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 »
Go Science Live!! Dr R is so great
R51 is so funny
R51 was so funny this episode.
This has truly been one of my favorite episodes so far.
These lives are always interesting and teach so much! I never knew most of these things
Dr.B made it look so fun and I’m going to go home and try it out
I love watching these Science Live it is so much fun !!!!❤️😇❤️🔥
I never knew WD40 was kinda interesting
“another fine product…” (was their only product) lmao
so what if im using wd-40 on my legoes
I didn’t know you could create radio waves with a spark.
Relays are cool!
I love science live!
Thank you for this Dr. B!!
r51 is halarious
i used WD-40 to get a coffee stain out of my table
R51 is so funny
It’s a good lesson to never give up, even if it takes 100 tries.
I use W2-40 on my bicycle!
Who knew WD40 could be that useful
DNA is very intresting, I would like to learn more
This episode was AMAZING!!!!!!
R51 is really funny
I loved R51
Watching from Chicago thank you for the wonderful episode.
What was the process of originally inventing a circuit relay?
It was interesting to learn about Wd40. my dad uses it sometimes in the garage.
There’s always something new I learn every science live!!!
R51 needs to start watchin what he says lol
R51 is so funny, he needs to be more careful!
Thank you for sharing all this great information with us!
wow interesting
loved this
I love learing about circuits and how to make them,
WD40 has so many uses! Who would have guessed!
Wow, the relay was so cool!
Poor R51, he got electrocuted!
I’ve only ever used WD40 on rust and things like that. I never really thought that much about it until this video.
We made a circuit relay at home it was so cool
Sorry that you got shocked R-51!!!!!😭😭🥺
R 51 is soooo funny
love drb he is my fav
I never knew the history behind wd-40 until now
Hello from NC!
Here from Tennessee. I love learning
I never knew how radios work but now I do! Thanks DrB.
What are more ways vacuum tubes can be used?
I didn’t know WD40 is used for so many things!
I’m getting caught back up from Christmas break! Happy New Year everyone! I love learning about new things on Science Live!
Happy New Year! R51 is so funny
Science is the best
Science live is so interesting
I like the Thomas Edison quote, “I never did a days work in my life, it was all fun”.
Using DNA for storage is amazing and should be used!
I love the way WD-40 smells
Happy New Years from Nevada! It feels great to be back
WD-40 has so many uses but I never thought about how many and the amount of cans sold everyday!!!
Do twins have the same DNA?
My dad is a mechanic so WD40 is something I have always been told is a wonder tool.
My mom was so surprised when they said what WD 40 stood for.
WD-40 is a cool thing and used for so much stuff. I’ve seen my dad use it on cars and rusty things, we use it on my bike chain, I have even seen my mom use it to get ink out of the dryer, and crayon off the walls! It’s a really cool chemical that can be used for a lot of things, but it was cool to see what else it could be used for too!
Wow, I didn’t know. DNA could be like this.
R51 is so funny! 🤣
One of my favorite R51 appearances, always the highlight of the episode!
I’ve only ever used WD40 on rust and things like that. I never really thought that much about it until this video.
I never knew that WD-40 was sold that much!
Really interesting and entertaining episode.
Science lice is definitely a highlight of my week! Learning about such cool things like, WD-40 or DNA is always so fun.
Wow I didn’t know DNA could be used like this.
I never realized how important wd 40 was. It does have a lot of uses!
I am learning so much from science live, I really enjoy it!! Thank you for breaking it down and making it easy to learn.
Gotta love R51!
I never knew just how much WD-40 was sold everyday. That’s a lot of cans!!!
science live is the best !!!
What makes a circuit close and open.