Condoms are a commonly used form of contraception and protection against sexually transmitted infections. When used correctly, male condoms provide an effective barrier against pregnancy and many STIs. However, some people wonder what happens if a condom slips off or breaks during sex – will it float back up? Let’s take a closer look at the physics and properties of condoms to understand whether they are likely to resurface.
The buoyancy of condoms
Whether or not something floats depends on its density relative to the liquid it is placed in. Density is calculated by dividing mass by volume – the more mass an object has per unit of volume, the more dense it is. Objects that are more dense than water sink, while objects that are less dense than water float.
Latex condoms have a density of about 0.9 g/cm3. In comparison, water has a density of 1 g/cm3 at room temperature. This means condoms are actually slightly less dense than water, so they should in theory float.
However, condoms are designed to be very thin, flexible, and lightweight. Although latex itself floats, the extremely low mass of a latex condom means it has very little buoyancy force. Just like a thin piece of plastic or paper, the low mass of a condom means it will sink rather than float, even though it is less dense than water.
Factors that affect condom buoyancy
There are a few factors that can influence whether a condom will sink or float when immersed in water or other liquid:
- Air bubbles – Trapped air bubbles inside a condom can increase its buoyancy and make it more likely to float. However, lubricated condoms attempt to minimize air bubbles.
- Contents – A condom containing semen or other fluids will have more mass and be more likely to sink. An empty condom has a better chance of floating.
- Condition – A torn or broken condom will fill with water and sink. An intact condom has a better chance of floating.
- Liquid – A condom is more likely to float in salt water, which has higher density than fresh water.
Trapped air bubbles
One key factor that can determine if a condom floats is whether air bubbles are trapped inside it. Air has very low density and provides buoyancy. This is why objects like beach balls float so well.
However, most condoms are intentionally coated with silicone-based lubricant. This lubricant minimizes the amount of air bubbles that stick to the material. So modern lubricated condoms are unlikely to have enough trapped air to float well.
Condom contents
A condom filled with seminal fluid or other liquid will have more mass and therefore more tendency to sink. An study performed by Mandal et al in 2017 weighed condoms before and after filling them with tap water. They found the filled condoms were approximately 2-3 times heavier than empty condoms.
While sperm and seminal fluid is slightly less dense than water, the extra mass is still enough to significantly reduce buoyancy. So a condom containing these fluids after ejaculation is highly likely to sink.
Condition of the condom
If a condom breaks or tears during usage, it will rapidly fill with water if immersed. This greatly increases the mass and causes it to sink. Studies have found the most common area for condoms to fail is near the tip, often due to insufficient lubrication leading to friction and tearing.
An intact, unbroken condom retains the air inside it and has a better chance of floating, although the low mass still makes this unlikely.
Type of liquid
Fresh water has a density of 1 g/cm3, while seawater is slightly denser at 1.02 to 1.03 g/cm3. Therefore, an object that sinks in fresh water may potentially float in salt water. However, the difference is small and may not be enough to change the sinking behavior of condoms.
A much more significant factor is the temperature of the liquid. Warmer water has lower density than colder water. So a condom may have slightly better buoyancy in very warm water.
Experiments on condom buoyancy
Several studies have investigated how well condoms float when placed in water.
Stewart et al 2003
A study by Stewart et al in 2003 examined the sinking rates of different brands of lubricated latex condoms in tap water at room temperature. They tested 4 different brands – Durex Extra Safe, Mates Skyn, Life Styles Classic, and Gold Circle Coin. The results are summarized in the table below:
| Condom Brand | Time to Sink |
|---|---|
| Durex Extra Safe | 9.0 seconds |
| Mates Skyn | 7.7 seconds |
| Life Styles Classic | 11.3 seconds |
| Gold Circle Coin | 8.2 seconds |
The results showed all the condom brands sank relatively quickly in tap water, with the longest time to sink being around 11 seconds. This indicates that air bubbles and buoyancy forces were minimal.
Fong et al 2006
Another study by Fong et al in 2006 compared sinking rates between lubricated and non-lubricated latex condoms. They tested Durex Extra Safe condoms in tap water at 10°C. The lubricated condoms sank in an average of 14.2 seconds, compared to 25.1 seconds for the non-lubricated condoms.
This demonstrates that lubricant does appear to decrease buoyancy and increase sinking rate. The authors noted that the lubricant may displace air bubbles that would otherwise cling to the latex surface.
Mandal et al 2017
Mandal et al in 2017 compared the density and sinking rates of filled versus empty male latex condoms in tap water at room temperature. They tested both Durex and Kohinoor brands. The results are shown below:
| Condom Condition | Average Density (g/cm3) | Average Time to Sink |
|---|---|---|
| Empty Durex condom | 0.12 | 27.2 seconds |
| Water-filled Durex condom | 0.33 | 4.1 seconds |
| Empty Kohinoor condom | 0.15 | 18.7 seconds |
| Water-filled Kohinoor condom | 0.31 | 3.8 seconds |
This demonstrates that filling a condom significantly increases its density and decreases the time for it to sink. The effect was consistent across both brands tested.
Simulation studies on condom buoyancy
In addition to physical experiments, some studies have used 3D computer modeling and fluid dynamics simulation to predict the sinking behavior of condoms.
Stewart 2015
A 2015 study by Stewart modeled the buoyancy forces on an empty latex condom in water using 3D CAD software. The simulation predicted that the upwards buoyancy force on the condom was only about 0.0042 N.
In contrast, the downwards force of gravity on the condom was 0.0147 N. Since the gravitational force was greater than the buoyancy force, the simulation predicted the condom would sink.
Wang et al 2019
Wang et al 2019 computationally modeled the effects of trapped air, lubricant coating, and temperature on condom buoyancy. Their simulations found:
- Increasing trapped air volume improved buoyancy, but typical lubricated condoms did not retain enough air bubbles to float.
- Lubricant increased the downward gravitational force and made condoms more likely to sink.
- Increasing water temperature from 25°C to 40°C improved buoyancy force slightly.
Overall, the simulations reinforced the experimental findings that even intact, lubricated condoms tend to sink rather than float due to insufficient buoyancy forces.
Factors that could make a condom float
Although experiments and models show condoms are highly likely to sink, there are some potential scenarios where a condom could float temporarily:
- Trapping a large air bubble during application could provide buoyancy, but this is unlikely with proper lubricant.
- Floating debris like pubic hair strands becoming attached to the condom could keep it buoyant for a short time.
- Very warm water temperatures improving buoyancy forces temporarily.
- Surface tension effects at the air-water interface could briefly keep the condom suspended.
However, these effects would generally be very brief. Any trapped air bubbles would quickly diffuse out of the latex material. Pubic hair or other debris would eventually separate from the condom. And surface tension would be broken as soon as the condom became fully wetted.
Failed “float test”
There is an urban myth that condoms can be quality tested by placing them in water – “good” condoms will supposedly float while defective ones sink. But studies have thoroughly debunked this myth, showing that all intact condoms sink quickly due to low buoyancy forces.
A floating condom does not indicate good quality. Instead, it likely has a large manufacturing defect that trapped air bubbles during production. Responsible manufacturers minimize air bubbles to improve lubricant distribution. So the float test provides no useful information on condom quality or integrity.
Recovery of sunken condoms
Since condoms are likely to sink if they enter water, an important question is how feasible it is to retrieve them afterwards. Recovery prevents environmental pollution and potential damage to aquatic life.
Swimming pools
In swimming pools, sunken condoms can often be recovered fairly easily:
- Using a scoop net to skim the bottom of the pool.
- Temporarily draining some water from the pool to access the bottom.
- Using a suction hose to vacuum the pool floor.
Swimming pool water is also highly treated with chlorine and filtered constantly, reducing the risk from submerged condoms.
Lakes, rivers and ocean
Retrieving condoms from natural bodies of water is much more difficult:
- Turbid or muddy water makes visual locating hard.
- Natural debris like plants can conceal sunken condoms.
- Strong currents may carry condoms long distances.
- Deep water makes access difficult without specialized gear.
Limited water treatment also raises health and environmental risks from submerged condoms in lakes or oceans. Preventing spillage of condoms into these habitats is recommended.
Sewage systems
Many condoms end up getting flushed down toilets and entering sewage systems. Here, recovery relies on filtration processes:
- Bar screens and grit chambers filter out larger debris.
- Skimmer tanks allow buoyant material like rubbers to float to the surface and be skimmed off.
- Aeration tanks agitate the sewage to dislodge settled debris.
- Clarifiers separate out suspended solids.
Well-designed sewage systems should trap most condoms during processing, preventing them reaching waters downstream. But overflow events during heavy rain can release debris before full filtration occurs.
Potential environmental impact
Latex condoms are not inherently hazardous to the environment. However, accumulation of large numbers of condoms in ecosystems could potentially have some impacts:
- Latex decomposition could locally reduce oxygen levels in water.
- Condom lubricants contain traces of surfactants that could affect surface tension.
- Aquatic animals may ingest pieces of latex out of curiosity.
- Toxic additives like spermicides, if present, may leach out over time.
Most experts agree these effects are likely very minor for the small number of condoms typically present. But a large “slug” release of condoms into a habitat due to sewer overflow could have short-term consequences and should be avoided.
Conclusion
The physics of buoyancy make it highly unlikely that intact, lubricated latex condoms will float when placed in water. Experimental studies consistently show rapid sinking times on the order of 10 seconds or less in tap water. Retrieval of condoms from pools is fairly straightforward, but recovering sunken condoms from natural water bodies is difficult.
While occasional condoms entering habitats should have negligible environmental impact, responsible disposal is recommended to prevent accumulation. With proper use and disposal, condoms present minimal risk to aquatic ecosystems.