Study the first 3 graphics and then answer the questions that follow each. Once you are sure you understand how the lunar
day, the position of the sun and the moon, and orbital variations affect the tides, then try to apply this knowledge, and
Be the Captain.
Position of theSun and Moon
Be the Captain
Knowing when and how much the tides will rise and fall each day is important to beachcombers, mariners, fishermen, and the
people who operate seaside industrial and commercial facilities. Miscalculating the arrival and size of the tides can have
expensive, even deadly, consequences.
Predicting the tides is complicated because the tides are affected by many factors. In this activity, you'll have a chance
to consider some of the most important and universal influences, those due to the movements of the sun, the moon, and the
earth. In reality, a number of local and transient factors, such as the shape of the coastline, the flow of currents, and
the weather, must also be taken into account.
Play the animation and observe the relationship between the lunar day and the time, then answer the
Over the course of what is called a lunar day, a spot on earth that is directly beneath the moon rotates once until
the moon is again exactly overhead. Because the earth spins in the same direction that the moon orbits the planet,
the cycle is slightly longer than a regular day -- it takes 24 hours and 50 minutes.