Polar Oceans and World Climate · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

How Polar Oceans Shape Earth's Climate

Science · Polar Regions · ages 9-11
Name ______________________   Date ____________

  1. Which reflects more sunlight back to space: white sea ice or dark ocean water?

    • Dark ocean water
    • White sea ice
    • They reflect the same amount

  2. A scientist gently pours very cold, salty water into a tank of warmer, fresher water. What does the cold, salty water do?

    • It sinks to the bottom, because it is denser than the warmer water
    • It floats on top, because cold water is lighter
    • It stays in the middle and stops moving

  3. The Southern Ocean around Antarctica has very little life because it is so cold.

    Circle one:   True   False

  4. Look at the graph. About how many out of 100 sunlight rays does the ice reflect back to space?

    White ice80Dark ocean10

    Answer: ______________

  5. A scientist measures ocean water near the North Pole and finds it is colder and saltier than the water around it. What will this water most likely do?

    • Rise to the surface and spread out
    • Stay in place and freeze completely
    • Sink and start flowing along the ocean floor

  6. Upwelling near the Southern Ocean brings water from deep in the ocean up to the surface. What does this deep water carry that helps ocean life?

    • Nutrients
    • Sand
    • Ice

  7. If more sea ice melts and is replaced by dark ocean water, what is most likely to happen to the amount of heat Earth absorbs from the sun?

    • There will be no change, because ice and water reflect sunlight the same way
    • Earth will absorb less heat, because dark water reflects more sunlight
    • Earth will absorb more heat, because dark water reflects less sunlight

  8. Maria says the ocean's conveyor belt of currents is powered by wind alone. What is she missing?

    • The currents actually never move
    • Sinking cold, dense polar water also drives the currents
    • Only warm water can sink and drive currents
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Answer key

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

How Polar Oceans Shape Earth's Climate W1-mt_g1qgxmlJQ2-s1

  1. White sea ice · White ice acts like a mirror for sunlight, while dark water absorbs it as heat.
  2. It sinks to the bottom, because it is denser than the warmer water · Cold, salty water is denser than warmer, fresher water, so it sinks to the bottom of the tank.
  3. False · It is actually one of the most productive seas on Earth, because upwelling brings nutrients to the surface.
  4. 80 · The bar for ice reaches about 80, meaning ice reflects most of the sunlight that hits it.
  5. Sink and start flowing along the ocean floor · Colder, saltier water is denser, so it sinks and joins the deep currents of thermohaline circulation.
  6. Nutrients · The rising deep water carries nutrients that feed tiny ocean plants, which the rest of the food web relies on.
  7. Earth will absorb more heat, because dark water reflects less sunlight · Losing reflective ice means more dark water is exposed, and dark water absorbs more sunlight as heat.
  8. Sinking cold, dense polar water also drives the currents · Thermohaline circulation is driven by dense polar water sinking, not just by wind.
Worksheet · LightMySky