1. Future Fleet Science Topics: Buoyancy, Density and Volume

2. Future Fleet

3. SESSION ONE

4. History of Failed Ships

5. What is the economic cost of a failed ship design? Student Responses

6. History of Failed Ships What is the human cost of a failed ship design? Student Responses

7. History of Failed Ships How can the tragic losses in the article be prevented? Student Responses

8. History of Failed Ships Is it possible to know how much a ship will cost before you build it? Student Responses

9. History of Failed Ships Can an unsinkable ship be designed? Student Responses

10. History of Failed Ships Is it possible for a tragedy at sea to happen today, even with current technology? Student Responses

11. Lets Explore

12. Exploration Teams Assigning the teams Roles – Task manager – Activity recorder – Life Line – Evaluator

13. Task manager Keep group members focused

14. Activity recorder Records what the group does and what questions the members have

15. Life Line Can leave the group to seek help

16. Evaluator Judge the effectiveness of the group Report back only to the group

17. The Stations How Metal "Boats" Float (5 min) Liquid Density and Lava Lamp (5 min) Soda Can Pirouette (5 min) Students should move to their teams now and begin the exploration

18. TIME IS UP Please return to your seats

19. REPORT Each group should now report on the following: – Name one thing you learned that has not been mentioned yet Student Responses

20. Definitions and Calculations Density Displacement Mass Buoyancy Center of Gravity Center of Buoyancy Metacenter

21. Density D = M / V Solve the equation for mass M = D x V Mass can now be calculated -The degree of compactness of a substance -Mass per unit of Volume

22. The Density of Water Density is influenced by depth, temperature, and salinity. Look at the Salinity Map Salinity Map Look at the Temperature Map Temperature Map

23. Displacement Mass The mass of a fluid (as water) displaced by a floating body (as a ship) of equal mass 460 mega kilograms of water To stay afloat A 460 mega kilogram ship Needs to Displace

24. The Calculation of Displacement Mass 1) Find the density of water of operational area Density is influenced by depth, temperature, and salinity We will use about 34 PSU* Salinity as an operational area Salinity Map We will use about 30 degrees Celsius as an operational area Temperature Map At 20m depth the density will be 1.021 g/cm 3 *PSU * Salinity is measured by conductivity (how easily electricity flows through a seawater sample).

25. The Calculation of Displacement Mass 2) Find the volume of water being displaced Take the cross sectional area height x width 30 m x 5m 5 m 30m 3 m x 3m and multiply by the 3 rd dimension to find volume This gives us a Volume of 450 m 3

26. The Calculation of Displacement Mass 3) Find the displacement mass M = V x D Volume of Water (cm 3 ) x Density (g / cm 3 ) (450 m 3 x 1,000,000 cm 3 / m 3 ) x 1.021 g/cm 3 459450000 g

27. Weight vs. Mass So the volume can displace a mass of 459450000 grams or a weight of 459450000 g x (1kg/1000 g) * 9.8 m/s 2 = 4,502,610 N or 459450000 g x (1kg/1000 g) * 2.2lbs/kg= 1,010,790 lbs or 505.4 Tons - Weight is a force - Force in general is mass times acceleration

28. Buoyancy What is Buoyancy? Buoyancy is the upward force that a fluid exerts on an object less dense then itself. As mass is added, the boat displaces more water until the weight of the displaced water equals the weight of the boat; then the boat sinks.

29. Archimedes's principle. An object immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. Put picture of floating boy here

30. 5 m 30m 3 m A 500 Ton ship needs to displace a volume of 450m 3 to avoid sinking Summary of Buoyancy and Displacement

31. Displacement of irregular shapes Use graph paper to approximate the cross sectional area Then find the displacement mass

32. Center of Gravity What is the Center of Gravity? The center of gravity is the geometric property that represents the average location of the weight of an object. We can balance the scale by moving the fulcrum to the center of gravity.

33. How do we find the Center of Gravity? 1)Hang the object from a point 2)Hang a weighted string from the point and when it comes to a rest draw a line 3)Repeat with another point on the shape

34. Center of Buoyancy Is the center of gravity of the displaced water The center of buoyancy changes as the ship rolls and pitches The balance between center of buoyancy and center of gravity affects stability of the ship

35. Metacenter Ship Water

36. Center of Gravity Center of Buoyancy

37. Ship rolled at a small angle

38. New center of buoyancy Line of force for new center of buoyancy perpendicular to water line

39. The intersection of the two lines of force form the metacenter

40. The distance from the metacenter (M) to the center of gravity (G) is called the metacentric height (GM). G M

41. Metacenter A positive GM is needed to make a stable ship The higher the GM the more stable the ship The higher the GM the faster the ship will right itself. If this number becomes too high the ride will become rough.

42. Elaborate Work in your teams to come up with general guidelines for ship design.

43. Exit Ticket Find the displacement of mass of a ship segment with cross sectional dimensions of 30m by 8 m and a length of 10m. Student Responses

44. SESSION TWO Build a Prototype

45. The Littoral Class Future Ships of the Navy

46. The Littoral Class Why did the Navy use two different designs? Student Responses

47. The Littoral Class What need is the Navy trying to address? Student Responses

48. The Littoral Class What aspects of the design of the ships address the needs of the Navy? Student Responses

49. The Littoral Class Why do you think using all new 21 st century technology was important to these features? Student Responses

50. LCS and Pirates Click me to see Somalia Click me To see video

51. The Littoral Class How could the LCS class ships help support operations in the region? Student Responses

52. The design requirements Length must be 128 cm Width 32 cm Displacement depth 4.3 cm Hull shape up to the designers but ship must be stable and must displace its weight in water

53. Design Time Planning and calculationsBuild Time 25min35min

54. Evaluate The students will work in their design team on a brief description of their prototype. In this description the students should address the aspects of their prototype that are most closely related to a real ship (displacement and buoyancy). Students should then give themselves a confidence rating. This should represent how successful the ship will be in a full scale prototype. Focusing only on aspects related to a real ship, students should answer the question - “Is the design of their prototype worth spending several million dollars to test at full scale?” The students should answer the question - “Is the design of their prototype worth spending several million dollars to test at full scale?”

55. SESSION THREE Testing our Design

56. Presentations Each group will have 3 minutes to present their design to the class using the evaluation from Session 2

57. Evaluation of design Each team will put their prototype in the water tank and have it tested by the instructor. All students will record data on a rubric for each prototype. There are three categories: oPercentage error between predicted water line and actual water line (tank can have dye or food coloring in it to help denote the actual water line for measurement) oStability test under wave creation. Three levels of intensity for waves should be tested by dropping a weight in the water a short distance from the ship. oOverall design appeal and creativity – this is subjective

58. Improving on design Teams are to go back together and reevaluate their calculations to determine the following: Explanations for percentage error Stability of their prototype and what improvements could be made If they were to make another prototype what would they do differently?

59. The Littoral Class We looked at stability and buoyancy. What other variables might have to be addressed in building of a prototype? Student Responses

60. The Littoral Class How will designing versatile and flexible ships prepare us to handle the future? Student Responses

61. The Littoral Class Given the safety concerns about some modern cruise ships, how might one prevent future accidents like the Costa Concordia? Student Responses

62. Congratulations on finishing your designs of