The Bible informs us that God created the moon on Day 4 of Creation Week (Genesis 1:14–19). Some of its functions are briefly described: it provides light and helps us plan out our calendars. But the moon has another important function: it helps create tides, the daily rise and fall of water along our shorelines. But how do tides work? This is a mystery that baffles people today, as it did people in the ancient past. Yet, it is not that hard to understand, if you think about it.