GED Science 3

Question 1

What is the primary cause of ocean tides on Earth?

Accepted Answer

The gravitational pull of the Moon (and Sun)

Answer

Tides are primarily caused by the gravitational pull of the Moon on Earth's oceans. The Sun also contributes but to a lesser degree. The Moon's gravity creates bulges of water on the sides of Earth facing toward and away from the Moon.

Question 2

How do scientists use the half-life of radioactive isotopes to determine the age of rocks and fossils?

Accepted Answer

By comparing the ratio of parent to daughter isotopes in a sample

Answer

Radioactive isotopes decay at a known constant rate (half-life). By measuring the ratio of remaining parent isotope to daughter product, scientists calculate how long the decay has been occurring.

Question 3

What process drives the movement of tectonic plates?

Accepted Answer

Convection currents in Earth's mantle

Answer

Convection currents in the semi-molten mantle drive plate movement. Hot material rises, spreads, cools, and sinks, creating a conveyor-belt-like motion that moves the plates above.

Question 4

The Hertzsprung-Russell (H-R) diagram classifies stars based on which two properties?

Accepted Answer

Temperature and luminosity (brightness)

Answer

The H-R diagram plots stars by surface temperature (x-axis, hot on left) versus luminosity/brightness (y-axis). This reveals patterns including the main sequence, giants, supergiants, and white dwarfs.

Question 5

What happens at a convergent plate boundary where oceanic crust meets continental crust?

Accepted Answer

The oceanic crust subducts beneath the continental crust, forming mountains and volcanoes

Answer

Oceanic crust is denser than continental crust, so it subducts (sinks) beneath the continental plate. This creates deep ocean trenches, volcanic mountain ranges, and earthquakes.

GED Practice Test

GED Practice Test

GED Science 3