1. A team of scientists uses the Hubble Space Telescope to search for evidence of planets orbiting distant stars. Which kind of investigation are they carrying out?
A. Laboratory experiment
B. Controlled experiment
C. Observational study Correct
D. Constructing a model
Explanation
Using the Hubble Space Telescope to observe distant stars without manipulating variables is an observational study. Laboratory and controlled experiments involve variable control, while modeling uses simulations. This method collects data from natural phenomena.
2. Which question would be appropriate for an observational study?
A. Which type of glass best resists scratching?
B. Which type of rock dissolves fastest when exposed to acid rain?
C. What is the brightest star that can be seen from Earth? Correct
D. How does the mass of a toy car affect how fast it rolls down a track?
Explanation
Identifying the brightest star visible from Earth requires only observation, fitting an observational study. Questions about glass, rocks, or toy cars involve controlled experiments to test variables. This question relies on passive data collection.
3. A scientist wants to determine how the speed of flowing water affects the size of sediment particles it can carry. The scientist places a mix of sediment particles in the bottom of a trough and runs water through the trough. The scientist varies the speed of the water and measures the sizes of the particles that the water carries away. Which type of investigation is the scientist using?
A. Controlled experiment Correct
B. Field study
C. Observational study
D. Computational model
Explanation
The scientist manipulates water speed and measures particle sizes in a controlled setting, indicating a controlled experiment. Field studies occur in natural environments, observational studies avoid manipulation, and computational models use simulations. This tests a specific variable systematically.
4. Which question would be appropriate for an observational study?
A. Which type of metal conducts electricity best?
B. Does adding salt to water affect how fast the water evaporates?
C. What types of rocks are found at a convergent boundary? Correct
D. How does the mass of an object affect the strength of its gravitational field?
Explanation
Observing rock types at a convergent boundary involves collecting data without manipulation, suitable for an observational study. Testing conductivity, evaporation, or gravity requires controlled experiments. This focuses on natural geological observation.
5. Numerous experiments have confirmed that if the distance between a light source and an observer is doubled, the intensity of the light as viewed by the observer decreases by a factor of four. Which type of scientific statement is this?
A. Inference
B. Hypothesis
C. Law Correct
D. Theory
Explanation
This consistent, experimentally verified relationship is the inverse square law, a scientific law. Hypotheses are untested, theories explain broader phenomena, and inferences are conclusions from data. The statement predicts a precise pattern.