Problem 88 - Chemistry: The Central Science

Question

A watch with a liquid crystal display (LCD) does not function properly when it is exposed to low temperatures during a trip to Antarctica. Explain why the LCD might not function well at low temperature.

Step-by-Step Solution

Answer

In conclusion, the LCD watch might not function well at low temperatures during a trip to Antarctica due to the phase transitions that liquid crystals undergo with the temperature change. This can affect their ability to align properly and respond to the applied electric field, which ultimately impacts the performance of the LCD display. The reduction in the mobility of the liquid crystals at low temperatures can also contribute to slower response times and poor display quality.

Step 1: Understanding Liquid Crystal Displays (LCDs)

LCDs work by using liquid crystals which have properties of both liquids and solids. These liquid crystals are arranged in layers, and their orientation can be controlled by applying an electric field. The electric field causes the liquid crystals to align, which modifies the way light passes through and interacts with them. With the aid of the polarizing filters, this results in being able to display information on the screen.

Step 2: Phase transitions in liquid crystals

When temperature changes, liquid crystals can go through different phase transitions. There are various phases for liquid crystals, including the nematic, smectic, and cholesteric phase, which have distinct properties in terms of their orientation and structure. For LCDs to function correctly, it is essential for the liquid crystals to be in the right phase. These phase transitions can be affected by temperature changes.

Step 3: Effect of low temperature on LCD

When an LCD display is exposed to low temperatures like in Antarctica, several things can happen to the liquid crystals. The most significant impact is that they might undergo a phase transition to a phase that is not suitable for LCD functioning. This can lead to the liquid crystals not responding well to the applied electric field, resulting in a poor display or complete loss of function. Additionally, the low temperature can reduce the overall mobility of the liquid crystals, making them less responsive to the applied electric field. This can lead to slow response times or sluggishness of the display.

Step 4: Conclusion

In conclusion, the LCD watch might not function well at low temperatures during a trip to Antarctica due to the phase transitions that liquid crystals undergo with the temperature change. This can affect their ability to align properly and respond to the applied electric field, which ultimately impacts the performance of the LCD display. The reduction in the mobility of the liquid crystals at low temperatures can also contribute to slower response times and poor display quality.