The fascinating experience of ebb and flow is inseparably connected to the North Sea. The water level at the coast rises two times a day by 2 – 3,5 meters. This silent behavior of the water is called flow. Likewise, the level decreases twice per day – and the ocean retreats. This is called ebb. Ebb and flow together last for about 12 hours and 24 minutes, meaning that the tides are changing by 48 minutes per day, approximately. Responsible for this sight are two forces: The centripetal force and the gravity between earth and moon. Their summarized vector is greatest during new- and full-moon resulting in the highest and lowest water levels. Is this a little bit complicated? This might be, but you don’t have to understand the exact physics behind it to appreciate this phenomenon; when the sea retreats the mudflat with its many residents appears, and that is something worth watching for sure.