Introduction to the Feather and Coin Experiment
When gravity was not defined, everything was suspected to fall depending on its mass. According to Aristotle, massive objects fall more rapidly than the tiny ones. On studying this concept, Galileo Galilei had a doubt and started thinking differently. He performed the feather and coin experiment and found two different cases: when the feather and coin were dropped within air resistance, they dropped correctly according to their mass with a free fall motion, proving Aristotle right but another result was detected for vacuum. Finally, he concluded that at a place where no air resistance is acting, the two objects had the same effect of gravitational acceleration.
These conclusions are the bases for the development of classical mechanics. Every fundamental study of gravity includes this acceleration which is consistent throughout the fall. In many of the school’s curriculum, this experiment has been kept as an important practical and theoretical heading to make students grasp the concept of free fall.
Historical Background: Galileo’s Insights into Free Fall
Feather and coin experiment is just an evidence-less thought involving the dropping of two objects (feather and coin) by Galileo from the Leaning Tower of Pisa for the visualization of gravitational acceleration and its effect on objects. Sadly, no evidence of such activity has been found. Somewhere, inclined plane experiments have been found. He used a smooth inclined plane and balls of various masses to observe their motion and used water clocks or counting beats to note the time. He observed that the falling rate was different for each of them. Thus, he concluded that it was air resistance which made different timing of fall. His theory for vacuum challenged Aristotle’s concept and concluded that any kind of objects fall at the same time when no air resistance is acting on them. This conclusion was a huge mark for the development of Newton’s universal laws.
Understanding the Effects of Air Resistance on Falling Objects
Air resistance occurs with the presence of air. The air tries to drag objects upward but the gravitational pull is downward. Therefore heavier objects are less influenced by air and come directly towards the center of gravity but lighter objects like feather, cotton can be easily shifted by air. Hence, air resistance is a very important factor for falling motion.
Experiments done freely on earth thus could not be regarded as the correct laws to define free fall. Thus Galileo and other scientists like commander David Scott performed the experiments to get some different results. Two experiments concluded that the free fall motion of an object is the same without the air. These findings are regarded as the cornerstone of physics.
Conducting the Experiment: Materials and Procedure
Materials required:
- A transparent vacuum chamber
- A vacuum pump
- A feather
- A coin
- A mechanism to release both objects simultaneously
- A high-speed camera or observation window
Procedure:
- Insert feather and coin in vacuum.
- Hold them by some methods so that they are released at the same time.
- Seal the chamber and use the vacuum pump to remove the air to create vacuum.
- Drop them at the same instant.
- Note the time of fall using a stopwatch.
- Repeat the experiment, now by filling air inside the chamber for comparison.
The findings of Galileo can be obtained at conclusion.
Setting Up the Vacuum Environment
Creating a vacuum environment is very important for removing all the air present and checking the experiment under valid conditions. The vacuum chamber must be airtight so that the air cannot re-enter. The vacuum pump must be able to overcome the pressure inside the chamber to make air resistance negligible.
Modern vacuum pumps can achieve pressures as low as required and make the research of purpose more precise. It is important to guard the pressure using a vacuum gauge so that the desired vacuum level is maintained throughout the experiment.
Observing the Behavior of the Feather and Coin in Air vs. Vacuum
In the presence of air lighter objects like feathers are swept away by air and hence fall slowly but the coin drops quickly. This can be easily observed. When the experiment is done in a vacuum, both travel at the same rate also falling together. This observation is very surprising and interesting to learn.
The observations and findings of the experiment in a vacuum helps to draw the nature of acceleration due to gravity. It strongly defeats the concept that mass affects the free fall of objects.
Analyzing the Results: The Role of Gravitational Acceleration
The main theme to carry out this experiment was to catch up to the consistent acceleration in vacuum. The conclusion of this experiment illustrates that acceleration due to gravity is affected by various factors like latitude, altitude, mass of the celestial objects, presence of air etc. Planets and other outer space may have different air conditions which directly affects the gravitational pull. As a comparison, Mercury has the value of ‘g’ 3.7 m/s^2 and Jupiter has got g = 24.79 m/s^2. Mercury is very close to the sun and certainly affected by solar winds. On the other hand, Jupiter has no solid surface and no air resistance. Hence, the free fall in mercury is slower but affected by air resistance while it is very fast in Jupiter but is consistent for every particle.
This experiment is in accordance with Newton Laws of motion. Gravity got its true description after this demonstration. Thus, it has a great role in analyzing acceleration due to gravity and free fall at different points of space.
Real-World Applications: From Classroom Demonstrations to Lunar Experiments
This experiment is very simple to carry out but reveals wonderful secrets of nature. Thus it is practically demonstrated in all physics studies. Since physics is taken as a tough course, a visual example can make the study easier. In advanced labs, modern vacuum chambers are used which are more accurate and give precise measurement of ‘g’ on planets and other regions, creating a virtual environment.
A higher case study is made by conducting experiments in more extreme environments. For example, the demonstration made by astronaut David Scott was performed on the lunar surface without atmosphere. This was a huge credit to Galileo.
Common Misconceptions About Gravity and Free Fall
When acceleration due to gravity is not studied properly, people get wrong ideas on motion. Thus, to avoid all the confusions, these visual experiments are performed. Some of the false concept on gravity and free fall are as follows:
- Heavier objects fall faster: This is the belief of Aristotle which has already been proven false by Galileo. Mass of an object has no relation with the free fall in vacuum.
- Gravity acts differently on different objects: Gravity always acts in its own way. Its impact differs according to the distance, mass of the object (for the presence of air resistance), altitude. Latitude etc. Thus, the nature of gravity remains the same every time but is influenced by other physical factors.
- Objects fall at constant speed: In the influence of gravity, objects fall with a uniform acceleration which is the result of rapid change in speed. For example, the speed changes by 9.8 m/s every second on earth and by 3.7 m/s every second on mercury. This rate of change of speed gives birth to a uniform acceleration.
Implications of the Feather and Coin Experiment in Physics Education
For the conceptual development of laws of motion and everything around us, feather and coin must be implied in physics curriculum. A confused mind gets a clear idea about gravity after seeing the demonstration of this experiment. In pointwise discussion, some of the points may be discussed as follows:
- Engagement:The interesting observations draw the interest of a student. Its simple nature can quickly catch the attention. A lengthy and complex method can make anyone perplexed.
- Conceptual clarity: It can clarify the concept of gravity and acceleration due to gravity. One can also use this method to calculate the value of ‘g’ at different conditions.
- Critical thinking: A curiosity can arise in a student’s mind about the air resistance and gravity. Some critical ideas may come to the mind seeing this phenomenon which can have important consequences.
- Historical context: The development of classical mechanics from Aristotle to Galileo and historic iconic experiments on the moon can be presented with this experiment. The history of Newton’s law can also be provided through it.
Teachers can use this experiment to raise curiosity in a productive mind, clarify all myths, and map a road for further exploration in classical physics.
Conclusion
Feather and coin are an important tale of physics leaving its blueprint as a susceptor for gravity. The message provided by this experiment was taken as reference by Newton to develop his laws of motion and law of universal gravitation. The practical experiment is as interesting as studying the history of the pioneer theory. A physics student should be familiar with the topic while describing acceleration due to gravity. Hence, a hands-on session is equally important to make anyone understand gravity. Hence this experiment is a solid work based on a powerful hypothesis and strong results.
References
SARDELIS, D. A. (1981). The Law of Free Fall: Myth and Historical Reality. Fundameta Scientiae, 2(2), 163-183.
CARMAN, A. (2012). EXPERIMENT. DANCE MAGAZINE, 86(9), 34-+.
Chiu, Y. J., & Chen, F. Y. (2012). Students’ misunderstanding of Galileo’s experiment on the leaning tower of Pisa. In Proceeding of The International Conference New Perspectives in Science Education, Italy (pp. 1-5).
Drake, S. (1973). Galileo’s discovery of the law of free fall. Scientific American, 228(5), 84-93.
Naylor, R. H. (1974). Galileo and the problem of free fall. The British Journal for the History of Science, 7(2), 105-134.
https://www.exploratorium.edu/snacks/falling-feather
