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# Science Exam Reveiw

Term | Definition |
---|---|

Fluid | Any material that can flow and takes the shape of its container |

All fluids exert _______ | Pressure |

Fluids can also be _____ | Gases |

Pressure | The amount of force exerted on a given area |

Pressure = (math) | Force / area |

SI Unit for pressure | pascal (Pa) |

Atmospheric | The layer of nitrogen, oxygen and other gases that surround the earth |

Atmospheric Pressure | The pressure caused by the weight of the atmosphere |

There are __N (_lbs) of pressure on every ______ _________ of your body | 10N (2lbs); square centimeter |

Which direction do the fluids in your body exert pressure in? | The fluids exert pressure outward |

How far does the Earth's atmosphere stretch? | About 150km above the Earth |

__% of the Earth's gases are found within the first __km of the atmosphere | 80%; 10km |

At the top of the atmosphere pressure is almost ___________, pressure is close to _Pa | nonexistent; 0Pa |

Water pressure _________ as depth _________ | Increases; increases |

Pressure depends on the _____ not on the total amount of fluid | Depth |

Water is 1000 times more _____ than air | Dense |

Density | The amount of matter in a given volume |

Fluids flow from areas of ____ pressure to areas of ___ preessure | High pressure; low pressure |

Buoyant Force | The upward force that fluids exert on all matter |

Pressure _________ as depth _________ | Increases; increases |

Water exerts a ___ ______ force (buoyant force) | Net upward |

Archimedes was... | Greek mathematician in the 3rd century |

Archimedes Principle | States that buoyant force on an object in a fluid is an upward force equal to the weight of the fluid that the object takes the place of or displaces |

An object will ____ if its weight is greater than the buoyant force | Sink |

An object will _____ if the buoyant force on the object is equal or more than equal to the objects weight | Float |

Floating and Sinking Density = (math) | 1m = 1cm cubed - 5L of water = 5000cm cubed |

Density = (math) | Mass / volume |

FInd the density of a rock that has a mass of 10g and a volume of 2cm cubed | 5gcm cubed |

How does a ship made of steel float if steel is denser than water? | - Ships are built with a hollow shape - Same amount of steel bu the hollow shape increases the volume of the ship - Overall density is less than the density of the water |

Why are ships built to displace more water than needed? | Bc there are people and luggage on the boat (extra weight other than the ship) |

What are ballast tanks and what do they do? | - Tanks in a submarine that allow it to float/sink - When they open water flows in, making it its mass increase (volume stays the same) - When closed, they pump air in, making it less dense (allowing it to float) |

What is a swim bladder and what does it do? | - Swim bladder on a fish - It fills with gases (increasing volume, decreasing overall density) - It keeps the fish from sinking |

Daniel Bernoulli | Swiss mathematician in the 18th century |

Bernoulli Principle | States that as the speed of a moving liquid increases, the fluid pressure decreases |

How do planes fly? | Fast moving air above the wing exerts less pressure than slow moving air below the wing |

The speed of a plane is mostly determined by its: | Thrust and Larger thrust |

Thrust | Forward force that produces by the planes engine |

Larger Thrust | Increases speed, air travels around the wing at a higher speed which increases lift |

Drag | A force that opposes or restricts motion in a fluid |

Turbulence | An irregular or unpredictable flow of fluids |

How do you determine the speed of air crafts? | Calculate the drag in combination with thrust |

____ is often reduced when turbulence causes drag | Lift |

Planes use their flaps to change the shape of the area of the wing to reduce ____ and increase ____ | Reduce drag; increases lift |

Blaise Pascal | French scientist in the 17th century |

Pascal Principle | States that a change in pressure in an enclosed fluid will be transmitted equally to all parts of that fluid |

Work | A force that causes an object to move in the direction of the force |

For work to be done on an object, the object must move in the ____ direction as the force | Same direction |

Work = (math) | Force x Distance |

Power | The rate at which energy is transferred |

Power = (math) | Work / Time = Joules |

Power measures what? | How fast work happens or how quickly energy is transferred |

Increase work, _________ power | Increase |

Decrease work, ________ power | Decrease |

Machine | A device that makes work easier by changing the size ro direction of a force |

Work is done when a force is applied through a ________ | Distance |

Work input | The work you do on a machine |

Work output | Work done by the machine on an object |

Created by:
madisonradd