This was a question posed by a viewer on the popular South Korean television show, Curiosity Heaven, which translates to “a paradise for curiosity”. The program has been airing since the 1990s, where producers conduct experiments or consult experts to find answers to the most bizarre questions in life.
Regarding the question of whether an ant would die if it jumped off a skyscraper, Curiosity Heaven actually conducted an experiment to investigate. They took ants to the rooftop of the 63 Building, a 63-story structure standing 449 meters tall in Seoul, and dropped them:
Would the ants die from falling off this building?
Unfortunately, the recording of this episode is no longer available online for us to review. Some viewers only have vague memories of it, stating that the ants were dropped from the 63rd floor, but Curiosity Heaven had no way to retrieve them to confirm whether they were alive or dead.
Thus, this mystery continues to pique the curiosity of many. It even reached the United States, with a different version of the question in the “Ask the Van” section of the Physics Department at the University of Illinois: “If I drop an ant from the top of the Empire State Building, will it be killed on impact, or will the air resistance safely carry it to the ground?”
There is also an entire thread on Reddit in r/askscience discussing this question. However, we don’t really need to repeat the experiment of taking an ant to the 63rd floor of a building to confirm its survival status.
Perhaps, this could even provoke a strong reaction from the People for the Ethical Treatment of Animals (PETA). Therefore, let’s work with a bit of theory here to see if physics can indeed kill an ant falling from the 63rd floor.
It Depends on the Final Velocity of Free Fall
To understand the extent of damage from a free fall for an ant, we need to evaluate the impact force when it lands. Essentially, when you drop an ant from a high building, two forces act on it.
- The first is the force of gravity, which depends on gravitational acceleration (9.8 N/kg on Earth) and the mass of the ant.
- The other force is air resistance. The air resistance increases with the ant’s velocity during the fall and always acts in the opposite direction of its motion.
If we assume the ant falls straight down, the equation for the total forces acting on it will be:
Ignoring constants like ρ (density of air), A (cross-sectional area of the ant), and C (drag coefficient depending on shape), we see that as the velocity v increases, at some threshold, air resistance will balance out gravity. At that point, the total force acting on the ant will equal zero. The ant will fall with a constant velocity, which we call terminal velocity.
Terminal velocity is defined as the steady speed of an object when falling through a gas or liquid. The larger the weight and size of an object, the greater its terminal velocity will be.
This means that when it hits the ground, it will generate a larger reaction force. If the object is a living organism, a higher velocity means a lower chance of survival, and vice versa.
When skydiving and in free fall, a person can reach terminal velocity of about 200 km/h after 15 seconds.
For example, when a person skydives and falls freely, they can reach a terminal velocity of about 200 km/h after 15 seconds and a fall distance of 450 meters. Not deploying the parachute at this speed would certainly result in death.
A cat, with a smaller body, can only reach a terminal velocity of 97 km/h. The distance it travels is only 18-21 meters. Therefore, statistics show that the survival rate of a cat falling from the 7th floor and higher is the same, as they all reach terminal velocity.
In fact, there was a cat that fell from the 32nd floor of a building onto the streets of New York and only suffered broken ribs and a punctured lung. For cats, this injury is equivalent to just 2 days in the hospital before they can go home.
Rats have an even lower terminal velocity. John Burdon Sanderson Haldane, an English biologist, claimed that you could drop a rat down a mine shaft thousands of meters long. Upon reaching the bottom, it would only experience mild shock and then immediately scurry away.
Why can cats survive a fall from the 32nd floor?
Haldane stated that any organism smaller than a rat could survive a free fall from any height. This is because air resistance increases proportionally with the surface area of the moving object.
“Divide the length, width, and height of an animal by 10, its weight will decrease to one-thousandth, but its surface area will only decrease to one percent. Therefore, the drag force in the case of a small object can be ten times greater than the thrust force,” Haldane wrote.
Ants Will Not Die
In the case of an ant, the Ask the Van section of the University of Illinois Physics Department indicates that it has a very low terminal velocity, not exceeding 2 m/s, equivalent to 7.2 km/h. At this terminal velocity, air resistance can easily lift the ant and slow its speed upon landing.
The physical impact on the ant’s body is therefore negligible. It will still live and get up to walk around as usual.
On a windy day, even the air currents could overcome gravity and blow the ant back up.
This is also a common phenomenon for small objects with low terminal velocities like dust or mist. They can often remain suspended in the air indefinitely without ever touching the ground.
It should be noted that whenever an ant reaches terminal velocity, height is no longer a factor. Thus, the survival rate of an ant in free fall from the 63rd floor is essentially equivalent to that of falling from a tree to the ground.
A German television program, Die Sendung mit der Maus, conducted an experiment to test this, and you really don’t need to understand German to see the results:
What would happen if you dropped an ant from a high-rise building to the ground?
In the experiment, the ants were dropped from a relatively high distance but immediately got up and walked away. One reason for this is that ants have an exoskeleton made of chitin.
The sturdiness of the chitin layer not only protects ants from falls from heights but also helps them lift heavy objects and defend against attacks from predators. This is in stark contrast to vertebrate animals like us, which have skeletons inside their bodies and need to be protected by layers of soft tissue.
Ants have an exoskeleton made of chitin.
Additionally, studies have shown that ants do not have pain receptors. This means they do not feel any pain like humans and other higher animals do.
Therefore, a fall from the 63rd floor to the ground for an ant may simply be a delightful journey through the air. It would cause the ants no trouble, except for having to find their way home. So, this might be a bit more reassuring for PETA, right?
