The Relay

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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6,345 Comments

  1. Josiah

    It’s so awesome how much logic that we learned from relays that we can apply to other aspects of systems/functions.

    Reply
  2. Austin

    the thing about wd40 was cool

    Reply
  3. Kennedy

    my dad’s a plumber, and my grand father was a pipe fitter. Its hilarious to see so many uses to WD40. Who decided it was normal to use WD40 on the gum on there shou! lol

    Reply
  4. Addison

    Using DNA for storage is very interesting and it is also a great idea.

    Reply
  5. Samantha

    That was interesting.

    Reply
  6. Ellie

    I love science live!! Thank you, Dr. Billings!

    Reply
  7. Skylar

    This is really cool! Thank you

    Reply
  8. Gracelyn

    I loved
    Dr Johns part.

    Reply
  9. Allison

    WOAH! I didn’t know that NASA uses WD40 that’s super cool?!?!

    Reply
  10. Christian

    I knew Wd 40 was a water displacement formula, but I didn’t know it was formulated for NASA.

    Reply
  11. Dana

    I am very grateful to learn brand new things!

    Reply
  12. Evelyn

    Great science live !!!!!!

    Reply
  13. Olivia

    Very good lesson thank you

    Reply
  14. Fayth

    The electronic topics you teach are very interesting, especially when you show examples with everyday items.

    Reply
  15. Lydia

    i didnt know nasa uses WD40 its really cool thats they cant find anything better

    Reply
  16. Grace

    So grateful to learn something new.

    Reply
  17. Brooklyn

    Grateful to be learning new things every wednesday !

    Reply
  18. Freya

    very cool live I love learning all of these new things!

    Reply
  19. Razam

    So grateful to be learning new things!

    Reply
  20. Kenton

    Electric bells are cool!

    Reply
  21. Annabella

    Wow! this is really interesting!

    Reply
  22. Maja

    So crazy that nasa uses WD40

    Reply
  23. Damian

    Woolly Mammoth DNA! What are the scientist going to do with that?

    Reply
  24. Julia

    Super awesome live today!!!

    Reply
  25. Alayna

    I really didn’t know you could use WD40 for so many things!

    Reply
  26. Joe

    I enjoyed this video a lot thank you!!!

    Reply
  27. Jonah

    The experiment with the lighter’s radiowaves and electricity was very interesting to see.

    Reply
  28. Brooklyn

    I’ve learned so much from science live

    Reply
  29. Conner

    I lliked how dr John explained how we use human dna to make storage on a devic and when dr billings used electrical signals to make the spoons collide

    Reply
  30. Lacey

    im so grateful for this program!

    Reply
  31. Jacob

    Science live is cool.

    Reply
  32. Amabel

    Great to learn about electricity and circuits

    Reply
  33. Zoey

    So WD40 was originally used on rockets ?

    Reply
  34. Kayleigh

    I like what had to say about the relay.

    Reply
  35. Sophie

    I am so excited for acellus world!

    Reply
  36. Chloe

    Technology is so cool!!

    Reply
  37. Jayla

    very interesting !I love this school

    Reply
  38. Saxon

    Hello from Hampstead

    Reply
  39. Benjamin

    I use WD-40 all the time; It’s kind of funny that NASA uses it too.

    Reply
  40. Cameron

    Hey Dr. Billings hope your doing well, I’m so exited to watch this episode.

    Reply
  41. Angela

    This is so interesting. I always learn something new!

    Reply
  42. Ava

    Would the liquid change the conduction.

    Reply
  43. Deklan

    I like space can that be the next episode about space

    Reply
  44. London

    Thank you for the Science Live this week! I really enjoyed learning about DNA being used for storage.

    Reply
  45. Zachary

    Love how we are taking inspiration from God’s design to create these new storage inventions! It reminds much of how we took inspiration from the design of a whale to make the first submarine.

    Reply
  46. Holden

    thanks for science live videos!

    Reply
  47. Zane

    Love to watch these.

    Reply
  48. Justin

    so glad im learning all this cool stuff

    Reply
  49. Valeria

    so cool that NASA uses WD40!

    Reply
  50. Emerson

    I’m grateful for this opportunity to learn new things

    Reply
  51. Zane

    Science live is always fun!

    Reply
  52. Avery

    I loved the part about WD40!!

    Reply
  53. James

    The first thing I think of when it comes to the word relay is “race,” though I’m sure you’re talking about a component.

    Reply
  54. Jacob

    Outstanding episode Dr. Billings!

    Reply
  55. Grayson

    Comment* Nasa loves that WD-40. I wonder what else they use.

    Reply
  56. Madelaine

    Wow this one was the most interesting so far!!

    Reply
  57. Sophia

    I love what Mr. Billings had to say about the topic for this week.

    Reply
  58. Koral

    So interesting about the WD-40. I might need to use it on my Legos !

    Reply
  59. Phoebe

    I am beyond thankful for the learning opportunities the Acellus team presents to us each week!

    Reply
  60. Ryder

    Only one more science live till christmas

    Reply
  61. Shreyak

    Wow! I didn’t know all of this about WD40. This is amazing!

    Reply
  62. Grace

    To Dr. Paget Monet:

    is there a certain person that was not apart of your life, that you looked up to, and inspired you?

    Reply
  63. Kaitlyn

    I love Science Live!

    Reply
  64. Nicholas

    Storing data in DNA is great, especially if it’s important and needs to last a very long time, the only immediate downside I see is it can’t be read quickly.

    Reply
  65. Hannah

    I thought it was great that Marconi didn’t give up.

    Reply
  66. Charles

    DNA storage is cool

    Reply
  67. Atlas

    That is so interesting about the relay!

    Reply
  68. Madeline

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

    Reply
  69. Hendrix

    Hello from VA!

    Reply
  70. Nicholas

    grateful to be learning new things!

    Reply
  71. John

    It’s pretty cool that DNA can last so long compared to other forms of storage.

    Reply
  72. Kevin

    Science live is awesome! The best part is learning something new!

    Reply
  73. Ethan

    R51 one always gives me a laugh

    Reply
  74. Gavin

    WD-40 is so universal!

    Reply
  75. Allison

    love to watch every week!

    Reply
  76. Olivia

    I think it’s so wonderful that Acellus hosts commencement ceremonies to celebrate graduates!

    Reply
  77. Finley

    I really enjoyed this live. Thank you for all you do for us!!!

    Reply
  78. Kesun

    Keep trying to come up with a solution even if it takes a lot of tries

    Reply
  79. Ethan

    I’ve used relays before is some of my electronics projects, pretty cool.

    Reply
  80. Callie

    I liked watching Dr. Billings do the experiment. I liked his drawings and how explained it .

    Reply
  81. Cambry

    Can relays get tired if they keep turning things on and off all day?

    Reply
  82. Dixie

    That was so cool! Thank you Dr. Billings!

    Reply
  83. Isabella

    The WD40 is something so interesting to learn about, Thank you for sharing that information!

    Reply
  84. Samuel

    All the planets in our solar systems are named after Roman gods, but exoplanets are named with letters and numbers. How do scientists come up with these names?

    Reply
  85. Penny

    Learning about advances in data technology was so interesting, I’d never imagined data would be stored on cassette tapes!

    Reply
  86. Hunter

    It’s so amazing how much DNA our cells store. Especially with how many cells we have in our bodies.

    Reply
  87. Logan

    That was cool i loved learning new things

    Reply
  88. Ethan

    I learned all about radio waves.

    Reply
  89. Mckayla

    My dad used WD 40 all the time. It was nice to learn a little about it.

    Reply
  90. Daniel

    Storing data in DNA is incredibly fascinating, and I hope to see further advancements/implementations of DNA storage in the near future!

    Reply
  91. Arabella

    That was so cool! I love Science live

    Reply
  92. Aiden

    The WD-40 story is very interesting!

    Reply
  93. Ramses

    I want some WD40. It sounds awesome.

    Reply
  94. Trista

    Does the storage that dr john talked about use more energy since it’s more dense? What is the environmental impact?

    Reply
  95. London

    I love Acellus and all the fun things I get to learn!

    Reply
  96. Alexa

    Being able to turn data into DNA and storing for thousands of years is super cool! There are so many different ways it could be used and it seems like something that could really help with such a wide variety of things.

    Reply
  97. Khloe

    Another GREAT video! It was so interesting.

    Reply
  98. Kenan

    What unit comes after Petabyte?

    Reply
  99. Lucas

    I liked hearing about the Rocket Chemical Company. It’s crazy it took 40 trials before they found the right coating- but it’s really cool that it only took that many times too.

    Reply
  100. Krista

    i did not know that about the WD40!!

    Reply
  101. Chad

    I never knew that’s how metal rusts. Really cool.

    Reply
  102. Allie

    The thing about Gigabites. and terrabites was new for me I did not know there was that much in our phones

    Reply
  103. Bret

    Love learning new things.

    Reply
  104. Alexander

    How many other earth like planets do you think there are?

    Reply
  105. Jonathan

    I love watching science live, it makes learning fun

    Reply
  106. Camden

    I learned how electricity travels.

    Reply
  107. Jaedyn

    Thanks for another informative episode!

    Reply
  108. Nathan

    Trully a great show!

    Reply
  109. Elaina

    WD40 is so cool!!!

    Reply
  110. Macaydon

    my father is an electrician so i was wondering are you an electrician also

    Reply
  111. Abigail

    Awesome video today! 🙂

    Reply
  112. Bethany

    I like the DNA cassette tapes.

    Reply
  113. Ryleigh

    this was very interesting to learn

    Reply
  114. Mia

    Merry Christmas science live!

    Reply
  115. Lia

    I love watching these because they are always interesting and entertaining at the same time!

    Reply
  116. Nadia

    its amazing what you can do with water

    Reply
  117. Lucia

    This science live was great it really made my day!

    Reply
  118. Jayce

    I like how it’s diffrent every time

    Reply
  119. Zendnaida

    This is so educational!

    Reply
  120. Seth

    DNA being used as storage is a pretty interesting application!

    Reply
  121. Daniel

    Storing data in DNA is incredibly fascinating, and I hope to see further advancements/implementation of DNA storage in the future.

    Reply
  122. Lily

    does it go any higher than PB? I thought the highest was TB

    Reply
  123. Gina

    I found it very interesting that WD40 has such a history. I’ve always thought it’s only purpose was to was to grease/lubricate squeaky hinges and bolts. I will have to test it for it’s other uses/purposes!

    Reply
  124. Olivia

    It was interesting learning about WD40

    Reply
  125. Maxamus

    i like learning about dna

    Reply
  126. Joaquin

    Hi from Delaware!

    Reply
  127. Zian

    Happy Holidays!!!

    Reply
  128. Elijah

    Really cool about the WD-40. I didn’t know that.

    Reply
  129. Addison

    I love science live so much and I hope yall have a wonderful Christmas

    Reply
  130. Autumn

    So grateful to be learning new things!

    Reply
    • Lauren

      Have a merry Christmas !

      Reply
    • Ahdan

      IVE NEVER SEEN THIS BEFORE

      Reply
    • Ava

      I’m truly thankful for Acellus and Science Live.

      Reply
    • Kadean

      I love science live.

      Reply
    • Esther

      Thank you Dr. Billings!

      Reply
    • Bronson

      Lady Pajet’s laugh is the best!

      Reply
    • Dayana

      Thank you dr. Billings! 🙂 happy to learn new things

      Reply
    • Travis

      it’s cool you can use dna for data storage(:

      Reply
    • Ariyana

      So appreciative that I am able to be here!

      Reply
    • Morgan

      Thanks so much for the effort put into this weeks episode and all the others.
      Have a great week!

      Reply
    • Mckenna

      Hello from Colorado

      Reply
    • Yaar

      Interesting fact about WD40!!

      Reply
    • Curtis

      I love Science Live! its the best!!!

      Reply
    • Peyton

      Just like Thomas Edison— Acellus is fun, it’s not doing work!

      Reply
    • Kamden

      How does the electromagnet in an old electric bell cause the hammer to strike the bell repeatedly?

      Reply
    • Angel

      Thank you very much

      Reply
    • Aubrey

      Loved this episode!

      Reply
  131. Lucas

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

    Reply
    • Lydia

      I really enjoyed this science show. I learned a lot!!!

      Reply
    • Katelynn

      I thought the part about WD40 was so cool.

      Reply
  132. Joshua

    That’s funny that’s NASA uses WD40.

    Reply
    • Benjamin

      This lecture are always amazing.

      Reply
    • Elizabeth

      Is it possible to find a new planet in the future?

      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
    • Gabriella

      It’s exciting to learn about different planets and other things in the universe

      Reply
    • Christian

      WD40 is honestly so impressive using radiowaves to conduct electricity.

      Reply
    • Lily

      Another amazing science live!

      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
    • Addalyn

      ya he did that is so funny

      Reply
    • Samaira

      Wd40 is a staple in my grandparents house it’s used more than anything

      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
    • Neli

      Acellus World look’s like fun!

      Reply
  137. Kaydence

    it’s so crazy that nasa uses wd 40

    Reply
    • Maegan

      I didn’t know that the NASA uses wd40 that so cool my dad always uses it for work.

      Reply
    • Avyn

      Dehydrated dna is interesting

      Reply
  138. Arya

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

    Reply
    • James

      I think you just need to pass and finish all of your subjects

      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
    • Baris

      It’s astonishing how small inventions can become so vital even in projects that are a lot more complex.

      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
    • Eden

      We use WD40 at home!

      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
    • William

      😂

      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
    • Avery

      I never knew that about WD40!!!

      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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