Conduction. Resistance. Radiation. And how alloys are used in cooking.
1-Minute NomNom
A piece of bread is toasted when it absorbs the heat from a heat source. The heat can come from many sources, e.g. a grill, an open fire, a toaster.
In a toaster, it comes from a heating filament. You can see this heating filament: It is the wires that glow red-hot when you look into a toaster as it is in use. This filament provides resistance to the flow of electricity, thus making the filament hot, radiating heat toward the bread.
As resistance is key to the whole phenomenon, it is important to pick the right materials for the filament. That is why nichrome (NiCr) – an alloy of nickel (Ni) and chromium (Cr) – is often used to make the filament.
Unlike metals which typically conduct electricity well, alloys do not (a mis-conductor :P?). The chemical structure formed by the two chemical elements impede electrons, making it harder for the electricity to pass through. In addition, nichrome in particular has the quality of being able to withstand repeated heating without melting or breaking.
Second Helpings
When you are using your toaster (or immediately after), you should never touch the nichrome filaments, for the same reasons that you would never touch a red-hot fire or red-hot coals. Their temperatures can be anything from 500°C/932°F to 1200°C/2192°F! Keeping us safe is also why designers made the bread pop out of the toaster when our toast is ready.
Feed Me!
What other examples can you think of where accidents have been designed out of household appliances? Share your thoughts with me!
Like this? Be my alloy-bi and like me to discover more. All you need is a minute a day to explore the world’s marvels through the phenomenon of food!
photos: in order – SpeedliteModifier/istockphoto; nglyeyee/depositphotos
