Rikei ga Koi ni Ochita no de Shoumei shitemita. Heart EP6 - Science-types Fell in Love, So They Tried Not Trying to Prove it.

Yukimura is working hard on his computer, as usual, when Himuro suddenly says, "I am in love with you. Her confession greatly shakes Yukimura. Unlike the last time, Himuro states her feelings matter-of-factly. Yukimura asks, "What theory did you use to determine that you love me?" Himuro replies by taking Yukimura out on a date and begins performing experiments they've done before such as measuring heart rates, using an emotion counter, collecting saliva, and the kiss experiment.