Scuba Flashcards
Underwater objects appear how much closer?
25%
Underwater objects appear how much larger?
1/3
As you descend what colors disappear first?
Reds and oranges
How much denser is water than air?
800x denser
How much faster does sound move in water?
4x faster
Water conducts heat away from your body ____ times faster than air does?
25x faster
When should you wear thermal protection?
Always
Water stratifies into layers by temp. what is the name of the boundary?
Thermocline
What is the primary cause of waves?
Wind
What forms surf?
The bottom of the wave slows causing the wave to break
What is the back and forth movement of water caused by waves passing overhead called?
Surge
Tides can affect what three things?
Depth, current, visibility
What 2 things cause most permanent ocean currents?
- The sun warming ocean water at the equator
- The earth’s rotation
What direction do rip currents flow compared to shore?
Perpendicular to shore
Where should you swim to get out of a rip current?
Parallel to shore
How do we measure wave height?
From the crest to the trough
How do we measure wave length?
Crest to crest
Long shore currents can be created by what four things?
- Wind
- Tides
- Waves
- Nearby ocean currents