8th Grade Science Test 1

Question 1

measures the pull of gravity on an object

Answer 1

weight

Question 2

a good scientific experiment includes

Answer 2

several constant factors and one variable

Question 3

substances composed of only one type of atom

Answer 3

elements

Question 4

in order for soil to drain well and not retain excess water, it must contain

Answer 4

sand

Question 5

humus is formed as a result of

Answer 5

decomposition

Question 6

the type of soil that contains a mixture of sand, silt, clay, and humus

Answer 6

loam

Question 7

primary plant food element found in the ashes of burned fruits

Answer 7

potassium

Question 8

a substance having a pH of 10 would be

Answer 8

basic

Question 9

a theory that has never been proven false

Answer 9

law

Question 10

a fertilizer bag labeled 10-8-14 would contain 10% of the element

Answer 10

nitrogen

Question 11

measures the amount of matter in an object

Answer 11

mass

Question 12

plants that have short stems, few leaves, and a pale green color need the plant food element

Answer 12

nitrogen

Question 13

the plant food element that a farmer should apply when his crop begins to ripen

Answer 13

phosphorus

Question 14

nitrates are formed by

Answer 14

lightning, nitrifying bacteria, nitrogen-fixing bacteria

Question 15

legumes allow nitrogen-fixing bacteria to form swellings called ___ on their roots

Answer 15

nodules

Question 16

measures how tightly packed matter is

Answer 16

density

Question 17

a sensible explanation to a scientific problem

Answer 17

hypothesis

Question 18

substances composed of two or more elements bonded together

Answer 18

compounds

Question 19

the primary plant food elements

Answer 19

nitrogen
phosphorus
potassium

Question 20

when scientists perform experiments, they record facts and information called

Answer 20

data

Question 21

the study of soil

Answer 21

pedology

Question 22

the study of matter and movement of God’s physical creation

Answer 22

science

Question 23

to express acidity and basicity of substances, chemists use the

Answer 23

pH scale

Question 24

the upper surface of ground water

Answer 24

water table

Question 25

soil and porous rock that cannot hold any more water are said to be

Answer 25

saturated

Question 26

List the six steps of the scientific method.

Answer 26

1. State the problem.
2. Gather information about the problem.
3. Formulate a hypothesis.
4. Test the hypothesis by designing and performing an experiment.
5. Record and analyze any changes during the experiment.
6. State the conclusions.

Question 27

any soil material primarily derived from from living organisms

Answer 27

organic

Question 28

any soil material primarily derived from nonliving matter

Answer 28

mineral

Question 29

breakdown of organisms

Answer 29

decompose

Question 30

substance composed of decayed organisms’ particles

Answer 30

humus

Question 31

reusing old materials

Answer 31

recycling

Question 32

process that breaks rocks down into soil

Answer 32

weathering

Question 33

top 2 to 6 inches of soil

Answer 33

topsoil

Question 34

layer of solid rock below the soil

Answer 34

bedrock

Question 35

the substance of the physical world

Answer 35

matter

Question 36

an area of ground water collected in a layer of rock or soil

Answer 36

aquifer

Question 37

a “self-pumping” well

Answer 37

artesian well

Question 38

the upward movement of water through a tiny space in response to surface tension

Answer 38

capillarity

Question 39

the most basic units of matter

Answer 39

atoms

Question 40

the air pockets that are found in the soil

Answer 40

pore spaces

Question 41

Describe the nitrogen cycle, why it is important to plants, an done way in which nitrogen compounds are formed.

Answer 41

The nitrogen cycle is the movement of nitrogen from the air to the soil to be used by plants and then returned to the atmosphere to be used again.
The nitrogen cycle is important because plants cannot use the form of nitrogen that is in air unless it is combined with other elements to form certain compounds.
Nitrogen compounds (specifically nitrates) are formed when lightning causes nitrogen and oxygen to form compounds that are carried to the soil by rain.
Nitrogen compounds are formed by nitrogen-fixing bacteria