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. Laya

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

    Reply
  2. Malaysia

    Every Science live I watch teaches me something new.

    Reply
  3. G

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

    Reply
  4. Henry

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

    Reply
  5. 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
  6. Malayna

    This was very well explained.

    Reply
  7. Brandon

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

    Reply
  8. 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
  9. 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
  10. Amy

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

    Reply
  11. Julia

    I like the Science live videos!

    Reply
  12. Layan

    I LOVE SCIENCE LIVE

    Reply
  13. 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
  14. Liliana

    I enjoyed this video a lot and very well explained.

    Reply
  15. Matteo

    I never knew that NASA used WD40!!

    Reply
  16. 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
  17. Nadhia

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

    Reply
  18. 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
  19. Eden

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

    Reply
  20. Natalie

    Circuits are so interesting.

    Reply
  21. Grayson

    Thanks for the science live! love learning new things.

    Reply
  22. 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
  23. Karah

    That was so cool!!!!

    Reply
  24. Jesius

    DR. Billings you are amazing!

    Reply
  25. Khloe

    i love how much science lives have taught me

    Reply
  26. Harry

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

    Reply
  27. Makenzie

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

    Reply
  28. 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
  29. 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
  30. 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
  31. Jaden

    i didn’t know that about WD40

    Reply
  32. Henry

    R-51 Have an electro shot! 😂😂😂😂😂

    Reply
  33. Arabella

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

    Reply
  34. Riley

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

    Reply
  35. Audrey

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

    Reply
  36. Liam

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

    Reply
  37. Anthony

    i would love to learn about WD-40

    Reply
  38. Phoenix

    I am so grateful for the science lives!

    Reply
  39. Darby

    I love science live!

    Reply
  40. Vincent

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

    Reply
  41. Ella

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

    Reply
  42. Elisa

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

    Reply
  43. Antonio

    We love Dr. Billings

    Reply
  44. Dashiell

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

    Reply
  45. Aislynn

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

    Reply
  46. Nathan

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

    Reply
  47. Sydney

    WD-40 is so versatile

    Reply
  48. Kerrington

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

    Reply
  49. Jaxon

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

    Reply
  50. Caleb

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

    Reply
  51. Amelia

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

    Reply
  52. Jovi

    I am enjoying learning new things from Science Live!

    Reply
  53. 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
  54. Jude

    Thank you Dr. Billings for Science Live.

    Reply
  55. Joshua

    Wd40 literally fixing everything

    Reply
  56. 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
  57. Miyuki

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

    Reply
  58. Dakota

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

    Reply
  59. 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
  60. Victoria

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

    Reply
  61. Emily

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

    Reply
  62. Lillian

    This is one of my favorite science lives!

    Reply
  63. 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
  64. Faith

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

    Reply
  65. Kalea

    R-51 is the best part!

    Reply
  66. 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
  67. Opal

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

    Reply
  68. Forest

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

    Reply
  69. Jadyn

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

    Reply
  70. Ridley

    Is R-51 ok?

    Reply
  71. Maverick

    I am so thankful for electronics.

    Reply
  72. Mercedes

    I want to make a relay for a science project!

    Reply
  73. Jeremy

    Electricity has always facinated me.

    Reply
  74. Rylee

    How do you measure the speed in a relay experiment

    Reply
  75. Chloe

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

    Reply
  76. Jaxon

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

    Reply
  77. Juliet

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

    Reply
  78. Aubrey

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

    Reply
  79. Giovanni

    What is the difference between a relay and a transistor?

    Reply
  80. Abygail

    My dad used WD40 all the time

    Reply
  81. Juliet

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

    Reply
  82. Gip

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

    Reply
  83. Anthony

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

    Reply
  84. Will

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

    Reply
  85. 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
  86. 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
  87. Blake

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

    Reply
  88. Connner

    Awesome video, thank you for teaching me new things

    Reply
  89. Hannah

    Hey from Oklahoma!

    Reply
  90. Travis

    I love r-51

    Reply
  91. Hana

    Can 4th Grade Students go to acellus world.

    Reply
  92. 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
  93. Kimber

    Science live is so intriguing and fun!

    Reply
  94. Olivia

    im so grateful for this class!!

    Reply
  95. 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
  96. Huet

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

    Reply
  97. Cayley

    I never knew about WD40, that was so interesting!

    Reply
  98. Salem

    Dr.Billings is so smart!

    Reply
  99. Hudson

    I love acellus!

    Reply
  100. Mackenzie

    The new acellus convention center looks very cool

    Reply
  101. Magdalena

    Watching from Georgia!

    Reply
  102. 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
  103. Lillian

    The story behind how WD 40 was made is crazy.

    Reply
  104. Justin

    I liked learning about the relay

    Reply
  105. 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
  106. Braelyn

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

    Reply
  107. Sergio

    I love all the ways there are to use WD40.

    Reply
  108. Gage

    If I do ever invent something, I am going to NOT give up. I just won’t be able to. But, I’m not good at being creative and thinking of new ideas.

    Reply
  109. Cody

    I like watching science live, it’s enjoyable!

    Reply
  110. Gabe

    Wow I didn’t know how useful WD40 is.

    Reply
  111. Addison

    R51 is the best part of science live

    Reply
  112. Slade

    I love WD40. Merry Christmas to everyone

    Reply
  113. Silas

    i love learning about this

    Reply
  114. Faye

    How reliable are cassette tapes compared to the memory of our phones and computers?

    Reply
  115. Conrad

    That is so cool about WD-40, my dad uses it all the time

    Reply
  116. Dakoda

    R51 used organic grounding

    Reply
  117. Ayesha

    Thank you so much for helping us learn new things!

    Reply
  118. Samue

    I love watching this and learning new things thank you guys so much!!!!!!

    Reply
  119. Makayla

    WD40 is interesting. It has so many uses.

    Reply
  120. Skylar

    Helloo! sorry i forgot to watch it last week i was in vacation, but i love watching the science live videos!!

    Reply
  121. Nora

    NASA uses wd40? I didn’t know that.

    Reply
  122. Lillian

    I love Science Live!!!

    Reply
  123. Daniel

    Science live is great

    Reply
  124. Enoch

    ohhh this might be my favorite episode! I love science live!

    Reply
  125. Ellie

    Learned many new things today! I love I’m able to!

    Reply
  126. Frankie

    I have a circuit set at home that this reminds me of.

    Reply
  127. Carter

    My dad was in the navy and much like
    NASA using WD40, my dad used duct tape to fix everything!

    Reply
  128. Xavier

    I have some snap circuits that have a relay.

    Reply
  129. Aviana

    I love how many uses there are for WD40! I wonder what other simple tricks NASA uses day to day.

    Reply
  130. Garon

    I liked hearing about DNA I would love to learn more about it.

    Reply
  131. Nadhia

    I LOVE SCIENCE L!VE!!!!!!!!!!!!

    Reply
  132. Alena

    how long is dna stored for?

    Reply
  133. Olivia

    I wonder how much technology will advance in the future

    Reply
  134. Lyla

    My great grandpa said just about anything could be fixed with WD40 and some tie-wire.

    Reply
  135. Lexi

    the key stone holds the arch together

    Reply
  136. Jozette

    Checking in from CA!

    Reply
  137. Penelope

    its so amazing how things are invented/inspired by other creations! Science really is in everything

    Reply
  138. Kynlie

    I love watching science live

    Reply
  139. Zachary

    I enjoy watching these videos.

    Reply
  140. Trinity

    I loved this lesson it was explained so well

    Reply
  141. Gage

    This is the best part about school!

    Reply
  142. Steven

    I love the videos they teach me so many things.

    Reply
  143. Jaylen

    I Didn’t know that nasa uses WD40

    Reply
  144. Caden

    I love science live!

    Reply
  145. Rio

    I really like the things you do on science live. Like the invention to make the bells ring.

    Reply
  146. Briella

    That was so cool learning about WD40

    Reply
  147. Evelyn

    i enjoyed this video very much!!

    Reply
  148. Mckinzie

    I always learn something new on science live.

    Reply
  149. Kayleece

    I would’ve never guessed that NASA uses WD40.

    Reply
  150. Jenna

    Enjoyed learning about new types of data storage.

    Reply
  151. Brook

    Hello from Kentucky! I really enjoyed the episode!

    Reply
  152. Edward

    I never knew wd40 was made for that and what other uses can you use it for?

    Reply
  153. Carlos

    Wd40 can be used for so many things!

    Reply
  154. Von

    How do you make your own website or school like this one and do you have to code the entire thing to work?

    Reply
  155. Chandler

    How does Dr. Billings decide what inventions he is going to teach about?

    Reply
  156. Kayleigh

    Hello from South Carolina

    Reply
  157. Jo

    Hi from Kansas City, Mo. Merry Christmas.

    Reply
  158. Tamia

    I’m so grateful for Science Live!

    Reply
  159. Izzibell

    I find it really fascinating how the radio wave can activate the bell and the light!

    Reply
  160. Aiden

    Has nasa ever sent a telescope far out into space?

    Reply
  161. Gavin

    Thank you for this science live i learned so much!

    Reply
  162. Jakiyah

    It’s insane that nasa uses wd40

    Reply
  163. Olivia

    Its pretty cool that nasa uses wd-40, and it’s interesting to know all the ways it can be used.

    Reply
  164. Isaiah

    How did the shape of dna come to be?

    Reply
  165. Johanna

    I think electricity is very interesting !!

    Reply
  166. Solomon

    Pretty smart using another re-occurring signal for the bell.

    Reply
  167. Brendan

    Thank you Dr Billings for another great Science class

    Reply
  168. Gabriel

    Funny r-51 I love watching science live, it is so interesting.

    Reply
  169. Anya

    This video was very interesting. I always wondered how it was possible for them to keep water out rockets because there are lots of gaps between each piece of the rocket.

    Reply
  170. Ava

    Wow WD40 is super fascinating! I love learning new things on Science Live!

    Reply
  171. Jayden

    Were there NO other rust removers before wd-40?

    Reply
  172. Etta

    Did everybody noticed the robot at Acellus world?

    Reply
  173. Edahlia

    Thank you Dr.Billings for this video!

    Reply
  174. Ronon

    I agree with Dr. Roger Bilings that R51 is a conductor.

    Reply
  175. Liam

    Its amazing how much DNA can be put in that tiny capsule and saved for so long.

    Reply

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