.

While going all virtual to avoid safety problems may be tempting, a more pragmatic solution is to avoid dangerous hands-on materials and be very careful to try science activities before hand, and monitor student behavior.

Technology For K-6 Science Safety

While technology is often thought of as electronic stuff, a better and wider view is that it is any human made products that make our lives better or safer. With this in mind, I present my top ten safety technologies.

1. Teacher Developed Safety Rules Contract: A teacher and students who are safety minded is probably the best defense against accidents. There should be no toleration of inappropriate behavior when doing hands-on science.

2. Goggles: Chemical splash safety goggles should be worn whenever what you are working with has the potential to hurt or damage eyes. Please don’t adopt the view, such as, “I use ammonia at home without goggles, so it is okay to use it in school without goggles.” An adult can decide not to use goggles at home and it is at their peril. If a teacher decides not to have students wear goggles with materials that could harm eyes, and eyes are damaged, the teacher will probably be held culpable, as will the administrators, the school, and the district.

3. Disposable Nitrile Gloves: From dissections to handling chemicals, these can prevent problems. And if a student is bleeding for any reason, an adult should put on gloves to help with the situation.

4. Locked Chemical Cabinet

5. Fire blanket and extinguisherFire Extinguisher

6. First aid kit

7. Proper waste containers

8. Rubber covered muslin aprons

9. Safety posters and signs

10. Non-mercury thermometers

Teachers should be urged to provide hands-on experiences for their students. But teachers are also responsible for the safety of their students.

Comments 4 Comments »

 

Video game flying the Wright brother's glider

Video game flying the Wright brother's glider

It is always exciting to experience the sites and sounds of an NSTA conference. From my first science teacher conference, it was an awakening for me to find out that there are others like me who share my passion for science and education but who did not have an abundance of money to buy materials and who feel time compressed—despite perceptions that teaches have a lot of free time.

 

picture-52I brought my family along for this trip because it corresponded with my sons’ spring break from school. Okay, I admit, I probably wouldn’t have taken them to New Orleans if not for these reasons. I do think, however, exposure to other cultures is a good thing, and New Orleans’ has more than its share of culture. We were even able to go to a locals only crawfish boil (see photo). That my sons might be too young to appreciate New Orleans culture could be suggested by both of them liking the cool stuff in the conference exhibitor’s hall better than any other part of their visit. They were particularly taken by the science curiosities of “Steve Splangler Science” store, where the energetic folks did some intriguing square bubble demonstrations for them and NSTA New Orleansthen they were able to activities including tossing bubbles with gloves and making gummy worms. They also liked Flinn Scientific where they watched an engaging rep make foam, just like the stuff I use to close holes in and around my house. Now, they are flying home Chemistry of Foamwith a bag full of free materials from Insect Lore including two butterfly larvae that should form a chrysalis in two weeks.

It seems that the giving of t-shirts has achieved greater popularity. I don’t recall, in my first ten years of conference going, ever getting a t-shirt. Then the tech folks started giving away t-shirts and now so are the science folks. My wife doesn’t understand my interest in getting t-shirts, and she has already placed two of them (from Learning.com) in the piles of stuff to give to our son’s teachers. But there is one shirt I intend to keep; it is by far the nicest t-shirt I received, and it was a gray-background and white lettering SPARK t-shirt. I received it from Pasco when I attended a presentation on their SPARK system. Pasco seems to have a great understanding of the needs of a science teacher! So often science technology companies seem like they are devoted to the AP physics or chemistry teacher, who doesn’t have a family, social life, and is not pursing coursework. These rare folks might be able to take the time to figure out how to use complicated tech stuff to do one lab, but most regular teachers find it daunting. SPARK appears to be a solution that is easy to implement, cost effective, and has lots of uses. It acts like a mini-computer with a monitor, and it has its primary function—using probeware. So the yearbook teacher won’t want to borrow your class set!

Comments No Comments »

I have the good fortune to be in beautiful Austin, Texas today for the Texas Computer Education Association’s (TCEA) annual convention. Austin is a delightful city, and this conference is huge. In a couple of hours I am going to be doing my presentation “Critical Thinking and TEKS Science Content Via Online Activities.”Critical Thinking, science content, On-line activities

I am placing the PowerPoint file here for participants and anyone else interested in this topic. Below are some titles and resources from the presentation. 

Click here to access the PowerPoint. tx-critical-thinking2

The text for the slides is presented below. 

What is Critical Thinking?

Some Elements of Critical Thinking

Design a Satellite

ž  describe types of equipment and transportation needed for space travel. (TEKS: 6.13)

ž  http://www.eduweb.com/portfolio/designsatellite/

The World of Goo

ž  demonstrate basic relationships between force and motion using simple machines including pulleys and levers (TEKS: 7.6)

ž  http://2dboy.com/games.php

Creature Creator

ž  prelude to Spore

ž  Free trial edition

ž  How can students making creatures

—  Develop science content?

—  Develop critical thinking?

—  Or both?

Adaptive Curriculum Activity Objects

ž Dancing with the Bees

—  TEKS 6.12: responses to external stimuli

ž Determining Planet Layers from Seismic Waves

—  TEKS 6.6 identify forces that shape features of the Earth; 7.2: organize, analyze, make inferences, and predict trends from direct and indirect evidence

ž Groundwater

—  TEKS 6.1: make wise choices in the use and conservation of resources;  6.14 groundwater

Comments No Comments »

Movie CameraMuch as we may try to deny it, we teachers have known this truth for years:  we’re boring.  Oh, we fight back gamely, but in a world of television and movies, music and video games, capturing students’ attention is a real challenge.  A decade or two ago, the problem was bad enough, but now!  Now there are iPods!  Now students have music, games, and videos on their cell phones!  What chance do we, poor teachers have?

Two years ago, I decided to try an experiment with my Physics class.  I decided to fight fire with fire.  If the kids want movies, let’s watch movies.  And I don’t mean those “educational videos”; I mean real, blockbuster Hollywood movies.  No one ever accused Vin Diesel of being boring.  No one ever accused Arnold Schwarzenegger of being an old stick in the mud.  No one ever accused Keanu Reeves of droning on and on in a monotone…um, yeah… 

Speaking of Keanu Reeves, the classic example of bad movie physics is the delightfully improbable Speed, with its climactic scene of a city bus jumping across a 50-foot section of missing freeway.  The kids know that such a thing could never happen, but when they work through the calculations to show that it couldn’t, they really gain a better understanding of why it doesn’t work.  For an extension activity, students can calculate how large a take-off angle the bus would need in order to make it across.  It’s not as large as one might think (or it wouldn’t be if one could ignore air resistance the way we so often do in introductory physics courses).

I recently completed Superhero Week, in which I had my class analyze scenes from Superman, Superman Returns, Batman, Batman Begins, and Spider-Man, looking for examples of directors playing fast and loose with the laws of physics.  Just to cite a few examples from the first of the Christopher Reeve Superman movies, Superman meets Lois on her rooftop and takes her out flying.  Why doesn’t she freeze?  How can she breathe at that altitude?  How come she can fly as long as she’s in contact with Superman, even when it’s just their fingertips touching?  When their hands come apart, why does she plummet straight down, rather than following the normal parabolic path of a projectile?  When Superman catches her, after many seconds of free-fall, how does she survive the impulse?  Shouldn’t she at least have a few broken ribs?  Bruises?

In the interests of honesty and full disclosure, I should admit that I did not arrive at the idea on my own.  A long-time fan of science fiction and fantasy novels, I first thought of using that avenue to generate interest, but as I searched for resources online (why reinvent the wheel, after all?) I stumbled across a fabulous website:  Intuitor’s Insultingly Stupid Movie Physics, now also available in book form.

Physics and CinemaAs I dug further, I turned up even more resources:  Bad Movie Physics: A Report Card, and 9 Laws of Physics That Don’t Apply in Hollywood. And then there’s my personal favorite (yes, I know; as good as Intuitor is, I think this one might be even better), a book called Don’t Try This at Home! The Physics of Hollywood Movies, by Adam Weiner.  My first year of doing this, I pretty much stuck with the suggestions from Intuitor and Adam Weiner.  Then, as I gained more confidence, I began searching out my own for movies to use.  Once you start looking, they aren’t hard to find.

Guest Posting by Jon Nauert 

LHS Physics and 9th Grade Science Teacher
LHS Tech. Rep./ Basmati Administrator
Lakewood School District Technology Trainer 

Comments 2 Comments »

The "World of Goo"Using gooey balls, in the “World of Goo,” to make towers and bridges is an engaging way to build conceptual ideas in physics, engineering, and chemistry. The game made by a team of two guys (Kyle Gabler and Ron Carmel) at “2D Boy” won the Innovation Award and Technical Excellence Award at the Independent Games Festival. Goo is available for PCs, Macs, and the Wii. IGN named Goo the best Wii game of the year.  In my house, the free trial download version of Goo won the “Win Over the Skeptical 11 Year-Old Award” for totally engaging my son—who proclaimed, “This is addicting!” My eight-year old son called it “very fun.”

That shows the power of Goo. A game that requires no instructions, but you proceed from level-to-level building things to transport the living goo balls. There is something satisfying about building the goo structures, and something powerful about completing the puzzle at each level. Okay, the goo ball creatures and game remind me a bit of the Zoombinis, and the puzzle contexts are not the greatest, but building the structures to solve the puzzle is intriguing and satisfying. And who wants to waste time learning elaborate storylines when there are goo structures to build?

In my trial of the free on-line sample, I built towers and then bridges. Then my 11-year old son took over, starting anew, and quickly blazed past me to get to build balloon structures to help fight gravity. Neither of us met the minimal goo ball rescue at the “Impale Sticky” level, but fortunately we were able to skip this level when we were left a few balls short.

Building a goo structure is difficult to describe but easy to do. You pull one of the goo balls and separate it from the structure. Two or three white “lines of force” (my term not theirs) appear and when you stop pulling it, the white lines become goo links joining the ball to the previous structure. Of course there is a lot of jiggling and the pull of gravity is evident. If you pull a ball too far away from the others, the lines of force disappear and you realize you need to put it closer.

Science Education and Goo

Linking goo balls forms triangular tresses, which are important units of engineering design. Through trial-and-error learning, we experience that triangle goo formations are easy to build and stable. It is a nice contrast, because it seems in the world of play (from Lincoln Logs™ to Legos™), rectangular formations dominate. The tresses are then used to build towers, bridges, and dangling structures. There is a nice science (and international touch) in the use of metric measurements such a “you have 4.4 meters to go.”

The physics of Goo feels pretty real, and this can be a bridge to many physics concepts. As you build structures, the notions of a good foundation and center of gravity come into play. Build it one way too far, and it falls down; keep the center of gravity above the base, and the tower rises. There is also a sense of harmonics/resonance/vibration in that if your structure starts to bend and bob, you have to be careful that your additions don’t cause more of this in an undesired direction.

At some higher levels of Goo, buoyancy comes into play, along with levers and moments, as balloons lift up lever arms. When this is applied to building a bridge, the balloon placement is critical because too much lift or too little gets the balloons popped. Placing the balloon closer or further from the pivot point can decrease or increase the lift.

For chemistry, the most obvious notion is the idea of adhesion and cohesion. Goo balls being attracted to other goo balls is cohesion. When they stick to something else, like the level where you have to climb up out of a canyon and make them stick to the walls, you have adhesion.

Goo problemsHow do you Goo?

If you are teaching an engineering class, I think you have good justification to buy a class set of the “World of Goo.” I also think this would make a great addition to the computers of an elementary school computer lab. I can imagine Mr. Cosgrove (my fifth grade teacher) saying: “After you finish your graphs, if you have time you can Goo.” But for stepping softly into the “World of Goo,” give your students an extra-credit assignment to download the free version (link) at home and complete a certain number of levels. They can use screenshots to prove (and display) their work.

Edu-Goo

Winning awards is great and selling lots of this game must be pretty exciting to the creators. But I think the next endeavor should be an Edu-Goo product line. The possibilities are endless so I will just name three: (a) Online competitions between classes, schools, or the world to see who can build the Goo bridge to support the most weight, (b) three-dimensional Goo structures so students can explore using triangular versus rectangular tresses, (c) DNA Goo, where students can construct DNA double helix molecules. Less exciting but useful are worksheets that can guide exploration and discovery. Edu-Goo could have a teacher contribution page so teachers can contribute ideas about educational uses of Goo. 

Comments 1 Comment »

picture-85Living 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.picture-84

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 fricsnowflakeanition, 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. 


Comments 1 Comment »

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’sFree 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

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.  

Comments 1 Comment »