OSAT – Science Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf.
1. Which statement best explains why the scientific method used in
elementary and secondary science education is generally described
as a process of inquiry rather than as a rigid sequence of steps?
A. Scientific investigations must always begin with a controlled
laboratory experiment and end with a universally accepted law.
B. Scientific inquiry involves asking questions, developing
explanations, gathering evidence, analyzing observations, and
revising explanations as warranted by evidence.
C. Scientific inquiry requires scientists to avoid prior knowledge
because previous information can bias all observations.
D. Scientific inquiry is primarily concerned with memorizing
established scientific facts before attempting practical
investigations.
Answer: B.
Scientific inquiry is an evidence-based and iterative process in which
,questions, hypotheses, observations, experimentation, analysis, and
explanations interact. Investigators may revise questions or
explanations when new evidence challenges an initial interpretation.
2. A teacher asks students to determine whether the amount of
sunlight affects the growth of bean plants. Four groups use identical
soil, containers, seed varieties, and watering schedules but expose
their plants to different amounts of light. Which variable is the
independent variable in this investigation?
A. Height of the bean plants at the end of the investigation
B. Type and amount of soil used in each container
C. Amount of sunlight provided to each group
D. Amount of water supplied to the plants
Answer: C.
The independent variable is the factor deliberately changed by the
investigator. In this experiment, students manipulate the amount of
sunlight while attempting to keep other relevant conditions constant.
3. A student measures the mass of an object three times and obtains
25.1 g, 25.2 g, and 25.1 g. A calibrated balance indicates that the
actual mass is 27.0 g. Which statement best characterizes these
measurements?
A. They are both precise and accurate.
B. They are accurate but not precise.
C. They are precise but not accurate.
D. They are neither precise nor reproducible.
,Answer: C.
Precision describes how closely repeated measurements agree with one
another, whereas accuracy describes how close a measurement is to the
accepted value. The measurements are tightly clustered but
substantially different from 27.0 g, making them precise but inaccurate.
4. During an investigation, students observe that a liquid changes
from clear to cloudy after another substance is added. They
conclude that a chemical reaction may have occurred. Which
observation would provide the strongest additional evidence
supporting that conclusion?
A. The liquid was contained in a transparent beaker.
B. The temperature of the mixture changed without external
heating or cooling.
C. The beaker was placed on a laboratory table.
D. The original liquid had a volume of 50 mL.
Answer: B.
An unexplained temperature change can provide evidence of an energy
change associated with a chemical reaction. Other observations
describe experimental conditions but do not directly provide comparable
evidence of chemical change.
5. Which property most directly distinguishes a physical change from a
chemical change?
A. A physical change always involves an increase in temperature.
B. A physical change changes the identity of the substance, whereas
, a chemical change does not.
C. A physical change generally alters form or state without
producing a new substance, whereas a chemical change produces
one or more new substances.
D. A chemical change can occur only when two solid substances are
mixed.
Answer: C.
Physical changes such as melting, freezing, cutting, or dissolving
generally do not alter the chemical identity of matter. Chemical changes
involve rearrangement of atoms that produces substances with different
chemical properties.
6. A sealed container holds a chemical reaction in which two
substances combine to form new products. If no matter enters or
leaves the container, what should happen to the total mass of the
system?
A. It should decrease because products usually have less mass than
reactants.
B. It should increase because chemical reactions create matter.
C. It should remain constant because matter is conserved in a
closed system.
D. It should become zero once the reactants are completely
consumed.
Answer: C.
The law of conservation of mass states that matter is neither created
Questions And Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf.
1. Which statement best explains why the scientific method used in
elementary and secondary science education is generally described
as a process of inquiry rather than as a rigid sequence of steps?
A. Scientific investigations must always begin with a controlled
laboratory experiment and end with a universally accepted law.
B. Scientific inquiry involves asking questions, developing
explanations, gathering evidence, analyzing observations, and
revising explanations as warranted by evidence.
C. Scientific inquiry requires scientists to avoid prior knowledge
because previous information can bias all observations.
D. Scientific inquiry is primarily concerned with memorizing
established scientific facts before attempting practical
investigations.
Answer: B.
Scientific inquiry is an evidence-based and iterative process in which
,questions, hypotheses, observations, experimentation, analysis, and
explanations interact. Investigators may revise questions or
explanations when new evidence challenges an initial interpretation.
2. A teacher asks students to determine whether the amount of
sunlight affects the growth of bean plants. Four groups use identical
soil, containers, seed varieties, and watering schedules but expose
their plants to different amounts of light. Which variable is the
independent variable in this investigation?
A. Height of the bean plants at the end of the investigation
B. Type and amount of soil used in each container
C. Amount of sunlight provided to each group
D. Amount of water supplied to the plants
Answer: C.
The independent variable is the factor deliberately changed by the
investigator. In this experiment, students manipulate the amount of
sunlight while attempting to keep other relevant conditions constant.
3. A student measures the mass of an object three times and obtains
25.1 g, 25.2 g, and 25.1 g. A calibrated balance indicates that the
actual mass is 27.0 g. Which statement best characterizes these
measurements?
A. They are both precise and accurate.
B. They are accurate but not precise.
C. They are precise but not accurate.
D. They are neither precise nor reproducible.
,Answer: C.
Precision describes how closely repeated measurements agree with one
another, whereas accuracy describes how close a measurement is to the
accepted value. The measurements are tightly clustered but
substantially different from 27.0 g, making them precise but inaccurate.
4. During an investigation, students observe that a liquid changes
from clear to cloudy after another substance is added. They
conclude that a chemical reaction may have occurred. Which
observation would provide the strongest additional evidence
supporting that conclusion?
A. The liquid was contained in a transparent beaker.
B. The temperature of the mixture changed without external
heating or cooling.
C. The beaker was placed on a laboratory table.
D. The original liquid had a volume of 50 mL.
Answer: B.
An unexplained temperature change can provide evidence of an energy
change associated with a chemical reaction. Other observations
describe experimental conditions but do not directly provide comparable
evidence of chemical change.
5. Which property most directly distinguishes a physical change from a
chemical change?
A. A physical change always involves an increase in temperature.
B. A physical change changes the identity of the substance, whereas
, a chemical change does not.
C. A physical change generally alters form or state without
producing a new substance, whereas a chemical change produces
one or more new substances.
D. A chemical change can occur only when two solid substances are
mixed.
Answer: C.
Physical changes such as melting, freezing, cutting, or dissolving
generally do not alter the chemical identity of matter. Chemical changes
involve rearrangement of atoms that produces substances with different
chemical properties.
6. A sealed container holds a chemical reaction in which two
substances combine to form new products. If no matter enters or
leaves the container, what should happen to the total mass of the
system?
A. It should decrease because products usually have less mass than
reactants.
B. It should increase because chemical reactions create matter.
C. It should remain constant because matter is conserved in a
closed system.
D. It should become zero once the reactants are completely
consumed.
Answer: C.
The law of conservation of mass states that matter is neither created
