Summary
Students will be able to explain the fundamental concepts involved in electrostatics, such as charge, friction, conservation of charge, laws of attraction, and Coulomb’s Law.
Essential Question(s)
How is static charge generated and how do isolated charges separated by a distance relate to force?
Snapshot
Engage
Students watch a short video of a dog that has been charged and write a 20 word GIST statement to describe the physics of what they see in the video.
Explore
Students develop a method to levitate a ring made of grocery bag material using a balloon and paper towel. Students will write a 50-word GIST statement, explaining what happened using their academic vocabulary.
Explain
Students share GIST statements, and the teacher clarifies and formally defines terms and relationships involved in electrostatics including conservation of charge and Coulomb’s Law.
Extend
Students apply mathematical relationships to electrostatic problem solving and research additional applications of electrostatics.
Evaluate
Students will explain the process of lightning using academic vocabulary from the lesson.
Materials
Grocery bags
Balloons (large, round type works best)
Scissors
Paper towels
Picture of levitating bag and balloon (attached)
Practice Handout (attached)
Lesson Slides (attached)
Large, poster-sized paper
Markers, colored pencils, crayons, etc.
Engage
DAY 1 Show students the CuteWinFail: Static Dog video (it is recommended to turn off the annotations of this video—found under Settings designated by the gear symbol in the lower right-hand corner of the video box—before playing as they can obstruct the video itself). After the video, ask students to write a 20-word GIST or a Tweet Up summarizing the physics in the video. A GIST statement is a statement, typically 20-words, that sums up the student's understanding of the topic.
As students share their GIST or Tweet Up statements, write a list of the electrostatic terms on the board or on a large sheet of paper so they are visible to the class. Some terms to listen for are static, charge, friction, electrons, negative, positive, attract, repel, electric field, and force. They may only use two or three terms from this list. That is OK. The list will be expanded during the Explore section.
Explore
Show students the attached Picture of the levitating ring and balloon. Tell students they have 20 minutes to accomplish the same thing they are seeing in the picture, using a balloon to levitate a ring.
Each student or group will receive a grocery bag with scissors, a balloon, and paper towels in it. Tell the students they are allowed to use any and all of the materials for their experiment. Avoid the temptation to tell them how to accomplish the task.
Once all of the groups have accomplished the task, have a class discussion on how the activity was similar and how it was different from the charged video in the Engage portion. During the discussion, add to the list of terms from the Engage portion. Some additional terms from the discussion may include repel, charge(d), force, and gravity (weight).
Following the discussion, have students write a 50-word GIST statement incorporating all of the terms listed and explaining the relationships they observed in the activity.
Explain
Have students share their 20 word GIST or Tweet Up statements from the day before. At this time, begin to explain concepts as they relate to the students' ideas. Have students take notes or wait until after sharing the GIST or Tweet Up statements, then give students a more traditional opportunity to take notes using the attached Lesson Slides. It is most effective to do both, give notes as students share their ideas and afterward reinforce those main ideas by presenting the Lesson Slides. This way, there will be more opportunities to address misconceptions as students read their Tweets, students will feel as though they are contributing to classroom knowledge, and students will have two opportunities to get all the important information they need about this often confusing concept.
The laws of attraction state that objects with like charge will repel and charges with opposite charge will attract. Positive and negatives attract while positive-positive or negative-negative interactions will result in repulsion.
Coulomb’s Law states that a mutual force of attraction or repulsion exists between any two charges that is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. This is similar to Newton’s Universal Law of Gravitation.
Fe = (k q1q2)/d2 where k is a constant = 9 x 109 Nm2/C2
Extend
Students should begin this phase of the learning cycle by doing the attached problems in small groups. The answers to the problems are on the last page of the handout, but students should not be given the answers to the questions prior to attempting them. Even if the group isn't exactly sure how to solve all the problems, they should at least try. After all the groups have finished the questions, assign each group one question, or one part of a multi-step question, that they will answer for the class. Then, have a class discussion in which the groups share the solution to the problem they were given.
After all the questions are answered, show students the Electroscope Demo ScienceLibrary.info video. Pause it at 0:50. Explain that the device in the video is called an electroscope and it was invented hundreds of years ago to detect charge in objects. The stronger the charge, the greater the reaction of the leaves at the bottom of the device. Use an Exit Ticket with this prompt: "Based on what you've learned so far, explain what is happening and why it's happening." After prompting the students, show the video to the students again, stopping again at 0:50.
Collect the exit tickets.
Evaluate
Read a few responses to the Exit Ticket question. Then, show the entire Electroscope Demo ScienceLibrary.info video. The second half of the video has areas of charge labeled.
For the final part, students will be researching lightning and sharing their information with each other. Place students in groups of 2-3 and give them a poster-sized sheet of paper. An over-sized Post-it or a piece of bulletin board paper will work well. Explain to the students that they will be doing a Gallery Walk at the end of the next class period based on this prompt: What is lightning? Students need to research lightning and provide a thorough answer on their poster using drawings, diagrams, labels, and text. They should include all the terminology from this lesson on their poster. The rest of the hour should be used for researching lightning online or in books. Students should use the next class period to finish their research, finish their posters, and do the gallery walk.
Resources
Bone, A. (10 Feb. 2013). Electroscope Demo ScienceLibrary.info [Video]. YouTube. https://www.youtube.com/watch?v=Ngv2OlqFWXU
cutewinfail. (2 Aug. 2011). CuteWinFail: Static Dog [Video]. YouTube. https://www.youtube.com/watch?v=aO-phqmyqdY&list=PL817636B09D2C9B80&index=22
Dwyer, J. (30 Sept. 2005). How Lightning Works. NOVA. https://www.pbs.org/wgbh/nova/article/how-lightning-works/
K20 Center. (n.d.). Bell Ringers and Exit Tickets. Strategies. https://learn.k20center.ou.edu/strategy/125
K20 Center. (n.d.). Gallery Walk/Carousel. Strategies. https://learn.k20center.ou.edu/strategy/118
K20 Center. (n.d.). Tweet Up. Strategies. https://learn.k20center.ou.edu/strategy/130
The Physics Classroom. (n.d.). Static Electricity - Lesson 3 - Electric Force. The Physics Classroom. https://www.physicsclassroom.com/class/estatics/Lesson-3/Coulomb-s-Law
