fresh water
ocean
earth, moon, sun
Atmosphere
Solar System
100

tiny algae and animals floating on ocean's surface

plankton

100

wise use of a resource so it won't be used up

conservation

100

device that goes between earth and space

shuttle

100

most abundant gas in atmosphere

nitrogen

100

force propelling object forward

thrust

200

process of supplying water to land to make suitable for crops

irrigation

200

process in which molecules at the surface of liquid absorb enough energy to change to gaseous state

evaporation

200

spacecraft best suited to explore different planets than Earth

probe

200

particles of carbon that enter the air when wood is burned

soot

200

speed in a given direction 

velocity

300

cold and warm ocean water carried around the world

currents

300

process in which water is given off through leaves

transpiration

300

as the density of aior decreases, its pressure....

decreases

300

one cause of acid rain is when coal burns it contains a lot of this substance

sulfur

300

device that expels gas in one direction to move in opposite direction

rocket

400

This causes ocean currents to curve to the right in Northern Hemisphere

Coriolis effect

400

ampount of substance in volume of another substance

concentration

400

gas in the atmosphere that varies in different places from time to time

water vapor

400

force per unit area

pressure

400

velocity a rocket must reac to reach beyond a planet's gravitational pull

escape velocity

500

coastal area where fresh and salt water mixes

estuary

500

farming of saltwater and freshwater organisms

aquaculture

500

air pressure is often measured in this

millibars

500

4 main layers of atmosphere are classified according to this

temperatuire

500

velocity a rocket must achieve to orbit

orbital velocity