Students investigated the effect of wingspan length on the flight of several toy gliders that had different wingspans. For each trial, they measure and the amount of time in the air using a stopwatch.
Which of the following was the dependent variable in this investigation?
- A. The wingspan
- B. The flight distance
- C. The stopwatch
- D. The tape measure
Correct Answer & Rationale
Correct Answer: B
In this investigation, the dependent variable is the outcome that is measured in response to changes in the independent variable. Flight distance (B) reflects how far something travels, which depends on the conditions set by the experiment. Wingspan (A) is an independent variable if it is being manipulated to see its effect on flight distance. The stopwatch (C) is a tool used to measure time and does not represent a variable in the experiment. Similarly, the tape measure (D) is an instrument for measuring distance, not a variable being tested. Thus, flight distance is the key outcome that reflects the effects of the experiment.
In this investigation, the dependent variable is the outcome that is measured in response to changes in the independent variable. Flight distance (B) reflects how far something travels, which depends on the conditions set by the experiment. Wingspan (A) is an independent variable if it is being manipulated to see its effect on flight distance. The stopwatch (C) is a tool used to measure time and does not represent a variable in the experiment. Similarly, the tape measure (D) is an instrument for measuring distance, not a variable being tested. Thus, flight distance is the key outcome that reflects the effects of the experiment.
Other Related Questions
Which TWO of the following are true statements about hurricanes?
- A. They are typically over 160 kilometers, or 100 miles, in diameter.
- B. They form over cold water in Earth's polar regions and move slowly.
- C. They develop quickly and usually last for less than 30 minutes.
- D. They can have sustained wind speeds that are over 200 kilometers per hour.
Correct Answer & Rationale
Correct Answer: A, D
Hurricanes are vast systems, often exceeding 160 kilometers (100 miles) in diameter, making option A true. Additionally, they can reach sustained wind speeds over 200 kilometers per hour, confirming option D. In contrast, option B is incorrect as hurricanes form over warm waters, typically in tropical regions, not cold polar waters. Moreover, they do not move slowly; they can travel at significant speeds. Option C is also false; while hurricanes can develop rapidly, they generally last for several days, not just 30 minutes. Understanding these characteristics is crucial for recognizing the nature and impact of hurricanes.
Hurricanes are vast systems, often exceeding 160 kilometers (100 miles) in diameter, making option A true. Additionally, they can reach sustained wind speeds over 200 kilometers per hour, confirming option D. In contrast, option B is incorrect as hurricanes form over warm waters, typically in tropical regions, not cold polar waters. Moreover, they do not move slowly; they can travel at significant speeds. Option C is also false; while hurricanes can develop rapidly, they generally last for several days, not just 30 minutes. Understanding these characteristics is crucial for recognizing the nature and impact of hurricanes.
Which of the following is always true of a chemical change?
- A. Color, shape, or texture is altered.
- B. Mass is increased.
- C. A new substance is formed.
- D. Gas or vapor is generated.
Correct Answer & Rationale
Correct Answer: C
A chemical change always results in the formation of a new substance, which is a fundamental characteristic distinguishing it from physical changes. Option A is incorrect because while color, shape, or texture may change, these alterations do not confirm a chemical change unless a new substance is produced. Option B is misleading; mass is conserved in chemical reactions, so it does not necessarily increase. Option D, while often true (as gases can be produced), is not universally applicable; some reactions do not produce gas. Hence, the formation of a new substance is the definitive indicator of a chemical change.
A chemical change always results in the formation of a new substance, which is a fundamental characteristic distinguishing it from physical changes. Option A is incorrect because while color, shape, or texture may change, these alterations do not confirm a chemical change unless a new substance is produced. Option B is misleading; mass is conserved in chemical reactions, so it does not necessarily increase. Option D, while often true (as gases can be produced), is not universally applicable; some reactions do not produce gas. Hence, the formation of a new substance is the definitive indicator of a chemical change.
The speed of light in empty space, that is, a vacuum, is 300,000 km/s. The speed of sound in empty space is:
- B. greater than 0 but less than 300,000 km/s
- C. 300,000 km/s
- D. greater than 300,000 km/s
Correct Answer & Rationale
Correct Answer: A
The speed of sound requires a medium, such as air or water, to propagate; it cannot travel through a vacuum. Therefore, the speed of sound in empty space is effectively zero. Option B suggests that the speed of sound is greater than 0 but less than 300,000 km/s, which is incorrect because sound cannot exist in a vacuum. Option C states it is 300,000 km/s, which misrepresents sound's nature, as this speed is specific to light. Option D claims it is greater than 300,000 km/s, which is impossible since sound cannot travel in a vacuum at all. Thus, the only valid conclusion is that the speed of sound in empty space is zero.
The speed of sound requires a medium, such as air or water, to propagate; it cannot travel through a vacuum. Therefore, the speed of sound in empty space is effectively zero. Option B suggests that the speed of sound is greater than 0 but less than 300,000 km/s, which is incorrect because sound cannot exist in a vacuum. Option C states it is 300,000 km/s, which misrepresents sound's nature, as this speed is specific to light. Option D claims it is greater than 300,000 km/s, which is impossible since sound cannot travel in a vacuum at all. Thus, the only valid conclusion is that the speed of sound in empty space is zero.
Fossilized remains of prehistoric organisms are typically found in which of the following types of rock?
- A. Metamorphic rock
- B. Igneous rock
- C. Sedimentary rock
- D. Molten rock
Correct Answer & Rationale
Correct Answer: C
Fossilized remains are most commonly found in sedimentary rock, which forms from the accumulation of sediment and organic material in layers. This environment allows for the preservation of organisms. Metamorphic rock (A) forms under high pressure and temperature, altering existing rocks and typically destroying fossils. Igneous rock (B) is created from cooled magma or lava, which does not preserve organic material. Molten rock (D) refers to rock in a liquid state, which cannot contain fossils as it is not solidified. Thus, sedimentary rock is the ideal environment for fossil preservation.
Fossilized remains are most commonly found in sedimentary rock, which forms from the accumulation of sediment and organic material in layers. This environment allows for the preservation of organisms. Metamorphic rock (A) forms under high pressure and temperature, altering existing rocks and typically destroying fossils. Igneous rock (B) is created from cooled magma or lava, which does not preserve organic material. Molten rock (D) refers to rock in a liquid state, which cannot contain fossils as it is not solidified. Thus, sedimentary rock is the ideal environment for fossil preservation.