A simple glass bulb thermometer is an example of a first-order system where the input is the surrounding temperature (Tin) and the output is the temperature of the liquid inside the bulb (Tout), which expands to provide a reading on a scale. Using basic heat transfer principles, where the rate of convective heat transfer to the liquid equals the rate of change of internal energy of the fluid, derive the system equation and put it in standard form. Identify the time constant and relate the heat transfer parameters and fluid properties to the electrical parameters in an RC circuit (see Question 4.19). The parameters in your equation should include the fluid mass (m) and specific heat (c), and the bulb external area (A) and heat transfer coefficient (h).