Working as a zookeeper requires you to be passionate about animals and wildlife conservation. You often spend more time with the animals than other zoo employees, getting to know their habits and personalities. This helps you determine when the animals are healthy or whether they need veterinary care, a vital role of primary caregivers.
So on average the number of days between two similar phases (e.g. between one full moon and the next full moon) is about 29.531 days. This period is referred to as a lunation, lunar month, or synodic month.
Thus we have one full moon per month and 12 full moons per year. The full moon last only for one day because the moon travels on constantly. And we can predict the time point for full moon exactly by the second, because the moons orbit around the earth is known exactly. Bye.