A toaster is an example of a home appliance that produces heat when electricity flows through them. A toaster is made up of a large metal box (the housing of the toaster), a lever, and two heating elements (Chris, 2021). A toaster is activated by using the lever which pushes two pieces of bread down against the heating elements, cooking them until desired doneness is reached. The front side of a toaster has a small metal door where users insert bread slices. The heating elements are positioned between this door and another on the opposite end which covers more of the space within the toast
How a Toaster Works
When switched on, electrical energy flows from a domestic electricity supply into the toaster. The bread is inserted into a toaster and the current is sent through its metallic heating element. The heat produced travels up the element and is evenly distributed throughout the appliance by conduction. After coming in contact with the metal wire heating elements, electricity automatically flows through them and heats up within seconds (Chris, 2021). This heat then spreads across unto the bread which in turn begins to toast it from both sides until browned.
Once the bread is in contact with the element, electricity automatically flows through them and heats up within seconds. Regardless if one uses an automatic shut-off timer or sensor, after some time, depending on how crispy they want their toast done, one can control how much they want their toast done. After coming in contact with the nichrome wire heating elements that are electrically charged, small pockets of air begin to heat up inside each metallic wire loop which then eventually spreads away from itself into what appears as flames within seconds. Figure 1 below shows the nichrome wire in a toaster is a resistance wire with a high temperature coefficient of resistance. It is an alloy made mainly of nickel and chromium, so called because it has similar properties to nichrome steel alloys used in heating elements. When electricity passes through the wire, it heats up due to the high electrical resistance and thus gets hot enough to toast bread by being placed within its vicinity.
Figure 1: How a Toaster Works, Source; (Baguley and McDonald, 2015).
The toaster has a control circuit that switches the power on and off so quickly that the heat generated by resistance does not cause any noticeable change in temperature of the surrounding surfaces (Chris, 2021). It might take around 0.1 seconds for an incandescent light bulb to turn on at full power which is usually more than 1 second for lower wattage, because it takes time for the filament to get hot However, the same amount of time passes between switching on and off of an electric current flowing through most types of resistive heating element (heating wires), raising their average temperature above room temperature only very slowly (for example, one hour to heat up by 10 degrees Celsius).
During a power cycle, one or more heating elements rapidly heat up and then cool down again. In most toasters, there are at least two heating elements so that it can produce several pieces of toast at once. A toaster uses one or more heating elements (or resistance wires) to heat the metal wiring inside. This heat raises the temperature of the bread to a suitable range for toasting. The heating elements can be electric filament wire, resistance wire or metallic ribbon.
In summation, toasters convert energy in electrical form into heat through electric current flowing through its metal wire heating elements that come into contact with bread. Electricity automatically flows through them and heats up within seconds. Once the metal wire heating element comes into contact with bread, it transfers heat onto the bread which then begins to toast it from both sides until browned.
Baguley, R., & McDonald, C. (2015, February 2). Appliance Science: The well–done physics and chemistry of the toaster.
Chris, W. (2021). Electric toasters. Available at: https://www.explainthatstuff.com/electrictoasters.html