Science Semester Study Guide
- The sun and the nine planets make up our solar system.
 - All the planets are held in orbit by a force called gravity.
 - Each of the nine planets moves in an orbit, or curved path, around the sun.
 - Mercury is the closest planet to the sun.
 - Venus is the second planet from the sun.
 - The earth is the third planet from the sun.
 - The earth is about 93 million miles from the sun.
 - The earth is 70% water.
 - The moon is the largest object in the night sky. It is 240,000 miles from earth.
 - The sun is 400 times larger than the moon.
 - Neil Armstrong was the first man to walk on the moon on July 20, 1969.
 - Thunderstorms are heavy rains with thunder and lighting.
 - Tornado is a large storm that forms over an ocean, the winds can go as fast as 500 per hour.
 - Hurricane is a violent but small storm that starts over land.
 - The Pacific Ocean is the largest ocean.
 - The Atlantic Ocean is the second largest ocean.
 - The Indian Ocean is the third largest ocean.
 - The Arctic is the smallest ocean.
 - Mount Everest is the highest mountain in the world.
 - An earthquake is shaking of the surface of earth when the plates of the earth move.
 - About one million earthquakes happen every year.
 - A tsunami is an earthquake underwater.
 - Natural resources that can replace, or renew, themselves in a short time are called renewable natural resources.
 - Natural resources that are replaced very slowly or not at all are called nonrenewable natural resources.
 - Conservation is the protection of Earth’s natural balance and the wise use of its resources.
 - Hibernation is sleeping through the winter.
 - Migration is traveling south to warmer areas to find food and returning north in the spring.
 - Protective coloring is called camouflage.
 - A fox hole is called a den.
 - The beaver builds a home in water. It is called a lodge.
 - All animals reproduce. They make more living things like themselves.
 - An animal that eats only other animals is a carnivore.
 - An animal that eat both plants and animals is an omnivore.
 - Invertebrates are animals that do not have a backbone.
 - Earthworms do not have eyes or ears.
 - Earthworms have 10 hearts.
 - The two most dangerous spiders are the black widow and the brown recluse.
 - Reptiles are vertebrates. A reptile is cold-blooded.
 - Alligators can be found in the southeastern United States.
 - Boa constrictor is the largest snakes in the world.
 - There are about 300 kinds of poisonous snakes in the world.
 - Birds are warm-blooded.
 - There are over 8,600 kinds of birds.
 - The largest bird is the ostrich.
 - The smallest bird is the hummingbird.
 - There are more than 4,000 different kinds of mammals.
 - Mammals are vertebrates.
 - Mammals are warm-blooded animals.
 - Apes belong to a group of mammals called primates.
 - Gibbons are the smallest apes.
 
