♪ [upbeat music]
(Melissa Radey) Hi. My name is Melissa.
I'm a staff scientist here at Science North and this is my pal Sheepy.
We are super excited to talk to you today
about some great and relevant science
that has been happening around the Science Center
along with our green initiatives.
So since we're talking about bulbs, you may have guessed,
how about we turn over and do a bit of science?
So an incandescent bulb works basically just like a giant resister.
So this filament here resists some of the flow of electricity
so that the electrons --
you imagine little electrons flowing through the circuit--
the electrons have to work really hard to get through the resister.
And that creates heat.
The harder the electrons work,
the more heat that they're producing
and then the more work that they have to do
in order to combat that resistance.
What we get from that is heat.
Heat gets created.
Now, at this point is when the light starts to incandesce.
So the wording incandescent means that the filament is getting so red hot
that it's producing light.
So, we've got light coming out here.
So we've produced heat and light with our incandescent bulb.
Keep in mind that everything I explained about the electrons flowing,
all of this happens virtually instantaneously
with the flip of a switch.
You'll notice when you turn on an incandescent bulb,
that eventually it gets hot.
And herein lies the problem with it's efficiency.
It's getting hot.
You're paying for the electricity to heat the bulb
when that wasn't really your intent.
You wanted to buy electricity,
you wanted to buy electricity to turn on the light,
but you're stuck paying for all the electricity
that's heating the bulb and everything around it.
So inside an LED,
there is semiconductors.
Scientists say that these semiconductors have been doped
so that one side of it has extra electrons.
So if you imagine electrons are negatively charged,
we call this an N-type semiconductor.
The other side of the semiconductor is doped with holes.
You can imagine that it's more positively charged,
so it's called a P-type semiconductor.
All of this is to create a P-N junction.
And that is where the magic happens.
And by magic, of course, I mean science.
At the P-N junction boundary
is where the electrons and the holes can combine
with a release of energies.
So since the electrons are existing at a slightly higher energy level
than the holes, when they combine,
they release energy in the form of light
without creating any heat.
Not only do LED bulbs save on energy,
they also last about 50 times longer than traditional incandescent bulbs.
I think maybe about now it's time for us to go on an adventure.
What do you think Sheepy?
We've got some really neat LED lights on the Tunnel
that I would like to show you.
Here we are at the entrance to the Science Center,
affectionately known as the Tunnel.
You'll notice how awesome and colorful the lights are in here.
So with our switch to LEDs,
not only were we able to save a colossal 40%
on our energy operating costs for this area,
we get the opportunity to change the mood so to speak
and make the trek through the Tunnel
slightly more interesting for the visitors.
Meanwhile in the parking lot,
the new energy efficient lighting plan has allowed us to improve light levels,
reduce light pollution,
and incur a 30% savings in the energy costs associated with the area.
So the switch to LED lights
is part of a larger green initiative that we have here at Science North.
It allows us to practice being environmentally responsible
and this is something that we're highlighting for visitors.
So when you visit Science North next time,
keep an eye out for Sheepy.
He's a beacon of green in the building
who's letting us know
what sorts of things the Green Team is working on.
Alternatively, you can check us out at sciencenorth.ca/green
to see some of the other green projects
that we have coming up on the horizon.