These two pictures were taken on the same day, at the same spot on Washington State's Strait of Juan de Fuca. What a difference a few hours make! The first photo, on the left, was taken at high tide.	The photo above was taken six hours later at low tide. Notice: an entire small rocky peninsula has been exposed to our view. Moreover, the plants and animals that live there are now exposed to air.
The tide rises and falls twice every 24 hours and 50 minutes because the gravitational forces of the sun and moon are constantly pulling on the oceans. The moon, being close to us, pulls the hardest. Wherever the moon is positioned, the ocean below it forms a slight bulge. On the other side of the Earth, an opposing bulge appears. This is because the moon's pull on the ocean there is less than its tug on the Earth. Think of two giant ocean waves on opposite sides of the Earth, rotating slowly around it, trailing just behind the orbiting moon. These two high tides pass over our region daily, spaced apart by about 12 1/2 hours. Low tides occur in between.
The photos above and right were also taken along the northwest coast at low tide. Try to picture what these same shores will look like when the tide returns. Above: At high tide what will the large rock formation be shaped like? Right: At high tide where will these beachcombers be walking?
	Dad explains that we're here on the coast during a Spring Tide. These very low tides, ones that expose so many marine animals and plants, happen when the Earth, Sun and Moon are in a straight line. "Spring" doesn't have anything to do with seasons; it means that the water is extremely active, "springing up and down." So spring tides are the highest and lowest tides of the month.
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