NAEP Science 3 — Questions and Answers
Question 1: The half-life of carbon-14 is about 5,730 years. If a sample originally had 80 grams of carbon-14, approximately how much remains after 11,460 years?
- 40 g
- 20 g (Correct answer)
- 10 g
- 5 g
Correct answer: 20 g
After one half-life (5,730 yr) 40 g remain; after two half-lives (11,460 yr) half of that—20 g—remains.
Question 2: Lichens are considered a mutualistic partnership between fungi and:
- Mosses
- Photosynthetic algae or cyanobacteria (Correct answer)
- Soil bacteria
- Ferns
Correct answer: Photosynthetic algae or cyanobacteria
In a lichen, the fungus provides structure and absorbs water while the algae or cyanobacteria produce food through photosynthesis, benefiting both partners.
Question 3: Newton's Third Law states that for every action there is an equal and opposite reaction. Which scenario best demonstrates this law?
- A heavier object falls faster than a lighter one
- A rocket expels gas downward and accelerates upward (Correct answer)
- Friction slows a sliding book to a stop
- A pendulum swings back and forth at constant speed
Correct answer: A rocket expels gas downward and accelerates upward
A rocket pushes exhaust gases backward (action), and those gases push the rocket forward (reaction), perfectly illustrating Newton's Third Law.
Question 4: The process by which plants convert carbon dioxide and water into glucose and oxygen using light energy is called:
- Cellular respiration
- Fermentation
- Photosynthesis (Correct answer)
- Transpiration
Correct answer: Photosynthesis
Photosynthesis uses light energy captured by chlorophyll to convert CO₂ and H₂O into glucose, releasing O₂ as a byproduct.
Question 5: Tectonic plates move because of convection currents in which layer of Earth?
- Inner core
- Outer core
- Mantle (Correct answer)
- Crust
Correct answer: Mantle
Heat-driven convection currents in the semi-fluid mantle create drag forces that move the rigid tectonic plates of the crust.
Question 6: A student compares the brightness of two flashlights with identical batteries. Flashlight A appears brighter. Which measurement would best explain why?
- The voltage of each battery
- The current flowing through each bulb (Correct answer)
- The mass of each flashlight
- The color of each lens
Correct answer: The current flowing through each bulb
Brightness (power output) in a bulb depends on current; higher current through the filament produces more light and heat.
Question 7: Which property distinguishes a mixture from a pure chemical compound?
- Mixtures always contain gases
- Mixtures can be separated by physical means (Correct answer)
- Mixtures have a fixed boiling point
- Mixtures always appear homogeneous
Correct answer: Mixtures can be separated by physical means
The components of a mixture retain their individual properties and can be separated using physical processes such as filtration, distillation, or magnetism.
NAEP Science 3
The half-life of carbon-14 is about 5,730 years.
If a sample originally had 80 grams of carbon-14, approximately how much remains after 11,460 years?