Transcript (Lesson 16) Gravity and Tides.pptx

Up and Down, In and Out
Gravity and Tides
Lesson 16
Making sense of the tide table:
• Find the highest tide within the two weeks.
• Find the lowest tide within the two weeks.
• What do the high tide and low tide numbers
mean?
• Find the day with the Full Moon Phase.
• Find the day with the New Moon Phase.
• How many high tides per day?
• How many low tides per day?
Why are tides important?
• You live in the
Northwest. Do you like
to explore the following
bodies of water?
– Puget Sound
– Pacific Ocean
• If so you need to know
about tides.
• What about Lake
Washington????
• Beach scenario:
• On Memorial Day
(5/30) you and your
family are planning a
trip to Alki Beach
(across from Seattle) to
have a sandcastle
building contest.
• What time of day will
you want to have your
competition?
Sea
Stacks
2How many tides per day? (Pg. 256)
Top
View
• Two high
tides per day
(positions
A and C)
• Two low
tides per day
(positions
D and E)
Spring and Neap Tides (Pg. 257)
• Two spring
tides per
month (New
and Full
Moon)
• Two neap
tides per
month (1st
and 3rd
Quarter)
Let’s take a look at the data:
Ebb, Flood and Slack
o Ebb Tide/Current: When the
water is going out (the
water level is going down).
o Flood Tide/Current: When
the water is coming in (the
water level is rising).
o Slack Tide/Water: When the
water stops for just an
instant and turns around
(occurs at high tide and low
tide).
Not to Scale

Tidal Bulge
Moon’s Pull
on Earth
Sun’s Pull
on Water
Earth
Sun
Moon’s Pull
on Water
Moon