PRACTICAL PHYSICS APPARATUS FOR THE CLASSROOM Frank Sita Dept of Physics SUNY Buffalo State College 1300 Elmwood Ave Buffalo NY 14222 sitafrank aol com Dan MacIsaac Dept of Physics SUNY Buffalo State College 1300 Elmwood Ave SC222 Buffalo NY 14222 macisadl buffalostate edu Keywords apparent changes in weight gravity electroscopes static electricity force interactions make and take ABSTRACT This article addresses a very real problem in today s Physics classrooms textbooks and lab manuals require teachers to use equipment that is overly expensive As the size of our nation s schools and classes becomes increasingly larger the amount of money that will need to be spent to outfit a science department with the necessary materials to teach their students would simply become prohibitive I have proposed several demonstrations and modifications to experiments that can be conducted relatively inexpensively while continuing to maintain the integrity of the physics phenomenon Electricity and Apparent Changes in Weight are two standard topics included in the New York State Physics Core Curriculum I begin with a proposed make and take leaf electroscope and pith ball electroscope to help students understand static electricity For apparent changes in weight I provide a simple modification to the modified Atwood apparatus that requires teachers to purchase an inexpensive digital lab scale not from a science supply catalogue but from the Harbor Freight tool catalogue Overall I have tried to find ways to make Physics more financially accessible to both teachers and students Acknowledgements This manuscript addressed requirements for PHY690 Masters Project at SUNY Buffalo State College Both Electricity and Apparent Changes in Weight are two standard topics included in the New York State Physics Core Curriculum I begin with a proposed make and take leaf electroscope and pith ball electroscope to help students understand static electricity For apparent changes in weight I provide a simple modification to the modified Atwood apparatus that requires teachers to purchase an inexpensive digital lab scale not from a science supply catalogue but from the Harbor Freight tool catalogue Overall I have tried to find ways to make Physics more financially accessible to both teachers and students A primary topic that is addressed by the New York State Regents Exam in Physics Regents Exam is Electricity I usually begin teaching this unit with Static Electricity There are a plethora of labs that can be used to demonstrate the concepts related to this particular topic However one of the obstacles that I have faced in my attempt to demonstrate these concepts is the shear expense of some of the standard equipment that is required The Regents Exam consistently asks students to relate their knowledge of static electricity to the operation of a leaf electroscope When this topic is taught a teacher would like to have students use a leaf electroscope to discover the static electric phenomenon for themselves The typical square electroscope with glass windows that would be used for this laboratory exercise can cost upwards of forty five dollars each when purchased through the science supply companies Ideally a teacher might have students work in pairs therefore a class of twenty four students would require twelve electroscopes This would bring the total cost for this activity to five hundred and forty dollars If multiple teachers need this equipment simultaneously this can become extremely expensive A teacher could also follow a suggestion published in a 1968 article in The Physics Teacher Hilton 1968 The professor proposes using one electroscope purchased from a science supply company and placing it on an overhead projector to demonstrate the static electric phenomenon This way a science department might only need a few of these electroscopes but the phenomenon would only be modeled for the students Today we consider modeling as the first step in teaching It is always preferable to give students direct hands on experiences I have developed an inexpensive solution that the students seem to enjoy Rather than spending an inordinate amount of money to use the professional electroscopes the students in my classes create their own electroscopes which they can later bring home and use to demonstrate the concepts related to static electricity for their family members This is a big plus because as educators we all know that when someone is capable of explaining and demonstrating a phenomenon to others they have probably understood it themselves The assembly of this make and take electroscope requires simple materials that all teachers and or students have readily available You will need standard large paper clips solid not notched scotch tape heavy duty aluminum foil 5x8 index cards and a metric ruler The total out of pocket cost for a teacher would be about four dollars for three classes of 24 students each Once all of the materials are on hand students will need to follow the following steps for building the electroscope 1 Cut the index card in half lengthwise 2 Fold each of the two parts in half perpendicular to the lines on the card 3 Fold a one centimeter tab at one end of each of the two pieces 4 Attach the two pieces to each other by taping the tabbed end of one piece to the straight end of the other Repeat for the other side At this point you should have a square frame See Figure 1 5 Take a large paper clip and lay it down flat on the desk Fold the small loop away from the larger loop at the point at which the wire ends so that the loops are perpendicular to each other and both loops still exist See Figure 2 6 Using a pencil point or any thin sharp object poke a hole in the center of a side of the square frame this will be the top of the electroscope 7 Feed the large end of the paper clip through the hole until the short loop rests flat on the index card the student may need to unfold the paper clip to accomplish this Tape the short loop to the index card for stability 8 Using aluminum foil cut two strips approximately one centimeter by three and a half centimeters These will be the vanes of the electroscope See Figure 3 Once the aforementioned steps have been completed the students will each possess their very own leaf electroscope that is capable of detecting the static electric phenomenon However there is still one element missing that is necessary for this apparatus to be fully functional a charged object The standard
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