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PPPL Plasma Lobby Display Project. Fran Tursi and Melinda Flores July 13 th – July 24 th. Lobby Display. By: Dana Arose, high school student. Our contribution. First plasma made using lobby display…. Our Contribution. Mass-Flow Controller (MFC). MFC connection ↓. 0-5 VDC .
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PPPL Plasma Lobby Display Project Fran Tursi and Melinda Flores July 13th – July 24th
Lobby Display By: Dana Arose, high school student
Our contribution First plasma made using lobby display…
Our Contribution Mass-Flow Controller (MFC) MFC connection ↓ 0-5 VDC -15 VDC +15 VDC
Our Contribution Mechanical Control Valve
Results • Answers • 125 mTorr – 135 mTorr • Yes. Assuming pressure change is constant (2 mTorr /3 hours) Questions What pressure will produce pretty plasma? Will the mechanical control valve be able to maintain this pressure for 8 hours of operation?
“Unfinished Business” Safety valve MFC with better power source Touch screen/timer
Plasma Lab: The Glow Discharge Senior Physics St. Peter’s Prep Lesson Plan by: Melinda Flores and Fran Tursi floresm@spprep.org and tursif@spprep.org
Lesson Objective To learn what a plasma is To understand how to create a plasma To identify the conditions needed to create plasma efficiently
Anticipatory Set What are the states of matter? Classify the following states of matter.
Anticipatory Set What are the three states of matter? Classify the following states of matter.
Objective & Purpose Over 99% of the universe is in the plasma state of matter! By researching plasma we can achieve greater understanding of the universe and reap the benefits of its practical uses. We will study how plasma is created and how it can be produced efficiently. • Practical Uses include: • New manufacturing techniques • Consumer products • Prospect of abundant energy • More efficient lighting • Surface cleaning • Waste removal • Aerodynamic innovations
Instructional Input and Information Matter can move from one state to another by applying energy to it. When energy is applied the matter becomes more active and changes states. • In plasma you not only have neutral atoms, you have ions and electrons.
Instructional Input and Information • Different factors affect what state matter will be in (i.e. pressure and temperature) • Recall the following graph from your chemistry class:
Instructional Input and Information Paschen Curve • In studying plasma we will look at the following factors: • pressure • distance between parallel plates • breakdown voltage
Instructional Input and Information What makes plasma a state of matter? How do you know that plasma is created? Three specific events of interest. 1. Electrons are coming close to ions Neutral atoms (lowest energy) 2. Electrons collide with neutral atoms (high speed) ionized atom and electron (greatest energy) 3.Electrons collide with neutral atoms and excite them Light from neutral atom
Modeling You apply heat or energy You apply energy How do we go from solid to liquid? From liquid to gas? How do you think we will go from gas to plasma? We have a florescent bulb with mercury vapor. What do you think will happen when we apply electrical energy to the vapor? Plasma will be created !
Monitor and Adjust Popsicle stick questions: How many states of matter are there? Name them. Describe the characteristics of each state of matter. What is the most prevalent state of matter in the universe? How do we move from one state of matter to the next?
Guided Practice Activity: Glow Discharge Using a vacuum and electrical system students will create plasma (safety and procedure will be discussed first). Student will work with two variables, pressure and distance in order to determine their effect on voltage needed to create plasma (breakdown voltage). Students will label and draw the apparatus, record data at given distances, create a Paschen curve (pressure x distance vs. breakdown voltage), and determine the pressure-distance product needed to create plasma using the least amount of voltage.
Guided Practice Monitor Their Practice Observe students in groups and ask questions to ensure students: Have correct setup Vary distances between plates Vary pressure Record pressure, distance, total voltage, voltage of the resistor Calculate breakdown voltage Graph data (Paschen curve)
Closure Looking at your Paschen curve, what do you see that may be significant? If you were funding a plasma experiment (you pay salaries, utilities, and for equipment) at what pressure-distance product would you want to produce plasma? Why?
Independent Practice Look at the following video: http://www.youtube.com/watch?v=os2xs6S4i-g Explain why this phenomena occurs and draw a representation of what is in the bulb before and after the bulb is illuminated. Label all parts in both of your drawings. In your journal, describe how plasma affects your life today and how you think plasma will affect your life in the future. Why do you think it is important to study efficiency in creating plasma?
Other considerations Materials Needed 2kV Power source Glass tube Parallel plates Wires 5000Ω Resistor Vacuum pump Digital multimeter tubing Time Needed: 2 hours • First day – Pre-lab • Second day - Gather data • Third day – Graph data and discuss results New Jersey State Standards • 5.7 (Physics) • A. 4, 5, 6 • B. 1, 2 Classroom Management • Safety - vacuum pump and power supply • Monitoring groups table to table
Other considerations Assessment • Lab practical – • Have each student adjust valve to specific pressure and measure plate distance to determine plasma breakdown voltage. Assessment • Exam Questions – • Paschen curve will be given for mercury: • Plasma was created at 100mTorr at 2.5cm. What was the breakdown voltage? • Paschen curve will be given for argon: • We are creating plasma at 300mTorr at 15cm. Is this the most efficient way to create plasma? Explain your reasoning.
Acknowledgements We would like to thank Jose Lopez (PARSE Institute), Jim Clayton (PARSE Institute), and Andrew Zwicker (PPPL), for their collaborative efforts in making this experience possible.
PRETTY PLASMA! Questions?