Tides (pgs 63-65, 150-151 & 161-163)

Question 1

What causes the tides?

Answer 1

The interaction between the sun and the moon’s gravity causes the tides.

Question 2

What are spring and neap tides?

Answer 2

Spring tides occur when the sun and moon’s gravity pulls in the same direction, making high tides higher and low tides lower during the new and full moons. Neap tides occur when the sun and moon’s gravity pulls in opposite directions, make tides less extreme during half moons.

Question 3

What is MHWS?

Answer 3

Mean High Water Springs. It is the average level of the highest high tides.

Question 4

What is MLWS?

Answer 4

Mean Low Water Springs. It is the average level of the lowest low tides.

Question 5

What is MHWN?

Answer 5

Mean High Water Neaps. It is the average level of high tides during a neap tide.

Question 6

What is MLWN?

Answer 6

Mean Low Water Neaps. It is the average level of low tides during a neap tide.

Question 7

What is chart datum?

Answer 7

A level so low that the tide will very rarely fall below it. It is used as a reference from which to measure depths.