Grade 6 Science Chapter 10

Front 1

spectroscope

Back 1

an instrument that splits white light into a band of colors

Front 2

light-year

Back 2

the distance that light travels n one year, about 9.46 trillion kilometers

Front 3

nebula

Back 3

a large cloud of dust and gas in interstellar space; a region in space where stars are born

Front 4

open cluster

Back 4

a group of stars that are close together relative to surrounding stars

Front 5

globular cluster

Back 5

a tight group of stars that look like ball and contain up to 1 million stars

Front 6

comet

Back 6

a small body of ice, rock and cosmic dust that follows an elliptical orbit around the sun and that gives off gas and dust in the form of a tail as it passes close to the sun.

Front 7

asteroid

Back 7

a small, rocky object that orbits the sun; most asteroids are located in a band between the orbits of Mars and Jupiter

Front 8

mete0roid

Back 8

a relatively small, rocky body that travels through space

Front 9

meteor

Back 9

a bright streak of light that results when a meteoroid burns up in Earth's atmosphere

Front 10

meteorite

Back 10

a meteoroid that reaches Earth's surface without burning up completely

Front 11

rotation

Back 11

the spin of a body on its axis

Front 12

orbit

Back 12

the path that a body follows as it travels around another body in space

Front 13

revolution

Back 13

the motion of a body that travels around another body in space; one complete trip along an orbit

Front 14

day

Back 14

the time required for earth to rotate once on its axis

Front 15

equinox

Back 15

the moment when the sun appears to cross the celestial equator

Front 16

solstice

Back 16

the point at which the sun is as far noirth or as far south of the equator as possible

Front 17

phase

Back 17

the change in the sunlit area of one celestial body as seen from another celestial body

Front 18

eclipse

Back 18

an event in which the shadow of one celestial body falls on another

Front 19

tide

Back 19

the periodic rise and fall of the water level in the oceans and other large bodies of water

Front 20

tidal range

Back 20

the difference in levels of ocean water at high tide and low tide

Front 21

spring tide

Back 21

a tide of increased range that occurs two times a month at the new and full moons

Front 22

neap tide

Back 22

a tide of minimum range that occurs during the first and third quarters of the moon

Front 23

cell

Back 23

the smallest unit that can perform all life processes; cells are covered by a membrane and have DNA and cytoplasm

Front 24

stimulus

Back 24

anything that causes a reaction or change in an organism or any part of an organism

Front 25

homeostasis

Back 25

the maintenance of a constant internal state in a changing environment

Front 26

sexual reproduction

Back 26

reproduction in which the sex cells from two parents unite to produce offspring that share traits from both parents

Front 27

asexual reproduction

Back 27

reproduction that does not involve the union of sex cells and in which one parent produces offspring that are genetically identical to the parent

Front 28

heredity

Back 28

the passing of genetic traits from parent to offspring

Front 29

metabolism

Back 29

the sum of all chemical processes that occur in an organism

Front 30

producer

Back 30

an organism that can make its own food by using energy from its surroundings

Front 31

consumer

Back 31

an organism that eats other organisms or organic matter

Front 32

decomposer

Back 32

an organism that gets energy by breaking down the remains of dead organisms of animal wastes and consuming or absorbing the nutrients

Front 33

protein

Back 33

a molecule that is made up of amino acids and that is needed to build and repair structures and to regulate processes in the body

Front 34

carbohydrate

Back 34

a class of energy-giving nutrients that includes sugars, starches and fiber; contains carbon, hydrogen and oxygen

Front 35

lipid

Back 35

a type of biochemical that does not dissolve in water; fats and steroids are lipids

Front 36

phospholipid

Back 36

a lipid that contains phosphorus and that is a structural component in cell membranes

Front 37

ATP

Back 37

adenosine triphosphate, a molecule that acts as the main energy source for cell processes

Front 38

nucleic acid

Back 38

a molecule made up of subunits called nucleotides

Front 39

cell

Back 39

the smallest unit that can perform all life processes; cell are covered by a membrane and contain DNA and cytoplasm

Front 40

organism

Back 40

a living thing; anything that can carry out life processes independently

Front 41

prokaryote

Back 41

a singe-celled organism that does not have a nucleus or membrane-bound organelles; examples are archaea and bacteria

Front 42

eukaryote

Back 42

an organism made up of cells that have an nucleus enclosed by a membrane; eukaryotes include protest, animals, plants and fungi but not archaea or bacteria

Front 43

function

Back 43

the special, normal, or proper activity of an organ or part

Front 44

structure

Back 44

the arrangement of parts in an organism

Front 45

tissue

Back 45

a group of similar cells that perform a common function

Front 46

organ

Back 46

a collection of tissues that carry out a specialized function of the body

Front 47

organ system

Back 47

a group of organs that work together to perform body functions