Temperature change during electrophoresis is an important parameter to consider when optimizing already existing reagents or conditions or testing new reagents/conditions for agarose gel electrophoresis. 

To analyze the temperature change, two thermometers can be placed, one in anode chamber and other in cathode chamber. Digital thermometers can be used for this purpose. They allow easy monitoring of temperature change. Readings can be taken at several time intervals and an average reading at a particular time point can be considered as a result.

REFERENCES

Sanderson et al., 2014. Modification of gel architecture and TBE/TAE buffer composition to minimize heating during agarose gel electrophoresis. Anal Biochem. 454, 44-52. PMID-24637158; Full-Text Links: sciencedirect, PMC4021863