Which instrument measures gravity changes from point to point on the surface and was adapted from World War I technology?

Which instrument measures gravity changes from point to point on the surface and was adapted from World War I technology?

• A. Gravimeter
• B. Torsion Balance
• C. Magnetometer
• D. Seismometer

Answer: (B)

To map gravity variations across the surface, you need a device that is extremely sensitive to small gravitational forces and can translate those tiny forces into a measurable signal as you move from one location to another. The torsion balance achieves this by suspending a small mass or bar on a very fine fiber; the gravitational pull from nearby rocks and subsurface structures creates a torque that twists the fiber slightly. By measuring the resulting angular deflection, you obtain the local gravity value, and repeating this at different points reveals gravity changes across the area. This instrument’s design and sensitivity come from early 20th-century engineering and were refined from World War I-era technology, later repurposed for precise gravity surveying. Other options measure different things—gravimeters gauge gravity at a single point, magnetometers track magnetic fields, and seismometers detect ground motion—so they don’t specifically map surface gravity changes the way a torsion balance does.

To map gravity variations across the surface, you need a device that is extremely sensitive to small gravitational forces and can translate those tiny forces into a measurable signal as you move from one location to another. The torsion balance achieves this by suspending a small mass or bar on a very fine fiber; the gravitational pull from nearby rocks and subsurface structures creates a torque that twists the fiber slightly. By measuring the resulting angular deflection, you obtain the local gravity value, and repeating this at different points reveals gravity changes across the area. This instrument’s design and sensitivity come from early 20th-century engineering and were refined from World War I-era technology, later repurposed for precise gravity surveying. Other options measure different things—gravimeters gauge gravity at a single point, magnetometers track magnetic fields, and seismometers detect ground motion—so they don’t specifically map surface gravity changes the way a torsion balance does.