What is the primary function of a helix strip bimetallic thermometer?

The primary function of a helix strip bimetallic thermometer is to amplify the motion of the pointer. This type of thermometer utilizes the properties of two different metals that expand at different rates when heated. The bimetallic strip is formed by bonding these two metals together. As the temperature changes, the varying rates of expansion cause the strip to bend. This bending motion is then translated into the movement of a pointer on the thermometer scale.

By using the helix design, the thermometers can enhance the movement of the pointer, allowing for a more readable temperature measurement. This is particularly important in practical applications where precise observation is required, as the mechanical advantage gained from the helix design enables even small temperature changes to be reflected clearly on the scale. Thus, the amplification of the pointer's motion is central to the thermometer's ability to indicate temperatures effectively. The other answer choices do not pertain to the primary function of this type of thermometer, as it is not intended for measuring pressure changes, indicating humidity, or solely focused on precision in a way that does not involve the amplification of motion.