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Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an example of this property used in a consumer product although thermochromism also has more practical uses, such as baby bottles, which change to a different color when cool enough to drink, or kettles which change color when water is at ...
Similarly, color is due to the energy absorbed by the compound, when an electron transitions from the HOMO to the LUMO. Lycopene is a classic example of a compound with extensive conjugation (11 conjugated double bonds), giving rise to an intense red color (lycopene is responsible for the color of tomatoes).
Thermochromic ink (also called thermochromatic ink) is a type of dye that changes color in response to a change in temperature. [1] [2] [3] It was first used in the 1970s in novelty toys like mood rings, but has found some practical uses in things such as thermometers, product packaging, and pens. [4]
The resolution of liquid crystal sensors is in the 0.1 °C (0.2 °F) range. Disposable liquid crystal thermometers have been developed for home and medical use. For example if the thermometer is put onto someone's forehead, it will change colour depending on the temperature of the person's body. There are two stages in the liquid crystals:
Normally, the indicator causes the color of the solution to change depending on the pH. Indicators can also show change in other physical properties; for example, olfactory indicators show change in their odor. The pH value of a neutral solution is 7.0 at 25°C (standard laboratory conditions). Solutions with a pH value below 7.0 are considered ...
Oscillogram made in July 1972 by Briggs and Rauscher. The Briggs–Rauscher oscillating reaction is one of a small number of known oscillating chemical reactions.It is especially well suited for demonstration purposes because of its visually striking colour changes: the freshly prepared colourless solution slowly turns an amber colour, then suddenly changes to a very dark blue.
Here the red color compared to typical yellow color of the flames suggests that the temperature is lower. This is because there is a lack of oxygen in the room and therefore there is incomplete combustion and the flame temperature is low, often just 600 to 850 °C (1,112 to 1,562 °F).
The onset of thermal degradation dictates the maximum temperature at which a polymer can be used. It is an important limitation in how the polymer is manufactured and processed. For instance, polymers become less viscous at higher temperatures which makes injection moulding easier and faster, but thermal degradation places a ceiling temperature ...