A cylindrical tank with a radius of 3 meters and a height of 7 meters is filled with water. A solid metal sphere with a radius of 2 meters is completely submerged in the tank. What is the new water height in the tank?
This real-world physics scenario combines everyday engineering with fundamental principles of displacement. As digital interest grows in home design, industrial applications, and sustainable water management, understanding how submerged objects affect liquid levels in cylindrical containers remains a practical question for designers, homeowners, and STEM learners alike.


Why This Question Is Rising in US Conversations

Understanding the Context

Amid growing interest in smart living spaces and resource efficiency, questions about submerged volumes in cylindrical tanks surface frequently online. With rising awareness of water conservation and space optimization, the simple math behind volume displacement ties directly into larger conversations about infrastructure and everyday science. Platforms tracking trending technical queries show this topic gaining traction, particularly in housing forums, educational content, and DIY home improvement spaces.


How Does Submerging a Metal Sphere Affect Tank Water Levels?

The tank holds a fixed volume of water until the sphere is submerged. Because the tank’s base area determines how much water rises for every cubic meter displaced, the sphere’s volume directly increases the upward water height. Unlike irregularly shaped objects, the sphere’s symmetrical geometry simplifies volume calculations, making accurate predictions both feasible and reliable.

Key Insights


Calculating the New Water Height Step-by-Step

Let’s begin with the tank’s volume:
Volume = π × r² × h = π × (3 m)² × 7 m = 63π cubic meters

The sphere has a radius of 2 m, so its volume is:
Volume = (4/3)π × (2 m)³ = (32/3)π cubic meters

Adding the sphere to the tank results in total liquid volume:
Total volume = 63π + (32/3)π = (189/3 + 32/3)π = (221/3)π m³

Final Thoughts

Now solve for new height:
π × (3)² × h_new = (221/3)π
9h_new = 221/3
h_new = (221 / 27) ≈ 8.185 meters

The water now rises to approximately 8.18 meters—just under 8.