Why does the Cartesian diver sink when the bottle is turned upside down?

  • Context: High School 
  • Thread starter Thread starter frensel
  • Start date Start date
  • Tags Tags
    Cartesian
Click For Summary
SUMMARY

The Cartesian diver experiment using a Coca Cola bottle and an eyedropper demonstrates principles of buoyancy and pressure. When the bottle is turned upside down, the eyedropper sinks and does not float again due to the trapped air inside the dropper, which alters its buoyancy. The air pressure inside the bottle remains equal to atmospheric pressure, indicating that the mechanism behind the diver's behavior is related to the air volume in the eyedropper rather than external pressure changes. This phenomenon highlights the importance of understanding buoyancy in fluid dynamics.

PREREQUISITES
  • Understanding of buoyancy principles
  • Basic knowledge of fluid dynamics
  • Familiarity with pressure concepts
  • Experience with simple scientific experiments
NEXT STEPS
  • Research the principles of buoyancy in fluids
  • Explore the relationship between air pressure and volume using Boyle's Law
  • Investigate the effects of fluid density on buoyancy
  • Conduct experiments with different types of divers to observe variations in behavior
USEFUL FOR

Students, educators, and science enthusiasts interested in physics, particularly those exploring concepts of buoyancy and fluid mechanics.

frensel
Messages
20
Reaction score
0
Hi,

I follow the instruction in wikipedia to make a Cartesian diver (Coca Cola bottle + eyedropper), and it works well. I press the bottle, the eyedropper sinks; I release, it floats.

However, if I turn the bottle upside down, the eyedropper sinks and it never floats again. That means the buoyancy of the eyedropper is somewhat changed but I cannot understand the mechanism. If the buoyancy of the eyedropper decreases, the air pressure inside the bottle should increase, but it seems that it is not the case. I can open the bottle and the air pressure inside the bottle is equal to the atmospheric pressure, the eyedropper still sinks.

Can anyone repeat the experiment and explain why it happens? Thank you!
 
Physics news on Phys.org
Perhaps some air came out of the dropper when you turned it around.
 

Similar threads

Undergrad Modeling a Bottle Rocket: Analyzing the Maximum Altitude
  • · Replies 4 ·
Replies
4
Views
6K
High School Why do some heats of matches go down first in a Cartesian diver experiment?
  • · Replies 1 ·
Replies
1
Views
2K
Why do we store open bottles of hydrogen mouth down?
  • · Replies 3 ·
Replies
3
Views
3K
Undergrad Pressure in Gases: Boiling Water in a Can Explained
  • · Replies 3 ·
Replies
3
Views
2K
High School Why does atmospheric pressure not keep liquids inside upside down cups?
  • · Replies 3 ·
Replies
3
Views
2K
How High is the Water in the Bottle Based on Fluid Dynamics?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Calculating Air Pressure of Upside-Down Cup in Bathtub
  • · Replies 4 ·
Replies
4
Views
5K
What Is the Cartesian Diver Experiment?
  • · Replies 4 ·
Replies
4
Views
16K
High School Why does pressure in an enclosed container go up under the sea?
  • · Replies 14 ·
Replies
14
Views
8K
High School Why are there no bubbles in a pipette when pressure is released?
  • · Replies 1 ·
Replies
1
Views
1K