A student uses a water bath to investigate how the electrical resistance of a thermistor changes over a temperature range from 15∘C15^{\circ}\text{C}15∘C to 90∘C90^{\circ}\text{C}90∘C.
State one modification the student could make to the experimental setup to investigate temperatures above 100∘C100^{\circ}\text{C}100∘C.