| A | B |
| landform | the natural shape of the Earth's surface |
| mountain | a place on Earth's surface that is much higher than the land around it |
| valley | a low area between higher landforms |
| canyon | a valley with steep sides that have been carved by forces of nature |
| plain | a wide, flat area on Earth's surface |
| plateau | a flat area higher than the land around it |
| weathering | Big rocks are broken into smaller pieces |
| erosion | the movement ofweathered rock |
| glacier | a huge block of moving ice |
| earthquake | the shaking of Earth's surface |
| volcano | an oopening on Earth's surface from which lava flows |
| flood | a large amount of water that covers normally dry land |
| fresh water | water that has very little salt in it |
| groundwater | the underground supply of water |
| condensation | gas turning into a liquid |
| evaporation | liquid water gains thermal energy and turns into water vapor |
| precipitation | rain, snow, sleet, or hail fall to Earth |
| water cycle | powered by the Sun-water evaporates into water vapor, rises and condenses into clouds and falls as precipitation |
| atmosphere | air around Earth |
| oxygen | a gas that people need to live |
| weather | what is happening in the atmospher at a certain place and time |
| temperature | the measure of how hot or cold something is |
| anenometer | a weather instrument that measures wind speed |
| axis | imaginary line through Earth |
| rotation | spinning of Earth on its axis |
| moon phases | the different shapes we see that is lit by the Sun on the moon |
| lunar cycle | the pattern of moon phases |
| lunar eclipse | when Earth blocks sunlight from reaching the moon |
| solar eclipse | when the Moon's shadow falls on Earth |
| energy | ability to make something move or change |
| kinetic energy | the energy of motion |
| potential energy | the energy of position |
| combustion | another word for "burning" |
| revolution | movement of Earth around the Sun |