Heat Transfer: Conductors and Insulators

Depending on which way you want energy to transfer, there are many materials that CONDUCT energy and many materials that INSULATE energy. 

Heat loves to travel and it will go from hot to cold every single time.  We know that metals are really good at helping energy travel through and around it.  But what kinds of materials keep energy from entering or leaving?

Energy has trouble getting past wood, glass, cork, cloth, and plastic to name a few.  Why is this true?

We know that energy can travel by conduction...so why can't it conduct its way through glass, or wood?  

Insulators usually have pockets of air, some pockets are really small, but it's just enough that the energy can't jump or travel very well through it.  

Fiberglass is a great insulator, we see this material on lots of kitchen appliances, bathtubs and boats.  

...and fake nails?  Fiberglass looks like spun glass, it's strong when wrapped all around like a spider web and it is full of little air spaces.  This makes it a great insulator!

Watch how fiberglass is made, this is totally satisfying!  And you will be satisfied to know that your home is insulated well enough that you can the heat in during winter!  Thanks to INSULATORS!