Free General Science (5436) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the General Science (5436) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What role does a scientific theory play in the study of natural phenomena?

   1. A.It explains phenomena and can support predictions.Correct answer: A
   2. B.It records observations without explaining them.
   3. C.It becomes a law once enough evidence is collected.
   4. D.It fixes results that cannot be revised by new evidence.

   Explanation: The National Academies states, "Scientific theories provide explanations aimed at illuminating the nature of particular phenomena, predicting future events, or making inferences about past events." A theory offers an evidence-based explanation and can support predictions. It is not merely a record, does not become a law, and remains open to revision.

   Reference: Science and Engineering Practices in K–12 Classrooms — Scientific theories

2. 2Which particle count determines the atomic number of an element?

   1. A.Neutrons in the nucleus
   2. B.Protons in the nucleusCorrect answer: B
   3. C.Electrons outside the nucleus
   4. D.Protons plus neutrons in the nucleus

   Explanation: NIST states, "The one feature that defines an atomic element is its atomic number, that is, the number of protons it has in its nucleus." Atomic number identifies the number of protons, not the mass number or electron count.

   Reference: The Periodic Table: It’s More than Just Chemistry and Physics — Atomic number

3. 3Which organelle packages molecules processed by the endoplasmic reticulum for transport out of the cell?

   1. A.Golgi apparatusCorrect answer: A
   2. B.Ribosome
   3. C.Mitochondrion
   4. D.Nucleus

   Explanation: "The Golgi apparatus packages molecules processed by the endoplasmic reticulum to be transported out of the cell." The Golgi modifies and packages material; ribosomes make proteins and mitochondria convert food energy.

   Reference: MedlinePlus Genetics: What Is a Cell? — Golgi apparatus

4. 4What causes the changing phases of the Moon seen from Earth?

   1. A.Earth's shadow covers different parts of the Moon each week.
   2. B.The Moon produces more light during some parts of its orbit.
   3. C.Observers see different portions of the Moon's sunlit half as it orbits Earth.Correct answer: C
   4. D.The Sun illuminates a different fraction of the Moon each week.

   Explanation: "how much we are able to see of that illuminated half changes as the Moon travels through its orbit." Changing viewing geometry reveals different amounts of the sunlit half; ordinary phases are not caused by Earth's shadow.

   Reference: NASA Moon Phases — Overview From Space

5. 5A researcher reruns another team's analysis using its original data and code under the same analysis conditions. What is the researcher examining?

   1. A.Computational reproducibilityCorrect answer: A
   2. B.Independent replication
   3. C.Sampling representativeness
   4. D.Measurement calibration

   Explanation: The National Academies defines the term: "Reproducibility means obtaining consistent results using the same input data, computational steps, methods, and conditions of analysis". The same data and analysis are used here, rather than newly collected data.

   Reference: 10 Things to Know About Reproducibility and Replicability — Item 1, page 1

6. 6A neutral carbon atom has 6 protons, 6 neutrons, and 6 electrons. Which neutral atom is a different isotope of carbon?

   1. A.7 protons, 7 neutrons, 7 electrons
   2. B.6 protons, 7 neutrons, 6 electronsCorrect answer: B
   3. C.6 protons, 7 neutrons, 5 electrons
   4. D.6 protons, 6 neutrons, 6 electrons

   Explanation: NIST states, "Each atom can have several different versions, known as isotopes, in which there are different numbers of neutrons in the nucleus." The second neutral carbon atom must retain six protons and six electrons but have a different neutron count.

   Reference: The Periodic Table: It’s More than Just Chemistry and Physics — Isotopes

7. 7Which structure uses genetic instructions to assemble proteins?

   1. A.Lysosome
   2. B.RibosomeCorrect answer: B
   3. C.Plasma membrane
   4. D.Golgi apparatus

   Explanation: "Ribosomes are organelles that process the cell’s genetic instructions to create proteins." Ribosomes carry out protein synthesis; the other structures have different functions.

   Reference: MedlinePlus Genetics: What Is a Cell? — Ribosomes

8. 8During a lunar eclipse, which body casts a shadow on the Moon?

   1. A.The Sun
   2. B.Mars
   3. C.The Moon
   4. D.EarthCorrect answer: D

   Explanation: "Earth’s shadow falls upon the surface of the Moon" A lunar eclipse occurs when Earth lies between the Sun and Moon and its shadow reaches the Moon.

   Reference: NASA Eclipses and the Moon — Lunar Eclipse Basics

9. 9A new study does not replicate an earlier finding. What conclusion is warranted from that result alone?

   1. A.The earlier finding is conclusively refuted.
   2. B.The difference requires further investigation.Correct answer: B
   3. C.The new study must contain scientific fraud.
   4. D.The original conclusion is necessarily correct.

   Explanation: The National Academies cautions, "A successful replication does not guarantee that the original scientific results of a study were correct, nor does a single failed replication conclusively refute the original claims." A single failure cannot settle whether the original claim is false; differences in methods, uncertainty, or other factors require investigation.

   Reference: 10 Things to Know About Reproducibility and Replicability — Item 4, page 1

10. 10In a nuclear fusion reaction, what happens to the nuclei?

    1. A.A heavy nucleus splits into smaller nuclei.
    2. B.Two light nuclei combine to form a heavier nucleus.Correct answer: B
    3. C.Electrons move between atoms without nuclear change.
    4. D.A nucleus releases energy by emitting a gamma ray only.

    Explanation: DOE states, "Fusion occurs when two atoms slam together to form a heavier atom, like when two hydrogen atoms fuse to form one helium atom." Fusion joins nuclei; fission splits a nucleus.

    Reference: Fission and Fusion: What Is the Difference? — Fusion