STAAR Success - Grade 8 Science - Practice #2
Read each question carefully. Choose the best answer to each question. For open-response questions, determine the best answer to the question.
Question 1a
Li-Fi technology uses light waves for data transmission. Which of the following is a limitation of Li-Fi compared to Wi-Fi?
Lower data transfer speeds
Susceptibility to electromagnetic interference
Limited range due to line-of-sight requirements
Higher energy consumption
Question 1b
Perovskite solar cells have gained attention in renewable energy research. What is a significant advantage of perovskite solar cells compared to traditional silicon-based solar cells?
Lower production cost
Higher efficiency in all conditions
Longer lifespan
Established manufacturing processes
Question 1c
Explain how the design of the suspension bridge helps distribute the forces of tension and compression during high winds. Use the labeled components in the diagram to support your explanation.
Source: ScienceDirect
Question 2a
Graphene, a single layer of carbon atoms arranged in a hexagonal lattice, exhibits remarkable properties. Which of the following is NOT a characteristic of graphene?
High electrical conductivity
Exceptional tensile strength
Biodegradability
Transparency
Question 2b
Which process ensures genetic diversity in sexually reproducing organisms?
Mitosis
Cloning
Crossing-over during meiosis
Asexual reproduction
Question 2c
Explain how a beneficial mutation can affect an organism's survival and lead to evolution over time.
Question 2d
Which type of wave can travel through a vacuum?
Sound wave
Seismic wave
Water wave
Light wave
Group 3
Source: MPR News
Question 3a
Describe two possible consequences of the observed polar ice cap melting for global systems. Use evidence from the images to support your answer.
Question 3b
Which statement best describes potential energy?
It depends only on the speed of an object.
It is energy due to the position or condition of an object.
It cannot be converted to kinetic energy.
It is the energy an object has while in motion.
Question 3c
A skier at the top of a hill has potential energy. Describe what happens to this energy as the skier moves down the hill.
Group 4
This question has two parts. First, answer Part A. Then, answer Part B.
Question 4a
Part A: A car is moving at a constant speed of 20 m/s. What can you conclude about the net force acting on the car?
The net force is zero.
The net force is directed forward.
The net force is directed backward.
The net force is equal to the car’s weight.
Question 4b
Part B: Which scenario would change the conclusion in Part A?
The car accelerates to 30 m/s.
The car continues to move at a constant speed of 20 m/s.
The car is on a frictionless surface.
The car is driving in a circular path.
Question 4c
A 10 kg object accelerates at 2 m/s². What is the net force acting on it?
5 N
10 N
20 N
30 N
Group 5
This question has two parts. First, answer Part A. Then, answer Part B.
Question 5a
Part A: A student observes that a wave has a wavelength of 2 meters and a frequency of 5 Hz. What is the speed of the wave?
2.5 m/s
10 m/s
20 m/s
25 m/s
Question 5b
Part B: If the frequency of the wave in Part A doubles while the speed remains constant, what happens to the wavelength?
It doubles.
It halves.
It remains the same.
It decreases to one-fourth of its original value.
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