INVESTIGATING TIDAL RANGES

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1 Name Period ÿ Date INVESTIGATING TIDAL RANGES TIDES are the daily rising and falling of Earth's ocean levels caused by the GRAVITATIONAL forces of the Moon and the Sun acting on the oceans. The gravity of the moon pulls on every particle of the Earth, but the pull is much more noticeable in liquids than in solids because liquids move more easily. Even the liquid in a glass of iced tea is slightly pulled by the moon's gravity. Got "FulJ Moon Madness"? It might just be the moon's gravitypulling on your body, which is anywhere The highest point on the beach the sea rises to each day is known as HIGH hide, while the lowest point the sea falls to is known as Low hide. But tide levels vary throughout the month as well as throughout the day. When the sun is in line with the Earth and moon, a condition known as syzygy, the gravitational forces ore especially strong, and a SPRING TIDE occurs. This has nothing to do with the season, but rather from the meaning of the word, which is "to leap up". During these times of the month, high tide is very high and low tide is very low. This means that the range, or difference gÿna-t---.:: pull between sun - moon and earth pull between ÿ[ÿ.',!:ÿ earth Neap Tide ] between the high and low tide levels will Spring Tide be greatest for these times of the month. The ocean is really moving! Spring tide brings the extremes twice every month and occurs during the new and full moon phases. When the Earth is positioned at a right angle.to the sun and the moon, a NEAP hide occurs. During this time, the high tide is not very high "and the low tide is not very low. There's just not much of a difference between the two and the range between high and low is not great at all...just a little "ocean motion". Neap tides occur twice every month and occur during the moon's first quarter and last quarter phases. 4ÿ PROBLEM: How does the tidal range for South Padre Island vary during March? PROCEDURE: 1. Use the data in the data table to calculate the tidal range for South Padre Island for every day during the month of March. Do this by subtracting the low tide height from the high tide height. Record the results of your calculations in the data table. 2. Plot the tidal range versus the date on the graph. Connect the points with straight-line segments. 3. On your graph, label the parts of the graph that correspond to the spring tides and neap tides.

2 TABLE 1. March tidal range for South Padre Island. iÿ: :!ÿ! Y!! i Y : h U!! H!gH i i! iÿ iÿÿ,! Low 1ÿ% i O , , ,0 0, ,7,1.7!,7 1.6 i , ,3-0.2 TibAL RANGE (METierS) L a l,l 1,5 1.0!, loq HELPFUL HINTS:, 0.0 is the average height of sea level for South Padre. Therefore, the high positive numbers are the really high tides and the low negative numbers are the really low tides. - But its not the overall high and low you're looking for...it's the range, or difference between the highs and lows that you are concerned about here. We're looking for the biggest overall change. e Remember your math when subtracting...two negatives make a positive. Example: - (-0,1) =

3 Name Period Date INVESTIGATING TIDAL RANGES Graph the tidal range data from Table 1. labels, and add an appropriate title. Don't forget to finish the data ranges for each axis, add axis 2.1 i t... 1,4 ÿ.ÿ i I O Date in March

4 DATA ANALYSIS QUESTIONS. Answer the following in complete sentences. Which day(s) had the smallest tidal range where there was not much difference between high and low tide (Neap Tide)? 2. Which day(s) had the greatest tidal range where there was a large difference between high and low tide (Spring Tide)? 3. On average, how many days apart are the three highest points on the graph? 4. On average, how many days apart are the two lowest points on the graph? 5. On what days do you think the moon was in either its full or new phase? EXPLAIN! 6. On what days do you think the moon was in either its first quarter or last quarter phase? EXPLAIN! 7. The entire lunar cycle takes about 28 days to complete. A. Approximately how many days apart are the full moon and new moon? B. Approximately how many days apart are the first quarter moon and last quarter moon? Use the diagram to the right to answer the following questions. 8. Which two phase numbers would most likely occur during Spring Tide? THE LUNAR ÿydle l_ 9. Which two phase numbers would most likely occur during Neap Tide? 6

5 Surf's Up, Dude Congratulations! You have just landed a new job for the Extreme Surfing Tour! Your boss has handed you a single month for you to plan a single event, First you will pick a location from the map based on your month, (Hint: What type of weather would bring out more fans?) After picking the location, draw and label the rest of the moon phases as indicated on the calendar. You will then pick the date within the month. (Hint: Which tides would give you the best extreme surfing?) " 1 2 Moon Phase: Vloon Phase: Aoon Phase: Moon Phase: ;29 30 Moon Phase: Event date: Why did you pick this date?

6 SWEET SURF SPOTS! " '..ÿ.,2... ' % '" ". ÿ, 'WUn tifd Kingdom ÿiÿ' 'ÿ%..,;':ÿ.ÿ ÿ"..j... i'!i" ":?;"',"i ÿ' Japan Cahformaÿ,, ÿ ',,ÿ - ',;,,.... % I ÿ,l / ÿ "... ÿ %' - \ ÿ ", *. '...,ÿ!iÿ! ÿ ÿ,"ÿ 1, { /.., "(,7 i. V' ÿ) f '.% : ÿ', ÿ, ÿ.ÿ, Equator (, '\ ", %!' t.,?ar'ge ntina J South Africa "Australiaÿ: "" V,ÿ:W,~f,.. 7.: Which of the above locations will you choose to hold the surfing event? Why did you pick this location?