Why Do Some Heavy Objects Float and Other Heavy Objects Sink?

Whether an object sinks or floats in a fluid (liquid or gas), depends on several variables:
1. The density of the object in a fluid. (Density is the ratio of the object’s mass to volume.)
2. The density of the fluid (gas or liquid) the object is floating in.
3. If the density of the object is greater than the density of the fluid, the object sinks.
If the density of the object is equal to or is less than the density of the fluid, the object floats.
Does the Bowling Ball In The Diagram Sink or Float?
The diagram shows the bowling ball on the bottom of the container of water. But, assuming it is being held in place on the bottom, will it float when released?
Think!
1. If the density of the bowling ball is greater than the density of the water it is submersed in, it will not float. If the ball’s density is equal to or less than the density of the water, the ball will float.
2. Calculate the density of the bowling ball using this formula: density = mass ÷ volume
d = 5.5 kg ÷ 4.5 liters
= 1.2 kg/1liter or 1.2 kg per 1 liter
3. Calculate the density of the displaced water using the same density formula: density = mass ÷ volume
d = 4.5 kg ÷ 4.5 liters
= 1.0 kg/1liter or 1.0 kg per 1 liter
Answer: The density of the bowling ball is greater than the density of the displaced water, thus the bowling ball will not float. The bowling ball sinks in this water.
Challenge: Do All Bowling Balls Sink? How Does the Weight of a Ball Affect Its Ability to Float
This Book Has Experiments for These Topics: Astronomy, Biology, Chemistry, Earth Science, and Physics 