The Relay

December 10, 2025  •  EPISODE 290

How does a simple relay help us understand electricity and circuits? In this episode of Science LIVE, Roger Billings breaks down the science behind the relay—the clever electromagnetic switch that makes it possible to control circuits with precision. Learn how relays work, why they’re essential in everyday electronics, and how this simple idea became a building block for modern technology. A clear, hands-on look at one of engineering’s most important tools.

About DrB

Dr. Roger Billings is a visionary innovator whose work has touched the lives of millions of students and transformed the landscape of education. Widely known as “DrB” to the countless kids who benefit from his groundbreaking Acellus learning system, Dr. Billings has dedicated his life to advancing education through technology. As part of DrB’s lifelong commitment to supporting education, Science LIVE was launched as a way to “give back” by mentoring students in conjunction with the Roger Billings Scholarship Program.


Read more about DrB » 
About the Roger Billings Scholarship Program »

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5,486 Comments

  1. Isophene

    I want to learn sign language!

    Reply
    • Karma

      I do too!!!!!! ☺️

      Reply
  2. Niyasia

    I love to watch Science Live

    Reply
  3. Tamari

    I love Acellus Science Live!!

    Reply
  4. David

    Everything is well explained and i never knew about WD40!

    Reply
  5. Nguyen

    I love Science live!

    Reply
  6. Pham

    Why do we use a relay in an electric circuit?

    Reply
  7. Harmony

    I never knew WD-40 means water displacement 40th formula. My family use WD-40 to make the doors stop squeaking in our house.

    Reply
  8. Karen

    Thank you for not only sharing but teaching such great knowledge.

    Reply
  9. William

    I didn’t really understand petabites till now

    Reply
  10. Chase

    I love learning about electricity!

    Reply
  11. Madison

    I love these and I think that it so cool that they do this for us❤️❤️❤️

    Reply
  12. Grace

    We really enjoyed watching this, thank you for all you do Dr. Billings! Never knew much about circuits.

    Reply
  13. Magnolia

    One of the best ones

    Reply
  14. Jack

    Great Episode about relays.

    Reply
  15. Ariadne

    I always thought WD40 was used for unsticking stuff!! I didn’t know there were OVER 2000+ certified uses!! Incredible! Also R-51 loves to claim everything for himself lol

    Reply
    • Kezra

      The ending. Of the lives are My favorit
      LOVE IT😍

      Reply
  16. Faryn

    I didn’t know that about WD40! LOVE SCIENCE LIVEEEE😁

    Reply
  17. Jeremiah

    I am amazed that I learned how WD40 was created. My mom used that stuff on our outdoor patio swing.

    Reply
  18. Levi

    Levi here, love these episodes. DrB is so meaningful behind each science based idea.

    Reply
  19. Savannah

    How many circuits can you put together

    Reply
  20. Jenica

    i really enjoy the live labs. I learn so much from these cool videos.

    Reply
  21. Mary

    I like watching the weekly science live. It is so cool to learn new things that I never knew.

    Reply
  22. Mary

    The story of how WD-40 was created is hilarious! It is very interesting to learn about the different inventions that were made and how they were made.

    Reply
  23. Laya

    I enjoyed learning about DNA and it’s ability to store information. Science is so amazing!

    Reply
  24. Malaysia

    Every Science live I watch teaches me something new.

    Reply
  25. G

    WD40 is so great that even NASA uses it of course.

    Reply
  26. Henry

    Space IS SO COOL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    Reply
  27. Axton

    My Dad knew the history of WD40 but my mom didn’t and now she said she is going to use it to clean stuff.

    Reply
  28. Malayna

    This was very well explained.

    Reply
  29. Brandon

    I actually did not know that about WD40, Thats crazy,

    Reply
  30. Faith

    Wow the in person Acellus stuff looks so fun. Whenever I graduate, I probably wouldn’t be able to come because Kansas city is very far away from here, but I wish I could 🙁

    Reply
  31. Jahan

    Very cool story about the WD 40. Also loved the explaination on how the relay works with electricity and circuits. Thank you for teaching us.

    Reply
  32. Amy

    I enjoyed this one. Learning about the foundational building blocks and mechanics of the electronics we use everyday is enlightening.

    Reply
  33. Julia

    I like the Science live videos!

    Reply
  34. Layan

    I LOVE SCIENCE LIVE

    Reply
  35. Violet

    Another fascinating video. and a lot of stuff I likely would have never learned otherwise. Thank you for putting this program up for everyone to watch!

    Reply
  36. Liliana

    I enjoyed this video a lot and very well explained.

    Reply
  37. Matteo

    I never knew that NASA used WD40!!

    Reply
  38. Zorion

    This makes me want to tinker with my own electronics at home!

    Reply
    • Kaiden

      Me and my dad love electronics we have all kinds of gadgets

      Reply
  39. Nadhia

    I really LOVE the science live.I hope you enjoy this too.

    Reply
  40. Nic

    I actually did know that about WD40, my grandpa is a mechanic and builder. He works with tools and has skills that he passes down to me when he can!

    Reply
  41. Eden

    Science Live is the best things I watch all week!!

    Reply
  42. Natalie

    Circuits are so interesting.

    Reply
  43. Grayson

    Thanks for the science live! love learning new things.

    Reply
  44. Kailey

    I never knew WD-40 means water displacement 40th formula. My family use WD-40 to make the doors stop squeaking in our house.

    Reply
  45. Karah

    That was so cool!!!!

    Reply
  46. Jesius

    DR. Billings you are amazing!

    Reply
  47. Khloe

    i love how much science lives have taught me

    Reply
  48. Harry

    The WD40 session was so interesting and shows you should never give up!

    Reply
  49. Makenzie

    Thank you for science live! I learn something new every time I watch.

    Reply
  50. Emma

    Will the graduation ceremonies be held in the conference center every year from now on?

    Reply
    • Ethan

      Hello my name is Ethan. go DrB go DrB!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

      Reply
  51. Sophia

    Super interesting! WD-40 was originally developed in 1958 to prevent rust and corrosion in aerospace application but you can use it on so many things. Never knew this is how it started.

    Reply
  52. Alex

    I like how Dr. Billings explains a simple relay because he breaks it down in a way that makes electricity and circuits easy to understand. He shows how a small current can control a larger one, which makes the whole concept click.

    Reply
  53. Jaden

    i didn’t know that about WD40

    Reply
  54. Henry

    R-51 Have an electro shot! 😂😂😂😂😂

    Reply
  55. Arabella

    I love this science live! This video is so educational and I love watching/listening to them. They are so educational!

    Reply
  56. Riley

    Wd40 works for so much stuff, my mom uses it to all the time.

    Reply
  57. Audrey

    I told my grandpa about wd40, and now he wants to give it to everyone as a gift.

    Reply
  58. Liam

    I just got a circuit set for Christmas. It’s really awesome.

    Reply
  59. Anthony

    i would love to learn about WD-40

    Reply
  60. Phoenix

    I am so grateful for the science lives!

    Reply
  61. Darby

    I love science live!

    Reply
  62. Vincent

    I love watching science live! It is the best thing to watch!

    Reply
  63. Ella

    Isn’t it risky not trademarking WD-40 with today’s technology? Couldn’t someone analyze it and figure out the formula?

    Reply
  64. Elisa

    What would happen to a circuit if there were no relays at all? Thanks

    Reply
  65. Antonio

    We love Dr. Billings

    Reply
  66. Dashiell

    WD40 is a wide-range utility that can be used in science for multiple purposes.

    Reply
  67. Aislynn

    No joke R51 drinking someone else’s drink. The exact same thing my 2 cats do.

    Reply
  68. Nathan

    The most surprising thing to me is that NASA uses WD40.

    Reply
  69. Sydney

    WD-40 is so versatile

    Reply
  70. Kerrington

    My Dad was just talking about a relay in his truck. Too funny!

    Reply
  71. Jaxon

    My dad always says you need 2 things in the house to help with repairs Duct tape and WD-40!

    Reply
  72. Caleb

    I’m learning but it’s fun. I love Acellus!

    Reply
  73. Amelia

    The relay is so important in electronics. I love STEM class.

    Reply
  74. Jovi

    I am enjoying learning new things from Science Live!

    Reply
  75. Caleb

    I’ve never heard about WD40 before so it was interesting to learn about. It’s also encouraging, it shows how you can try again even if you fail!

    Reply
  76. Jude

    Thank you Dr. Billings for Science Live.

    Reply
  77. Joshua

    Wd40 literally fixing everything

    Reply
  78. Rebecca

    I like WD-40 it’s works like a genius when it comes to oil stains like grease, tar, lipstick and crayon like my little sister draws on walls and floors.

    Reply
  79. Miyuki

    That’s so cool NASA uses WD40! I see my grandpa using this when the sliding door won’t close.

    Reply
  80. Dakota

    Science live episodes are so fun to watch and i love watching them

    Reply
  81. John

    We should always stay optimistic and keep going, even when it gets difficult. Even great inventors struggles and felt things were impossible at times

    Reply
  82. Victoria

    I guess WD40 is a very popular spray, didn’t know NASA uses it!

    Reply
  83. Emily

    I don’t think I ever would have thought to store data in DNA, wow!

    Reply
  84. Lillian

    This is one of my favorite science lives!

    Reply
  85. Laci

    I think it’s really cool that WD40 stands for Water Displacement 40th Formula because it took them 40 times to get it correct! Ha!

    Reply
  86. Faith

    WOW! Coherers are super cool! Thank you for teaching us Dr. Roger Billings!

    Reply
  87. Kalea

    R-51 is the best part!

    Reply
  88. Miyari

    I love every subject in acellus and there’s so much to learn and I’m excited to see whats next on acellus live!!

    Reply
  89. Opal

    Learning about the WD40 and all it’s different uses was cool! I want to be a scientist

    Reply
  90. Forest

    I would be very excited to meet my teachers in Kansas City at future events

    Reply
  91. Jadyn

    I am so grateful that I get to learn new things!

    Reply
  92. Ridley

    Is R-51 ok?

    Reply
  93. Maverick

    I am so thankful for electronics.

    Reply
  94. Mercedes

    I want to make a relay for a science project!

    Reply
  95. Jeremy

    Electricity has always facinated me.

    Reply
  96. Rylee

    How do you measure the speed in a relay experiment

    Reply
  97. Chloe

    My Dad uses WD40 too. I like watching these Science Live videos.

    Reply
  98. Jaxon

    i like how you turned on the light with the spoons. super cool!

    Reply
  99. Juliet

    I didn’t know all the things WD40 can be used for!

    Reply
  100. Aubrey

    I am so thankful for these science live episodes I learn so much every single week! Thank you!

    Reply
  101. Giovanni

    What is the difference between a relay and a transistor?

    Reply
  102. Abygail

    My dad used WD40 all the time

    Reply
  103. Juliet

    I love CIRCUITS SO MUCH!!! MORE VIDEOS ON IT PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    Reply
  104. Gip

    r – 51 you’re so silly and funny 🤣😂🤣😂🤣

    Reply
  105. Anthony

    Relays are so interesting. Thank you for explaining the process and the componets of the relay.

    Reply
  106. Will

    I never knew the company behind WD40’s name, just never really thought about the company name.

    Reply
  107. Tatum

    Dr Roger Billings makes it very easy to understand and walks us through it well every time, and i never knew there were that many uses for WD40.
    Thank you so much Dr Billings and science live team!

    Reply
  108. Tristen

    I’m always happy to learn more from Science Live!
    R-51 is so skilled he doesn’t even need coffee to focus even after a long day at Area-51.

    Reply
  109. Blake

    I cant believe how long WD40 has been around and i just found out how it was invented!

    Reply
  110. Connner

    Awesome video, thank you for teaching me new things

    Reply
  111. Hannah

    Hey from Oklahoma!

    Reply
  112. Travis

    I love r-51

    Reply
  113. Hana

    Can 4th Grade Students go to acellus world.

    Reply
  114. Mimi

    This was really cool to hear about. My dad is really into radios and I think he would love to hear about this!

    Reply
  115. Kimber

    Science live is so intriguing and fun!

    Reply
  116. Olivia

    im so grateful for this class!!

    Reply
  117. Nathaniel

    When I was younger, my mom got my sister and me a circuit set and figuring out switches and relays hands on was one our coolest toys. Learning how to control circuits for sound or lights or movement made sense when we could manipulate the pieces to learn what worked. This Science Live was next level! Thanks for taking the time to share scince with us.

    Reply
  118. Huet

    Such a great episode! One of my favorites! I loved learning about DNA and cell storage and WD-40!!!

    Reply
  119. Cayley

    I never knew about WD40, that was so interesting!

    Reply
  120. Salem

    Dr.Billings is so smart!

    Reply
  121. Hudson

    I love acellus!

    Reply
  122. Mackenzie

    The new acellus convention center looks very cool

    Reply
  123. Magdalena

    Watching from Georgia!

    Reply
  124. Layla

    To be honest only taking 40 tries to make WD40 is pretty impressive. You’d think it would take alot more trial and error.

    Reply
  125. Lillian

    The story behind how WD 40 was made is crazy.

    Reply
  126. Justin

    I liked learning about the relay

    Reply
  127. Genesis

    I am so sorry I forgot to comment and just remembered!! I was gonna say I love science live so much! It’s taught me so much about science and I think I wanna pursue an education in it now!

    Reply
  128. Braelyn

    I love watching science live! It is the best thing to watch!

    Reply
  129. Sergio

    I love all the ways there are to use WD40.

    Reply
  130. Autumn

    So grateful to be learning new things!

    Reply
    • Aubrey

      Loved this episode!

      Reply
  131. Lucas

    I love watching science live! It is the best thing to watch!

    Reply
  132. Joshua

    That’s funny that’s NASA uses WD40.

    Reply
    • Kaedynce

      I love watching these! I learned a lot about NASA that i didn’t know before!

      Reply
  133. Mason

    I actually did know that about WD40, my grandpa is a mechanic and builder. He works with tools and has skills that he passes down to me when he can!

    Reply
    • Thoie

      Happy new years!! From lousisana, love this weeks science live

      Reply
  134. Lydia

    Thank you Dr. Billings!

    Reply
  135. Finn

    R51 used organic grounding😂

    Reply
  136. Ruby

    I actually did know that about WD40, my grandpa is a mechanic and builder. He works with tools and has skills that he passes down to me when he can!

    Reply
  137. Kaydence

    it’s so crazy that nasa uses wd 40

    Reply
  138. Arya

    How old do you have to be to graduate from Acellus?

    Reply
    • Arabella

      You have to be 16 years old.

      Reply
  139. Aniya

    I enjoyed everything about this video and how each subject was explained.

    Reply
  140. Aiden

    To be honest only taking 40 tries to make WD40 is pretty impressive. You’d think it would take alot more trial and error.

    Reply
  141. Bradley

    This is amazing!

    Reply
  142. Jedidiah

    WD40 can be used for so many things

    Reply
  143. Evaleeya

    I liked seeing Acellus World and would love to go there someday! Also, I liked hearing about DNA being used for storage.

    Reply
  144. Lerah

    WD-40 has so many ways to use it. Im going to tell my mom all these ways

    Reply
  145. Arya

    R 51 is hilarious😂😂😂

    Reply
  146. Waylon

    Ive been really liking the episodes on radio waves. This lesson on relays was really good. I cant wait for the next science live.

    Reply
  147. Kameron

    So much fun learning about DNA thank you!

    Reply
  148. Irelynd

    I never knew it to 40 try’s to make WD40!! I liked learning about the DNA facts as well. Dr. Billings is so smart. 😀

    Reply
  149. Mattox

    That’s so cool to learn about WD40!

    Reply
  150. Kalliope

    I liked hearing about how WD-40 was invented and proving to never give up!

    Reply
  151. Genevieve

    This episode is great. Thanks, Acellus!

    Reply
  152. Layne

    Science live episodes are so interesting!

    Reply
  153. Luci

    whoa! I didn’t know that we found a way to store data in dna.

    Reply
  154. Bailey

    WD-40 is actually something that cool to use!!!

    Reply
  155. Aidan

    I will be trying wd 40 on lego!

    Reply
  156. Maya

    I really liked to learn about WD40!

    Reply
  157. Maya

    I love science live!!!

    Reply
  158. Alexis

    I told my dad I was learning about WD-40. He thought that was pretty cool.

    Reply
  159. Oliver

    Thank you very much for making these videos. I love Science Live!

    Reply
  160. Reagan

    This was great I did not know that it took 40 try’s to make WD40!

    Reply
  161. Emma

    Thank you Dr Billings! I loved learning about the DNA and WD40!! 🙂

    Reply
  162. Hunter

    Are radio waves the same thing as WiFi?

    Reply
  163. Hannah

    The story about coating the NASA rockets was interesting.

    Reply
  164. Karly

    It’s neat how those little balls make electricity.

    Reply
  165. Cory

    watching from Ohio! theres so many things you can do with WD40!

    Reply
  166. Victoria

    its crazy how they came up with WD40!

    Reply
  167. Brody

    Thank you for another week of education

    Reply
  168. Emma

    Thank you for this video Mr. Billings!

    Reply
  169. Luke

    Science live is so interesting!!!!!!!!

    Reply
  170. Tripp

    I can’t believe how small DNA is.

    Reply
  171. Arianna

    I never knew what WD-40 stood for, or how it was invented. That’s so interesting.

    Reply
  172. Lily

    That’s so cool to learn about how WD-40 was created!

    Reply
  173. Zara

    I love Acellus!

    Reply
  174. Eriksen

    DNA for storage? Wow that’s certainly something. With that kind of storage I can collect memes ‘till my heart’s content.

    Reply
  175. Maddison

    I love the WD 40 story!!

    Reply

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