A common question that people have is does hot glass look the same as cold glass? Is there a difference in appearance between hot and cold beakers? The answer to this question is yes. Hot and cold glass or plastic can look different.
One way to test this visually would be to place an object in the center of a cup of both hot water and cold water, then wait for it to sink below the surface before removing it from the liquid. If you are looking at both cups through a window, you should notice any bubbles coming up from the bottom will show more quickly in warm water because they expand faster than cool ones do (warm air expands faster than cooler air).
Another way to test this would be by placing a hot glass in cold water. Does the temperature of the water affect how quickly or slowly it cools? The answer is no, as long as you allow enough time for cooling off. When an object is placed into another liquid at a different temperature than its own, there will always be heat transferred from one body to another until they reach equilibrium (at which point they are both at equal temperatures).
Energy can only flow from areas where it has more concentration to areas where it has less concentration. If we place something hotter than room temperature into a container of ice, it adds more energy won’t make the ice warmer but instead melt and cause it to become colder.
A hot glass in cold water will also experience the aforementioned heat transfer and reach equilibrium. The only difference is that this process takes place more slowly because of the lower temperature of the liquid at which it’s being placed.
If an object is placed into another liquid at a different temperature than its own, there will always be heat transferred from one body to the other. The water will become hotter, and either melts or heat the glass to a higher temperature than its own before reaching equilibrium.
So does hot glass look the same as cold glass?
Nope! Actually, it looks quite different—hot glasses have foggy condensation on them while cold glasses don’t have any visible moisture on their exterior surfaces (though they can still be just as wet). The hotness is measured in degrees Celsius, so when you reach temperatures above the boiling point of 100°C your body has reached fever levels; whereas if you’re below that threshold, somebody would say that your body is cool. Coldness is also not a measure by itself but instead could mean being at or below freezing (0°C) or being at or below the boiling point of 100°C.
In a hot glass experiment, you will see condensation on your beaker that’s not visible on cold glasses. This is because as soon as the water reaches equilibrium with warmer temperature (as in higher than its own), it releases heat and cools down. The foggy vaporization process slows when this happens meaning there isn’t any moisture to release onto the surface of the glass.
This means that if we place our hot glass into cold water, it can stay intact without breaking due to extreme thermal contraction and expansion: so does hot glass look the same as cold? Nope! Hot glass looks different than anything else; which makes for an even better science experiment.
What’s the first thing you notice when pouring a hot liquid into cold water? If you’re like me, your instinct is to avoid spilling by using two hands at once: one hand holding the cup and another controlling its tilt until it meets with an equal amount of water in a container on the other side.
This happens because as soon as we mix these two liquids, they form what’s known as “an exothermic reaction.” This translates to heat being released from that very instant; which means if the temperature difference between our glass and the surrounding environment was large enough before mixing (say for example -20°C), then there would be extreme thermal contraction and expansion immediately after contact with all things outside of equilibrium.