Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Q: Sentence1: Heat and temperature are the same. 
Sentence2: a thermometer is used to measure heat.

A: Heat
****
Q: Sentence1: Light source is an ultra-bright, unbreakable LED Bulb. 
Sentence2: LEDs convert electricity into light and heat energy.

A: LED
****
Q: Sentence1: Earth 's tilt on its rotating axis causes seasons to change. 
Sentence2: Autumn brings the changing of the seasons.

A:
change
****