Deep-Ocean Exploration Technology · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Exploring the deep ocean: submersibles, sonar, and other worlds

Science · Ocean Life · ages 13-14
Name ______________________   Date ____________

  1. What tool do scientists use to map the seafloor from a ship far above?

    • A telescope that magnifies light underwater
    • Sonar, which uses sound pulses that bounce off the seafloor
    • A microphone that listens for fish sounds

  2. What is the difference between Alvin and an ROV?

    • Alvin carries scientists inside it; an ROV is controlled from a ship with no one aboard
    • An ROV carries scientists inside it; Alvin is controlled from a ship with no one aboard
    • Both carry scientists, but Alvin is faster

  3. Scientists have mapped the entire ocean floor at high resolution.

    Circle one:   True   False

  4. Which set of conditions makes the deep ocean harder to explore than the Moon's surface?

    • Crushing pressure, freezing cold, and total darkness
    • Too much sunlight and heat
    • Low gravity that makes movement difficult

  5. Why can't a ship talk to a deep-sea ROV the way Mission Control talks to astronauts?

    • ROVs have no way to send any signal once submerged
    • Deep-sea water amplifies radio signals until they overload
    • Radio waves fade out fast underwater, so ROVs use sound signals instead

  6. About what percent of the ocean floor has been mapped in high-resolution detail using sonar? Type just the number.

    Oceanfloor25Moonsurface100

    Answer: ______________

  7. Mia says, 'We understand the deep ocean better than the Moon because water is easier to explore than space.' What is wrong with her statement?

    • The Moon has never been mapped at all
    • Nothing, her statement is correct
    • It's backwards: the Moon's surface is mapped in far more detail than our ocean floor

  8. Which moon is the target of NASA's Europa Clipper mission, sent to study an ocean hidden beneath ice?

    • Mars, which has ice caps at its poles
    • Europa, a moon of Jupiter with a liquid ocean under its icy shell
    • our own Moon, which has no ocean
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Exploring the deep ocean: submersibles, sonar, and other worlds W1-mt_kKxbPHi5Db-s1

  1. Sonar, which uses sound pulses that bounce off the seafloor · Sonar times how long a sound pulse takes to bounce back to figure out the depth.
  2. Alvin carries scientists inside it; an ROV is controlled from a ship with no one aboard · Alvin is a crewed submersible. An ROV is remotely operated and has no one on board.
  3. False · Only about 25% of the ocean floor has been mapped in that much detail so far.
  4. Crushing pressure, freezing cold, and total darkness · Pressure, cold, and darkness all get worse the deeper you go, and none of those affect the Moon's surface the same way.
  5. Radio waves fade out fast underwater, so ROVs use sound signals instead · Radio does not travel far through water, so ROVs and submersibles rely on slower sound signals.
  6. 25 · Sonar surveys have covered close to a quarter of the seafloor at high resolution.
  7. It's backwards: the Moon's surface is mapped in far more detail than our ocean floor · Pressure, cold, darkness, and slow communication have kept ocean mapping behind Moon mapping, not ahead of it.
  8. Europa, a moon of Jupiter with a liquid ocean under its icy shell · Europa's ice shell hides a liquid water ocean, which is why scientists study it for signs it could support life.
Worksheet · LightMySky