You pop a delectable, sweet M&M® into your mouth. It melts and you crunch down on the sweet shell around it. Why didn't it melt into your hands when you were holding it?
We know that melting point is defined as the temperature at which a solid changes state to a liquid. The melting point of some metals is higher than others, which means that they melt at different temperatures. For example, mercury has a melting point of -37.95 degrees Fahrenheit while iron has a melting point of 2700 degrees Fahrenheit. Because mercury’s melting point is so low, it is rarely found as a solid (because you would have to go to somewhere that is colder than -37.95 °F). Because iron’s melting point is so high, it is rarely found as a liquid (because you would have to heat it up a lot).
When we’re dealing with mixtures and not pure elements like iron and mercury, things are much more complicated. A mixture won’t have a single melting point but a melting range because each individual ingredient has a different melting point. The melting point of chocolate, for example, is between 61 and 99 °F. So why doesn’t the M&M melt in your hand? Take a look at the data below.
|Temperature of average human’s palm:||between 90 and 95 °F|
|Temperature of average human’s mouth:||about 99 °F|
|Melting point of chocolate:||between 61 and 99 °F|
- Based off of the above data, would chocolate technically melt on your hands,too? (Hint- Look at melting point values)
- In terms of chocolate, it is very difficult to ensure that every single M&M has the same melting point. What could be another factor that keeps the M&M from melting? (Hint- Think of the structure of the M&M)
- What would happen if you removed that barrier? (Hint- Melting point!)