Getting Crabby at Semester's End

  • Thread starter holly
  • Start date
In summary, the conversation discusses the appearance of crabs in different types of water and lighting. It is noted that in deep water, the color red is absorbed, causing the crab to appear black. The question of which color light would make a blue crab appear black is also discussed, with suggestions of yellow or red being complementary colors to blue. A reference to a lecture on using lasers to communicate with submarines also provides insight into the colors of light that can penetrate deep water. Overall, the conversation highlights the complexity of color perception in different environments and the role of light absorption in determining the color of objects.
  • #1
holly
184
0
We are doing a chapter on color.

Q. A red crab very deep in water, where sunlight is dim, appears:
Orange?
Cyan?
Brown?
Red?
Black?

I have seen crabs, reddish crabs, in shallow water, and they looked tan or brown. But in deep water, I am unsure they would be brown. I know this has something to do with the color red getting absorbed as you travel down in seawater. However, the book is saying that the real color of seawater is greenish-blue, and I feel it is more a tea color, more greenish tan. So, I don't know.

Q. A blue crab will appear black when illluminated with:
Blue light?
Yellow light?
Light?
Cyan light?
None of these?

I think it's yellow...that's the complementary color of blue...but then again, doesn't that mean it would be white? So I would think it would be RED, perhaps, but that isn't a choice offered.

Thanks for any help.
 
Physics news on Phys.org
  • #2
Im not sure if this would be of any help but i went to lecture last week about using lasers to communicate with submeries. The prof. giving the lecture work for the navy during the cold war, and work not this lasers. He said that the only color laster he could use to communate with subs was blue. Thus a red crab (absorbs every wave length but red) should appear black/dark because their is not red light at the bottum of the sea. This is just an guess, but i hope it helps.
 
  • #3
holly said:
Q. A blue crab will appear black when illluminated with:
Blue light?
Yellow light?
Light?
Cyan light?
None of these?

I think it's yellow...that's the complementary color of blue...but then again, doesn't that mean it would be white? So I would think it would be RED, perhaps, but that isn't a choice offered.

The crab is blue because it only reflects blue light. Which of those is not blue? Blue is blue. Yellow does not have blue in it. "light" probably means white light, which includes blue. Cyan is blue. I think the answer is yellow.

You can go into MS Paint and check which colors have which components in them.
 
  • #4
holly said:
Q. A red crab very deep in water, where sunlight is dim, appears ...
... I know this has something to do with the color red getting absorbed as you travel down in seawater.
Yes, the seawater absorbs the color red. As you go deeper, the light will have less and less red. So the "red" crab--and the blood from that shark bite!--will appear black.
 
  • #5
Thx to all who answered, I appreciate it. I have one more "crab" question I'll post separately. What is it with these crabs?
 

Related to Getting Crabby at Semester's End

1. What are some common signs of feeling crabby at the end of the semester?

Some common signs of feeling crabby at the end of the semester include increased stress levels, irritability, difficulty concentrating, and lack of motivation.

2. How can I manage my stress during the end of the semester?

To manage stress during the end of the semester, it is important to prioritize tasks and create a schedule, take breaks and engage in self-care activities, and seek support from friends, family, or a therapist.

3. Why do I feel more irritable during the end of the semester?

Feeling irritable during the end of the semester is a common response to increased stress and pressure to perform well on exams and assignments. Lack of sleep and poor self-care habits can also contribute to irritability.

4. How can I stay motivated during the end of the semester?

To stay motivated, it is important to set realistic goals and break tasks into smaller, more manageable chunks. It can also be helpful to reward yourself for completing tasks and to remind yourself of the long-term benefits of finishing the semester strong.

5. What can I do to prevent feeling crabby at the end of the semester?

To prevent feeling crabby at the end of the semester, it is important to practice self-care throughout the semester, maintain a balanced schedule, and reach out for help if needed. It can also be helpful to set realistic expectations and to prioritize tasks to avoid feeling overwhelmed.

Similar threads

I Investigating a 3D Color Hue Phenomenon with Blender and Just Color Picker
    • Optics
Replies
2
Views
1K
B Question about Primary Colors -- Why Red-Green-Blue?
    • Classical Physics
Replies
6
Views
1K
Why does mixing blue and yellow create green?
    • Mechanics
Replies
3
Views
855
I The physics behind mixing coloured pigments (questions inside post)
    • Classical Physics
Replies
4
Views
944
Understanding colors (Lights And Optics)
    • Introductory Physics Homework Help
Replies
4
Views
1K
I Question about subtractive color mixing
    • Other Physics Topics
3
Replies
98
Views
7K
I Color Theory - What does blue + yellow make?
    • Classical Physics
Replies
21
Views
955
Electrolysis: Dark blue oxide from steel?
    • Chemistry
Replies
6
Views
1K
Cable color standards in the US
    • Electrical Engineering
Replies
5
Views
997
Can RGB LED simulate incandescent bulb 'glow'?
    • Electrical Engineering
Replies
3
Views
1K

Hot Threads

Recent Insights

Back
Top