LecDem Blog

On the Physics of Work

Diagram of the concept of Work: a mass is moved over a distance S by a force F. Public domain image by artist すじにくシチュー

Happy Labor Day to all in the US!

(and belated greetings to readers elsewhere for whom Labor Day was in May.)

This holiday celebrates all kinds of work, but in physics Work is a more specific and mathematically defined quantity Today we’re taking a look at a couple of recent articles in The Physics Teacher that related to the concept of work in the classroom.

In physics, work is the energy transferred to or from a body via the application of force over a distance. Positive work is work done in the direction of motion, negative work is done in the opposing direction (or has components in those directions, in a 3-dimensional system). We sometimes, conversely, refer to energy as the ability to do work.

A recent paper in The Physics Teacher by G. Planinšič & E. Etkina, “Boiling water by doing work” (, shows some of this relationship between work and energy. As work is done on a system, moving a rope, some of the energy in the system is dispersed as heat. This heat is then seen to boil water. In their videos (linked in the article), you can see the relationship between work done on the system and temperature, and calculate for yourself the efficiency of energy conversion.

A paper in The Physics Teacher last year by P. Gash looks at potential energy and work in a more familiar mechanical system: a Slinky. In “A Slinky’s Elastic Potential Energy” (, we can see a detailed breakdown of the forces acting on the coils of a Slinky. You can check out the experimental data for yourself and calculate the work done by gravity on the spring. It’s a handy reminder that work in the physics sense doesn’t always mean human labor!

We have many demonstrations in our collection relating to physical work. Section C8 of our demonstration index is all about the mechanics of energy, power, and work; all are useful in the classroom, and many can be tried at home as well with materials you have on hand! There are many other demonstrations that explore energy and work as well, from thermodynamics experiments like the one in the paper above, to the newly repaired J4-31: Energy Stored in a Capacitor, which shows a capacitor that holds enough energy to let a motor do the work of lifting the capacitor itself against gravity. Now that’s a nice bit of work!

 J4-31: Capacitors and devices their energy can drive





More Articles ...

  1. Demonstration Highlight: Buoyancy
  2. STEM News Tip: Hurricane Ida
  3. Welcome to Fall 2021!
  4. Demonstration Highlight: Rotating Chair and Weights
  5. Demonstration Highlight: Electric Fields
  6. STEM News Tip: Donna Hammer wins Board of Regents Award
  7. Demonstration Highlight: Pendula of Different Masses
  8. STEM News Tip: Keep An Eye Out For Meteors This Month!
  9. Demonstration Highlight: Galileo's Pendulum
  10. STEM News Tip: UMD Tech Spin-Offs Highlighted
  11. STEM News Tip: APS Public Engagement Webinars This Week
  12. Demonstration Highlight: Chaotic Pendula
  13. STEM News Tip: AIP Reports on National Survey of High School Physics
  14. Demonstration Highlight: Charged Balloon
  15. STEM News Tip: AIP Celebrates 90th Anniversary This Month
  16. STEM News Tip: Prof. Alicia Kollár Receives NSF Award
  17. Happy 145th birthday to Harriet Brooks
  18. Demonstration Highlight: Hookes Law and SHM
  19. STEM News Tip: NASA STEM Stars Program
  20. STEM News Tip: Scientific American on the Future of Particle Physics
  21. Demonstration Highlight: Astro Blaster
  22. STEM News Tip: AIP TEAM-UP Webinar With Dr. Jami V Miller & Prof Kelly Nash
  23. Demonstrations Highlight: Lenz's Law
  24. STEM News Tip: NASA EPDC Outreach Programs
  25. STEM News Tip: Earth Observation Hackathon
  26. Profiles in Physics @ UMD: Prof. Manuel Franco Sevilla
  27. Demonstration Highlight: Inertia of a Lead Brick
  28. STEM News Tip: #BlackInAstro Week 2021
  29. STEM News Tip: New Research on the Physics of Viruses
  30. Demonstration Highlight: Laser Waterfall
  31. Celebrating the birthday of Chien-Shiung Wu
  32. Demonstration Highlight: Cosmic Ray Detector
  33. STEM News Tip: Eclipse Season
  34. STEM News Tip: Non-Newtonian Fluids for Cookout Season
  35. Happy Graduation!
  36. Demonstration Highlight: Coănda Effect
  37. STEM News Tip: Raman Spectroscopy for COVID-19 Testing
  38. STEM News Tip: NMAAHC on Experiences of African Americans in STEM
  39. STEM News Tip: Physics Today features classic article on computers in physics education
  40. Demonstration Highlight: Diffusion Distribution Models
  41. STEM News Tip: APS Begins Public Engagement Webinar Series
  42. STEM News Tip: KiNET-X Experiment Launches from Wallops Tonight
  43. Demonstration Highlight: Projectile Motion - Pellet and Falling Target
  44. UMD Physics Summer Programs 2021
  45. STEM News Tip: Prof. Buonanno elected to NAS
  46. Demonstration Highlight: Hill Track
  47. STEM News Tip: Physics Today interviews Shirley Ann Jackson
  48. Demonstration Highlight: Rotating Rings
  49. STEM News Tip: Earth Day 2021
  50. Demonstration Highlight: Tyndall's Experiment
  51. STEM News Tip: Atom interferometry in free fall
  52. Demonstration Highlight: Smoke Vortex
  53. Demonstration Highlight: Eddy Current Pendulum
  54. STEM News Tip: Measuring the gravitational force of tiny masses
  55. Demonstration Highlight: Plane Mirror
  56. STEM News Tip: The Physics of Music Recital Rooms
  57. Demonstration Highlight: Diameter and Circumference
  58. Demonstration Highlight: The Theremin
  59. STEM News Tip: Physics Today on Physicists & Mental Health in the Pandemic
  60. Demonstration Highlight: Centers of Mass
  61. STEM News Tip: Follow Along With Mars In March!
  62. Demonstration Highlight: Visible and Invisible Spectra
  63. Demonstration Highlight: Brass Barbell
  64. STEM News Tip: NASA's Mars 2020 Has Landed!
  65. Profiles in Physics @ UMD: Dr. Kate O'Neill
  66. Demonstration Highlight: Discharging capacitor
  67. STEM News Tip: This Week on Mars
  68. Demonstration Highlight: Simple Harmonic Motion Video
  69. STEM News Tip: Science Policy 2021
  70. Demonstration Highlight: Flame Tube
  71. UMD Research Commons workshops return for 2021
  72. STEM News Tip: TRAPPIST-1 Planets
  73. Demo Highlight: Funnel Cart
  74. STEM News Tip: Space Launch News
  75. STEM News Tip: Comet C/2021 A1 (Leonard)
  76. Demo Highlight: Hydraulic Press
  77. STEM News Tip: NANOGrav and Low-Frequency Gravitational Waves
  78. Demo Highlight: Polarizers and Light Source
  79. STEM News Tip: AIP Oral History Interviews
  80. Demo Highlight: Newton's Cradle
  81. STEM News Tip: Phosphine and Venus Update: The Research Goes On
  82. A Festive Time: Happy Isaac Newton's Birthday
  83. STEM News Tip: Winter Solstice 2020
  84. Demo Highlight: Rolling vs. Sliding
  85. STEM News Tip: Space, Sun, Stones, and Streaming
  86. Demo Highlight: Suspended Slinky
  87. STEM News Tip: Geminids Meteors
  88. STEM News Tip: Physics Today Features Music & Acoustics for International Year of Sound
  89. STEM News Tip: National Math Festival Online
  90. Demo Highlight: Pendulum Length Ratio
  91. STEM News Tip: Arecibo Observatory to be Decomissioned
  92. Demonstration Highlight: Potential Well
  93. STEM News Tip: UMD Data Challenge 2021
  94. STEM News Tip: Space Launch System Tests Resume
  95. STEM News Tip: The Mathematics of a Pandemic
  96. STEM News Tip: Try NASA’s Eyes on for size!
  97. STEM News Tip: AIP Foundation & TEAM-UP Report
  98. Demo Highlight: Free Fall in Vacuum
  99. STEM News Tip: New Comet in the Neighborhood
  100. Demo Highlight: Van de Graaff and Pie Pans
  101. STEM News Tip: Upcoming Virtual Events with UMD Science
  102. Demo Highlight: The Shive Wave Machine with Prof. Peter Shawhan
  103. The Physics of Bats
  104. Demo Highlight: Electromagnet With Bang
  105. STEM News Tip: Webinar Series
  106. STEM News Tip: Sci-Fi Costumes at Air&Space Museum
  107. STEM News Tip: DOE on STEM Careers
  108. Demonstration Highlight: The Egg Crusher
  109. STEM News Tip: Upcoming SPS Virtual Colloquium with Dr. Nicole Gugliucci
  110. STEM News Tip: Physics Comedy at the Maryland STEM Festival
  111. STEM News Tip: Dean Steve Fetter wins APS Leo Szilard Lectureship Award
  112. Demonstration Highlight: Guitar & Oscilloscope
  113. STEM News Tip: 2020 Nobel Prize in Physics Announced
  114. Demo Highlight: Racing Balls 2
  115. STEM News Tip: Maryland STEM Festival 2020
  116. Demonstration Highlight: Fourier Analysis
  117. STEM News Tip: Learning Resources for Nuclear Power
  118. Today in Physics History: Neptune
  119. Highlight: Van de Graaff Generator Animation
  120. STEM News Tip: Exoplanet around a White Dwarf Star
  121. Animation Highlight: Pendulum Waves
  122. STEM News Tip: Quantum Fireside Chat with Nobel Laureate Bill Phillips
  123. Demo Highlight: Laser and Double Slit
  124. STEM News Tip: Phosphine on Venus
  125. STEM News Tip: COVID-19 and the Physics Job Market
  126. Highlight: Radio Waves and Faraday Cage
  127. Remote Teaching Resources
  128. STEM News Tip: New Gravitational Waves Discoveries!
  129. Atwood's Machine: Testing Newton’s Second Law
  130. STEM News Tip: Some new articles in science teaching & information, August 2020
  131. Demonstration Highlight: Masses Dropped and Shot
  132. STEM News Tip: Native American Physics & Astronomy
  133. STEM News Tip: Titan and its Atmosphere on APOD
  134. STEM News Tip: COVID-19 impact on research
  135. The Tablecloth, the Coin, and Other Adventures with Inertia
  136. Quantum Demonstration and Simulation: The Hydrogen Atom
  137. STEM News Tip: New Atmospheric Phenomena Spotted on Venus
  138. STEM News Tip: SPS Virtual Colloquium
  139. Demonstration Highlight: Simple Harmonic Motion & Uniform Circular Motion
  140. STEM News Tip: Meteor Showers and Rain Showers
  141. STEM News Tip: Sonic Tourism
  142. Demonstration Highlight: Electromagnet
  143. STEM News Tip: Mars 2020 launches this week!
  144. STEM News Tip: Nova Reticuli 2020
  145. How many demonstrations?
  146. STEM News Tip: Solar Observer webcast this week!
  147. STEM News Tip: Children Learning About Gears
  148. Space News: The Nancy Grace Roman Space Telescope
  149. Demo Highlight: Vector Addition
  150. Demonstration Highlight: The Pencil and Plywood Experiment
  151. Demo Highlight: The Ripple Tank and a Ripple Tank Simulator
  152. Demo Highlight: The Racing Balls in Slow Motion
  153. Happy birthday, Alexander Müller
  154. New Demonstration: The Paramagnetism of a Dysprosium Pendulum
  155. Welcome to Spring 2020
  156. Light Up the Night: Neon and "Neon" Lights
  157. A Heated Discussion In Class
  158. The Physics Soda Can Returns: Electrostatic Induction
  159. Physics Teatime 3: Do Not Try This At Home
  160. Introducing Our Newest Center of Mass Demonstration
  161. FLIGHT!
  162. Happy Birthday Carl Sagan
  163. Hot Air Balloon
  164. Upcoming Events at UMD Physics!
  165. Welcome to Fall 2019!
  166. Summer Hiatus
  167. Phun with Electrons: Particle or Wave?
  168. Physics Teatime 2: On The Making Of Tea
  169. On the Choosing of Demonstrations
  170. Teatime in Physics
  171. Happy Birthday to Émilie du Châtelet
  172. Seeing Sound: Vibrations on a Plate
  173. Women Nobel Laureates in Physics
  174. Coming Soon: Physics is Phun presents Induction and Deduction
  175. New Portable Ripple Tank
  176. Irene Joliot-Curie
  177. New Demos: Buoyancy and Electromagnetic Forces
  178. Falling into Free Fall
  179. Happy 100th Birthday Katherine Johnson!
  180. Demonstration Orders for the Fall Semester
  181. Welcome!