Science

• White blood cells, the skin


  Protect the body against certain harmful organisms
• Antibodies are similar to white blood cells and the skin in that they protect the body against certain harmful organisms
• Magnet


  Metallic substance capable of attracting iron and certain other metals
• 1. pole of a bar magnet is brought near the N-pole of another bar magnet


  The magnets will attract each other
• Magnetic lines of force


  Can be demonstrated with a magnet and iron filings
• Dry cell


  Has a low voltage, metallic case is made of zinc
• Christmas tree lights


  If the removal of one lamp will cause the rest to go out, they are connected in series circuits
• All planets move in elliptical orbit in the same direction around the Sun, and they lie in almost the same plane except Pluto
• The Earth travels around the Sun once each year, and spins on its axis once each day
• Mixture


  A combination of elements or compounds that can be separated by physical means
• Air can be liquefied, water molecule is composed of two atoms of hydrogen and one atom of oxygen, compounds contain two or more substances that can be separated by physical means
• Mammals


  Give birth to their young, feed their young on milk with mammary glands
• Lizard


  Cold blooded with a dry scaly skin
• Photosynthesis


  The food-making process in green plants, affected by the concentration of carbon dioxide, uses up oxygen, produces glucose and oxygen
• Machine


  Helps humans work more efficiently by increasing or multiplying force, increasing speed, or changing the direction of a force
• A machine that does not multiply force, increase speed, or change the direction of force decreases work
• Diagram shows a man using a

  • Lever
• Jackscrew


  Combination of an inclined plane and a screw
• Friction


  Slows down the movement of one object over another
• Gears


  Used in a bicycle to increase the speed at which the wheels turn
• Fuel


  Provides the energy to power some machines
• Oil


  Put on the bearings of wheels to reduce friction
• Object immersed in water


  Displaces a volume of water equal to its own volume
• Sinking object


  Displaces a volume of liquid equal to its own
• Floating object


  Displaces a volume of liquid less than its own
• Glowing splint


  Bursts into flame when exposed to oxygen gas
• Bubbling soft drinks or sodas


  Due to the carbon dioxide dissolved in the liquid
• Burning coal


  Releases stored chemical energy in the form of thermal energy
• Hydrogen


  Much lighter than air
• Energy


  Can be transformed from one form into another, but cannot be created or destroyed
• Photosynthesis in plants


  Stores the energy from the sun
• Salt in the ocean

  Comes from mineral dissolved in the earth and constant evaporation from ocean water
• Water


  Composed of hydrogen and oxygen
• Steel suspension bridge


  Sags in summer due to the steel expanding from the heat
• Spaces between cement blocks in a sidewalk

  Allow for drainage and prevent cracks due to expansion
• Bent metal pipe


  Cannot be seen through because light travels in a straight line
• Seeing printed paper


  Light is reflected from the paper to your eyes
• Convex lens in a reading glass

  Magnifies nearby objects
• Density of an object


  Equal to the ratio of its mass to its volume, an object less dense than water will float
• Oil or grease on steel


  Prevents rusting by keeping air away from the metal