Science 8Bill Nye: BUOYANCYANSWERSMr. Birt

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  1. The weight of water makes things float.
  2. Whenever a boat is in the water, it displaces water.
  3. Displace means place away.
  4. Everything you put in water displaces water.
  5. The weight of the model boat on the scales was the same asthe weight of the two beakers of water it displaced from the tank.
  6. The two beakers of water displaced by the model boat, exactly filledthe cavity in the wax mold left by the model boat.
  7. The clay in a shape of a boat floats.
  8. The clay in the shape of a ball sinks.
  9. The shape makes the difference (whether it floats or sinks).
  10. The two shapes of clay (boat and ball) displaced the same amounts of water from the measuring cups.
  11. Boats made of stuff that sinks will float if they are shaped right.
  12. When objects are placed in water, they push water out of the way
  13. They displace some water.
  14. A personal floatation devise is also called a PFD.
  15. Things float because of buoyancy.
  16. Things that displace an amount of water that weighs as much as they do will float.
  17. We call this buoyancy.
  18. The tennis ball displaces as much water as it weighs and it ends up floating.
  19. The tennis ball cut in half floats a little higher because it doesn’t weigh as much.
  20. The tennis ball sinks until it displaces as much water as it weighs and then it floats.
  21. Archimedes realized that he could figure out how much volume things have if he knew how much water they displaced when they sink.
  22. The Titanic sank because eventually it was filled with so much water it was not displacing nearly as much water as it weighed.
  23. For the submarine in a bottle, as you squeeze the bottle you squeeze the air in the pen cap,
  24. The air in the pen cap takes up less room so it displaces less water and it sinks.
  25. A rock sinks so it has negative buoyancy.
  26. Wood floats so it has positive buoyancy
  27. The rock and wood together neither sink nor float so they have neutral buoyancy.
  28. Neutral means somewhere-in-between
  29. Using bubbles of air to control their depth is how submarines, fish and scuba divers keep at the same level in the water (neutral buoyancy).
  30. The weight of the floating car was being held up by the weight of the water.
  31. A buoyancy compensator is a vest filled with air used by scuba divers.
  32. As the vest fills with air, it displaces more water so you become more buoyant.
  33. When you are not sinking and not floating, you are neutrally buoyant.
  34. To repair ships they put them into a submerged dry dock then pump out all the water so it floats.
  35. Hot air balloons are like boats -- they have buoyancy because they are floating in air
  36. The hot air molecules in a hot air balloon are further apart than the cool air molecules outside the balloon.
  37. So the hot air inside the balloon weighs less than the cool air outside and the balloon floats.
  38. The hot air displaces the cool air around it and has buoyancy.
  39. A hot air balloon is like a bubble of air in water…it has buoyancy.
  40. A boat in water displaces an amount of water that weighs as much as it does so it floats.
  41. The car floats because it is shaped in a way that it displaces the same amount of water as it weighs.
  42. When an object displaces an amount of water that weighs as much as it does, it floats.
  43. If OBJECT WEIGHT = DISPLACED WATER WEIGHT  OBJECT FLOATS
  44. As long as an object weighs the same or less than the water it displaces then it floats.
  45. The car/boat and Bill Nye float because they displace an amount of water that weighsas much as they do.