Chapter 3: Ocean Water

Transcription

1 Chapter 3: Ocean Water

2 CHAPTER 3 PROJECT - DENSITY BOTTLES During the Golf Ball Density lab, you will see the ways in which fresh water interacts with salt water when the two are mixed. The two forms of water have different densities and therefore, do not initially mix. This will happen any time you attempt to mix two liquids of different densities. Specifically, fresh water has a density of 1.00 g/cm3 and salt water has a density of 1.02 g/cm3. In addition to water, there are other liquids and substances that have different densities so if you attempt to mix them together, they simply will not. Here is a classic example mixing vegetable oil, water, and corn syrup together would result in 3 separate layers. In addition, you can add a popsicle stick, crayon, pasta, and a paper clip, which would all individually float on different layers. Your job is to take an empty soda/water bottle (12-20 oz.) and create your own density display (please remove the label or sticker). Pick any liquids/substances you want, as long as it s legal and appropriate, and create at least three (3) separate layers in your bottle. You will be graded on the following criteria: The ability to successfully demonstrate 3 separate layers Creativity (using oil, water, and corn syrup won t score many creativity points) Your fellow students will assist in the grading process. When all the bottles are submitted, we will placed them all on the back counter and the students will rank the top three most creative displays. Top-3 finishers will receive the following prize: 1st place 5 bonus points 2nd place 3 bonus points 3rd place 2 bonus points

3 CHAPTER 3 NOTES 1.Oceans cover % of the Earth. % of water on Earth is frozen. This leaves less than % for humans to drink. 2. Water exists in which 3 phases? 3. What is important about water and heating/cooling? 4. What is refraction? 5. What is the formula for density? 6. The density of pure water is and salt water is. 7. How does the density of ice compare to the density of fresh water? 8. What happens to salt as ocean water freezes? 9. The tip of the iceberg is actually what percentage? 10. What are the 3 steps of ice formation? a. b. c. 11. How much does water pressure increase with every 10m drop? 12. What do divers do to deal with increasing water pressure? 13. How does the speed of sound in water compare to the speed of sound in air? 14. How fast does sound travel in water? 15. What is the relationship between temperature and density? 16. How does light change as you go down in the ocean? 17. Which colors/wavelengths are absorbed in the first 10m of water? 18. Which wavelength can penetrate water the deepest? 19. Under what circumstances can light penetrate water the deepest?

4 20. What is the relationship between CO2 and ocean water? 21. Define salinity. 22. What does p.p.t. stand for? 23. What is the average salinity of the oceans? 24. Where does salt come from? 25. How can salt leave the oceans? 26. What circumstances provide high salinity in ocean water? 27. What circumstances provide low salinity in ocean water? 28. What is brackish water? 29. Pacific Ocean where the Columbia River empties out - high or low salinity? 30. Mediterranean Sea - high or low salinity? 31. Equator - high or low salinity? 32. What is the average salinity of the Dead Sea? 33. Why is the Dead Sea so salty? 34. What is the temperature of most ocean water? 35. What are the 3 layers of the ocean? 36. What mixes the mixed layer? 37. What is most special about the mixed layer? 38. How and why does the temperature of the mixed layer vary? 39. Define thermocline. 40. Where does cold water come from?

5 GOLF BALL DENSITY LAB Purpose: To understand the difference in density of salt water and fresh water. Materials: 1 clear plastic cup fresh water source 1 spoon 1 golf ball 1 dixie cup paper towels salt food coloring Pre-Lab Questions 1. Define salinity. 2. Define density. 3. Why might some golf balls float at a miniature golf course when you hit it in the water? Explain. Procedure: 1. Fill half of the cup with fresh water. 2. PLACE the golf ball into the cup (according to all dictionaries and contrary to most students beliefs, place does not mean the same as forcefully drop ). A. Does the golf ball sink or float? 3. Remove the golf ball from the cup and place it on the paper towel. 4. Using the spoon, take 1 teaspoon of salt and empty it into the cup. 5. Now that the salt has been added, stir the water so that all the salt dissolves and none can be seen at the bottom of the cup. 6. Place the golf ball in the water. B. Does the golf ball sink or float? 7. While keeping track of the amount of salt you put in the cup, repeat Steps #3-6 until the golf ball floats on top of the water. C. How many teaspoons of salt did it take to allow the golf ball to float?

6 8. If you have done everything correctly, the cup should still be about half full with the golf ball floating. Using Dixie cups, SLOWLY add fresh water to the salt water up to about an inch from the top of the cup. I cannot stress the word SLOWLY enough. D. What happens to the golf ball? Explain. 9. Add 3-4 drops of food coloring to the water. Do not stir, allow the food coloring to settle out. E.Does the food coloring mix throughout the entire cup of water? Why or why not? 10. Using the spoon, remove the golf ball. Return the following supplies to Mr. Mihalik at the front table: golf ball, cup of water (with water still in it), food coloring, spoon, and dixie cup. Please throw away the paper towels. POST-LAB QUESTIONS: 4. How would this lab have been different with a baseball and a ping pong ball? Explain both scenarios. 5. At a region where a freshwater source meets a salt water body, how do you think the water masses mix? 6. What did salinity have to do with this lab? 7. What did density have to do with this lab?

7 NAVAL ENGINEERING: TIN FOIL BOATS Objective: Your job is to make a boat out of a single sheet of tin foil that can hold the most pennies while floating on the water. Rules: 1. Using the aluminum foil and tape, construct a vessel that will float on water and hold a load of pennies. 2. You may not use anything else besides the tin foil given to you. 3. The boat that holds the most pennies wins, and the penny that causes the boat to sink does NOT count. Design Phase 1 In the space below, sketch what you want your boat to look like given a 12 x 12 piece of foil. Post-contest Questions: 1. Describe the final shape and design of your boat. 2. How did your boat differ from others? 3. Which was more effective and why? 4. If you had to do it again, what would you have done differently?

8 OCEAN WATER WEBSEARCH - PART I No websites will be given to you in advance. Use the internet and those search engines to find the answers to the questions below. COMPOSITION 1. Besides hydrogen and oxygen, what are the top 5 elements in seawater? 2. How did the ocean form? 3. Where did the salt in the ocean come from? 4. What gasses are dissolved in ocean water? TEMPERATURE 5. What areas of the globe have warm ocean water? What areas have cold ocean water? Why? 6. Does the East Coast or West Coast of the United States have warmer water? 7. What is the average temperature for the Jersey Shore water in July? What about January? 8. What happens to temperature as depth increases? SALINITY 9. What is the salinity range of the oceans from around the world? 10. What are some factors that change the salinity of water? 11. Why are there lower salinity values along the edges of continents? 12. Why is the salinity at the equator lower than the salinity in the subtropics? 13. What happens to the salinity as depth increases? DENSITY

9 14. What is the density of ocean water at the surface? 15. What happens to the density at the bottom of the ocean? COLOR 16. Why is the ocean blue? 17. What causes ocean water to look green? 18. What causes ocean water to look brown? OCEAN WATER WEBSEARCH - PART II Go to the following site: Traditionally, what do people think will happen if you drink too much salt water? 20. Dr. Bombard suggests you can drink how much salt water per day? 21. If you try and freeze salt water, where will the salt be concentrated and found? 22. What part of a large fish is a good source of water? Go to the following site: What is desalination? 24. Why is desalination not being used more often? 25. How does desalination occur in nature?

10 SEAWATER MIXING & SINKING 1. As temperature increases, density. 2. As salinity increases, density. 3. Which is denser - cold or warm water? 4. Where would ice belong on this T-S diagram? 5. Which has a greater density - Sample A or Sample B? 6. Mix Sample A and Sample B. What is the result? (Fill out the chart below) Temperature (C) Salinity (psu) Density (g/cm3) Sample A Sample B Sample C

11 TAKING THE OCEAN S TEMPERATURE INVESTIGATIONS 1. Examine the temperature profile for the low latitudes labeled A. The depth is in meters (m) and the temperature is in degrees Celsius ( C). The warmer water is found near the (surface) (bottom). 2. Most of the sunlight entering the ocean is absorbed very near the surface. This sun-warmed surface water mixes with cooler, deeper waters as winds, breaking waves and turbulent currents stir the water. One result of this mixing is a surface layer having nearly uniform temperature, or isothermal, conditions. This layer is called the mixed layer. On the low-latitude profile, the mixed layer extends a depth of (less than 500 m) (1,000 m) (4,000 m). 3. The temperature of seawater immediately below the mixed layer changes rapidly with depth. This layer of rapid temperature change extends down to about 1,000 m and is called the main thermocline. As the depth increase within this layer, the temperature (increases) (decreases). 4. The main thermocline separates the warmer mixed layer above from the cooler deep layer below. In the deep layer, the water is almost isothermal, with only a gradual decrease in temperature to the ocean floor. The top of this deep layer is found at a depth of (less than 1000m)(more than 1000m). 5. Examine the temperature profile for the mid-latitudes labeled B. This profile resembles the low- latitude profile but with some important differences. Compared to the low-latitude profile, the mixed layer temperature is (cooler) (warmer) and shows (seasonal variation) (no seasonal variation). 6. Now examine the temperature profile for the high latitudes labeled C. Compared to the low and mid- latitude profiles, the surface temperature is (cooler) (warmer) and a strong (isothermal) (thermocline) situation exists at these latitudes. 7. The accumulation of ocean temperature measurements from a variety of locations and depths has revealed that there is a three layered thermal structure in most of the ocean. In the warmer low and mid- latitudes, a main thermocline layer with rapidly changing vertical temperature separates the warmer surface mixed layer from the colder deep layer. Although this colder deep layer is found at all three latitudes, it extends essentially to the surface only at (low) (mid) (high) latitudes.

12 DUAL SURVIVAL - ADRIFT 1. This episode simulates what scenario? 2. What did they use to make a floatation device? 3. What type of resources do they have for survival? 4. What percentage of salt is in the ocean water? 5. What happens if a dehydrated person drinks seawater? 6. If you become seasick, what is the thing you should not do? 7. What ocean are they floating in? 8. How many islands are said to be uninhabited in the Pacific Ocean? 9. The dangers on a deserted island and being stranded in the ocean include: 10. What can a centipede s venom do to a person? 11. What does Cody do when he finds the coconuts? 12. What type of fire is Dave trying to make? 13. What does fire ward off at night?

13 14. What type of fish is one of the most venomous fish in the world? 15. What is Cody going to do with the fish oil can and copper tubing? 16. Why must there be an air tight sealant when placing the copper tubing inside of the fish oil can? 17. Why does the can need to be above the fire? 18. Why does Cody use tree sap? 19. What does Cody use to catch the fresh water? Naked And Afraid In the space below, make a list of all the ways they tried to get fresh water.

14 Surface Salinity and Evaporation The salt content (or salinity) of the surface waters of the ocean is determined by the amount of rainfall (precipitation) and the amount of fresh water that evaporates from the ocean. In regions where the amount of precipitation is higher than evaporation (negative net evaporation numbers), the ocean surface becomes diluted with fresh water and the overall salinity goes down. Conversely, if the evaporation rate is higher than the precipitation (positive net evaporation numbers), then fresh water is lost from the ocean surface, which increases the salinity. In this investigation you will consider the world wide patterns of sea surface salinity and net evaporation (evaporation minus precipitation). DIRECTIONS: On the following page, plot the salinity AND evaporation on the same graph. Then answer the questions below. 1. What is the approximate worldwide range in sea surface salinity, in ppt? 2. At what latitudes are salinity the highest? The lowest? 3. Pick a letter of the alphabet to describe the shape of the salinity graph. 4. What is the approximate worldwide range in net evaporation (evap - precip), in cm/year? 5. At what latitudes do you see negative evaporation (precipitation>evaporation)? 6. At what latitudes do you see positive evaporation (evaporation>precipitation)? 7. Pick a letter of the alphabet to describe the shape of the evaporation graph. 8. Describe any similarities you may observe between the shapes of the two graphs. 9. Overall, what is the relationship between latitude, the salinity of ocean surface water, and the net evaporation rate?

15 Latitude Salinity Evaporation Latitude Salinity Evaporation

16 CHAPTER 3 REVIEW SHEET 1. Define density. 2. What is the density of freshwater? 3. What is the density of salt water? 4. Define salinity. 5. How does the Dead Sea compare to the world s oceans in terms of salinity? 6. What is the salinity of the Atlantic Ocean? 7. Where would we find ocean water high in salinity? 8. Provide some examples of oceans/seas that are high in salinity. 9. Where would we find ocean water low in salinity? 10. Provide some examples of oceans/seas that are low in salinity. 11. Briefly explain the mixing of water where a river is flowing out into an ocean. 12. How do temperature and salinity affect mixing in the ocean (Seawater Sinking and Mixing Worksheet)? 13. How are temperature and density related? (Seawater Sinking and Mixing) 14. How are salinity and density related?(seawater Sinking and Mixing) 15. What are the 3 layers of the ocean? 16. Define thermocline.

17 17. Where does the salt in saltwater originate? 18. How does density affect an object or substance s ability to float? 19. How does latitude affect ocean temperatures? 20. Why is the ocean blue? 21. What are some reasons that water doesn t always appear to be blue? 22. What is desalination? 23. What is the problem with desalination? 24. How is salt water typically viewed when in a survival situation? 25. What are good sources of fresh water when you re in a survival situation on a typical beach? 26. How can you make fresh water out of salt water with household products?