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 »
Everyone who wore a tie in the first thirty minutes of this had to have coordinated to wear the same or similar color of tie, lol.
We have an old door bell, it has the same mechanical concepts
Hello, from Nevada. How would the bell reset?
Hello from Missouri, I love Acellus!!
my great grandfather was in WW2 so he taught me and my other grandkids aviht Morse code!!
Does the electricity cause different noises depending on what it goes through and how thick it is?
Hi from Texas! I love watching these science lives, they’re very interesting!
This is so cool
Checking in from Vermont! Thank you for everything!
Dit Doh Dit Doh
Hello from Idaho!
Great show
I love science live!
This one was very interesting I love learning about new things
Yay! Science live!
could I be able to make a electric bell in my home?
Hello from New Mexico
Interesting show tonight
It’s crazy about buzzers that they can buzz for a long time.
I like Lady pajet’s outfit! also i’m sorry if I spelt it wrong!
I really wanna learn morse code
hellooo from missouri
Wow!!! Area 51….
TY
that’s very interesting. Who would have ever thought every single bell had that much science behind each ring. 🙂
I have used WD40!! So interesting!
What is the central component wrapped in copper wire?
Would This Coherher used to detect small Earthquakes? Because small earthquakes happen almost every day!!! And there sometimes too small to be detected except by Seismograph! :]
Yay
The info about the bell was very interesting!
What would happen if you tried to send a long buzz and a short buzz at the same side on opposite ends of the line
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how do they make a spark last longer?
I love Science Live!!
that is so intresting that it took then 40 time to get the right equation to make it.
Why is copper wire used a lot in inventions? Is it better wire?
I wonder what is in WD-40?
My grandpa taught me about Morse code
Amazing show tonight!!!
how much money did they make selling the WD-40?
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how much force does the electricity need to make in order to make contact between the spoons
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I liked hearing about WD-40 .
Morse code will never fail to amaze me
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I’m Caiden from Louisiana
hello from Mississippi
Can we get a tour of Acellus HQ?
I think your WD40 discussion is so fascinating!
Why did the rocket paint take 40 tries from letting water go inside of the paint. Michael.D
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WD-40 story is cool
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Merry Christmas from Hawaii.
1838 you weren’t a live
Comment this is cool! *
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hello from ND
You can’t say school without saying cool!
hi from ND
Hello from Montana
Hiiii
Hi Will from Georgia.
I learned that WD-40 Can make it easier to take apart LEGOS.
Great info! Science Live is awesome
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Dr. Roger has so many interesting things to say today. Thank you.
Thanks for Science Live! Hello from Vermont!
How long did it take Joseph Henry to invent the bell alarm?
how was morse code invented? :]
Hello from Montana
The part about we 40 was really cool
Science live is awesome!
I may have to get wd 40 to get my Legos unstuck.
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Very interesting about WD-40. The kind of stuff dreams are made of.
Honestly, Science Live is amazing. 🙂
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Hello from Illinois 🖤 🩶
Can’t wait to watch!!! *
Watching from Texas! I freaking love you guys
wow that is so cool how he made it ring over and over
I love science live
And Roger Billings.
Could using WD-40 damage Legos that you have stuck together?
ha ha ha ha
I use WD-40 all time it’s amazing, and hi from Wyoming.
Is this what they use for school bells? If not they should it’s smart
That’s cool
Hi from America
Was that how they made some school bells?
wow
Hello, from Nevada! What prompted Joseph Henry to make this contraption.
I love science live so much!!
WD-40 Fixes everything!
It is so cool learning about the first bell and how it was made!
Phenomenal ScienceLIVE like always!!
Hello from Texas
this is such a good live so far
Hello
Science live is amazing
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hello people
hi
I wonder if the next evolution of storage will use atoms or even particles.
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Love Science live!!
I love science live I’m watching it watch ALL NIGHT!!! HOMESCHOOL POWER GOOOOOOOOO!!
What makes WD-40 so versitile?
Science live is my favorite!
Hi from Texas! Love this show!
That’s a really cool invention!
WOW! This is so cool.
HI YALL
Hey from Texas 🤠
What is the central component wrapped in copper wire, and what is its general function in an electrical circuit?
what else did Josef henry invent?
checking in!
I love science live!
Hi from Michigan
Yeah! Science!
Cool 😎😎😎😎😎😎😎
I didn’t know wd-40 was made from Nasa
Comment This live was extremely fundemental!
I enjoy watching experiments on science live
I made my own alarm that goes off if someone opens the door! I love learning about electrical engineering!
I love science live!
I love science live so much!
This is so cool.
Good evening to you!
Learning about the electric bell was my favorite part.
It was fun to learn about the WD-40. It was really really fun. I am glad this was hosted!
The way the bell works is to interesting!
Can’t wait to see R-51!
Hi from Montana
I love this
Nothing better.
WD-40 is so interesting!
I love learning about radio waves and stuff like it!! It’s always so cool!!
Is this magnetic bell used for alarm clocks? It looks pretty similar to one.
hi from virginia.
Does the light bulb go on forever until the radio wave is interrupted?
Happy Holidays everyone from Northern California. Always keep WD40 handy!!
Wow acellus world looks so fun!
Electromagnetism has pretty impressive applications. Dr. B., is this part of the reason certain plants and mushrooms can “sing” when hooked up to a certain device?
Hey from New Brunswick!
Hi from Michigan
Hello from Kentucky. Today I ask what is the science behind electricity and how it power’s things?
I enjoy Dr.Pajet Monet’s classes, it’s great to see her here!
Watching from Nevada!
It was really cool to hear how WD-40 was made and that it was first used for NASA but ended up being used for over 2000 different things. This is my first science live and definitely worth watching.
hello from Bangladesh
I have never heard of a transistor, but it’s crazy how they are in all of our technology we use every day. I would enjoy learning more about them.
My grandpa uses WD-401
One thing I didn’t know was that u can use w-d40 to unstick Legos.
Hi from Las Vegas! I love science live!
Oh boy how I enjoy science Live. Transistors are so interesting.
I have always wondered how currents work, both types, water and electrical currents!
Science live is so fun! Thanks for doing it every Wednesday.
My grandfather was replacing a tube in a TV and accidently touched a capacitor and got blasted and knocked out. He dropped the tube and broke it, too. That is neat how the cohesive thing works…
I love space! Maybe one day i can work for NASA!!
Try, Try, again!!
My Dad always has WD-40 in the garage, time to cause some science! Muhahaha!!!
Nice fact about DNA is becoming a new storage technique.
Hi from NC Willard.
I love R51
I had no idea WD-40 had so many uses and I love the backstory 🩵!
To: dr. Roger
Has there ever been a time where you wanted to give up on one of your experiments?
Happy Wednesday
Hi from Baltimore
What happens if you touch the AL foil balls while there is a radio wave?
WD-40 is a very useful invention.
I love science live!
That’s awesome my dad and me Have a collection of fire alarms that we power ourselves…
Learning more about the aluminuim and fire was really cool I enjoyed it a lot, It was very interesting to learn about how it all works in both videos.
WAS NASA EXCITED FOR THE WD-40
area 51 is my favorite