Science Terms A-C

Question 1

acceleration

Answer 1

the rate that velocity changes per unit of time and the direction it changes in, computed from the change in velocity divided by the change in time. Common units are meters per second squared (m/s2).

Question 2

** acceleration due
to gravity**

Answer 2

the acceleration of an object that is only acted on by the force of the Earth’s gravity. This value is given the symbol g, and near the surface of the Earth it has a value of approximately 9.8 m/s2. The direction of acceleration due to gravity is downward.

Question 3

accuracy

Answer 3

the closeness of an experimental measurement to the accepted or theoretical value

Question 4

acid

Answer 4

a substance that is a proton donor. The pH of an acid is less than 7.

Question 5

analysis

Answer 5

a stage in the scientific method where patterns of the observations are made

Question 6

aqueous solution

Answer 6

a solution in which the solvent is water

Question 7

arteries

Answer 7

the vascular tissues that carry blood away from the heart

Question 8

astronomy

Answer 8

the study of the planets, stars, and space

Question 9

atom

Answer 9

the smallest structure that has the properties of an element. Atoms contain positively charged protons and uncharged neutrons in the nucleus. Negatively charged electrons orbit around the nucleus.

Question 10

ATP

Answer 10

(Adenosine Triphosphate) a chemical that is considered to be the “fuel” or energy source for an organism

Question 11

atria

Answer 11

the chambers of the heart that receive blood

Question 12

** base **

Answer 12

a substance that is a proton acceptor. The pH of a base is greater than 7.

Question 13

calibration

Answer 13

the examination of the performance of an instrument in an experiment whose outcomes are known, for the purpose of accounting for the inaccuracies inherent in the instrument in future experiments whose outcomes are not known

Question 14

capillaries

Answer 14

vascular tissues that receive blood from the arterioles and releases the blood to the venuoles

Question 15

catalyst

Answer 15

an agent that changes the rate of a reaction, without itself being altered by the reaction

Question 16

celestial equator

Answer 16

the extension of the Earth’s equator out onto the celestial sphere

Question 17

** celestial poles**

Answer 17

the extension of the Earth’s north and south poles onto the celestial sphere

Question 18

celestial sphere

Answer 18

the imaginary sphere which all the stars are viewed as being on for the purposes of locating them

Question 19

cell membrane

Answer 19

an organelle found in all cells that acts as the passageway through which materials can pass in and out. This organelle is highly selectively permeable, only allowing materials to pass through that it “chooses” chemically.

Question 20

cell wall

Answer 20

an organelle found primarily in plant cells and fungi cells, and also some bacteria. The cell wall is a strong structure that provides protection, support, and allows materials to pass in and out without being selectively permeable.

Question 21

centripetal force

Answer 21

the net force that acts to result in the centripetal acceleration. It is not an individual force, but the sum of the forces in the radial direction. It is directed toward the center of the circular motion.

Question 22

chemical change

Answer 22

a process that involves the formation or breaking of chemical bonds

Question 23

** chromosome**

Answer 23

an organelle that contains the entire DNA of the organism

Question 24

component

Answer 24

the part of a vector that lies in the horizontal or vertical direction

Question 25

compound

Answer 25

a substance composed of more than one element that has a definite composition and distinct physical and chemical properties

Question 26

concentration

Answer 26

a measure of the amount of solute that is present in a solution. A solution that contains very little solute is called dilute. A solution that contains a relatively large amount of solute is said to be concentrated.

Question 27

conclusion

Answer 27

the last stage of the scientific method, where explanations are made about why the patterns identified in the analysis section occurred

Question 28

constellation

Answer 28

an apparent grouping of stars in the sky that is used for identification purposes. These stars are not necessarily near each other in space, since they are not necessarily the same distance from the Earth.

Question 29

**continental rift **

Answer 29

the region on a continent where new crust is being created, and the plates on either side of the rift are moving apart

Question 30

**convergent boundary **

Answer 30

a boundary between two of the Earth’s plates that are moving toward each other

Question 31

**cosmology **

Answer 31

the study of the formation of the universe

Question 32

**crystal **

Answer 32

a solid in which atoms or molecules have a regular repeated arrangement

Question 33

**current **

Answer 33

the flow of charge past a point per unit time; current is measured in amperes (A)

Question 34

**cuticle **

Answer 34

the top layer on a leaf. It is a non-living layer consisting primarily of wax that is produced by the epithelium, a cell layer directly underneath.

Question 35

**cytoplasm **

Answer 35

a jelly-like substance located in the cell where all of the internal organelles can be found. The cytoplasm consists primarily of water and supports the cell and its organelles.

Question 36

**cytoskeleton **

Answer 36

organelles that are the internal “bones” of the cell. They exist in thick and thin tubules.