If you grip an egg between your fingers and then release it, what will occur? Will it ascend to the ceiling? Absolutely not! It will descend to the ground and likely break open. Why? That’s correct. It’s all due to a small force known as gravity.
Thanks to gravity, we have a secure footing on the ground. Without gravity, we might float directly into outer space. Instead, the Earth attracts us towards its center at all times, keeping us on the ground.
Every object with mass exerts a gravitational attraction on everything surrounding it. That force is determined by the masses of the objects. Objects with a large mass, such as the Earth, exert a strong gravitational pull on the objects near them, such as humans and animals.
In addition to attracting other objects towards it, the Earth also accelerates those objects as they approach the ground. In other words, objects speed up as they get closer to the Earth. More importantly, the laws of science inform us that all objects—regardless of their mass—gain velocity at the same rate as they fall.
Italian scientist Galileo Galilei calculated the rate at which objects fall. According to his calculations, an object that is dropped falls to the ground at a rate of 9.8 meters per second, squared.
But how can that be? It seems counterintuitive based on our experience with the world around us. For example, if you hold a feather in one hand and a brick in the other and drop them at the same time, they won’t hit the ground at the same time. Will they?
Which will hit first? If you said the brick, you’re right! But why is that? If gravity causes objects to fall towards the Earth at the same rate, then why will the brick hit the ground long before the feather?
The answer lies in another scientific concept: air resistance. Air is present all around us. Those air molecules push against each other and against other objects. They provide an upward force of friction against anything that is falling. Galileo also discovered that the more dense something is, the less it’s affected by air resistance. Objects that are less dense will be slowed down more by air resistance.
This explains why a feather will fall to the ground very slowly when dropped. On the other hand, a brick will fall quickly—as if there was no air around it. Scientists who have tested these theories will tell you that, if you drop a feather in a vacuum (a container with no air), it will fall at the same rate as the brick!
Isn’t that fascinating? Think about the last time you dropped something. Was it a piece of paper? A set of keys? A tennis ball? Air resistance would have a different effect on each of these items. Which one do you think would fall the fastest?
Give it a try
We hope today’s feathery Wonder really piqued your interest! If you’re up for more, grab a friend or family member and check out these other enjoyable activities:
- Observe firsthand how objects with different densities and air resistance fall at different rates. Take a feather, a spoon, and various other objects. Write them down on a piece of paper and make a prediction about which objects will fall the fastest. Then, put your predictions to the test. Drop each item by pushing it off the edge of a table. Ensure that each item falls from the same height. Which objects fall the fastest? Were your predictions correct? Did you encounter any surprising results?
- Imagine a life without gravity. Initially, it might seem enjoyable to float around in space whenever you please. However, would it eventually become tiresome? How would your daily life change? How would you participate in sports, take a shower, or eat a bowl of cereal? Ponder upon the differences these activities would have in a gravity-free world. Then, write a short story about what life would be like. How would you adapt? What kind of inventions would be necessary to make life more normal? Enjoy exploring the possibilities of a life without the physical force we often take for granted!
- Up for a challenge? Go online and learn how to replicate Galileo’s experiment to calculate acceleration due to gravity. Make sure you have all the necessary supplies before you begin. It’s always a good idea to seek assistance from an adult. You’ll need to utilize your scientific and mathematical skills to attempt to recreate Galileo’s process. It’s truly remarkable how he was able to draw conclusions using simple materials and basic experiments, without the aid of modern technology. Would you have liked to be a scientist during Galileo’s time? Why or why not?
Wonder Sources
- http://www.physicsclassroom.com/mmedia/newtlaws/efar.cfm (accessed 12 Sept. 2020)
- https://www.khanacademy.org/science/physics/newton-gravitation/gravity-newtonian/v/would-a-brick-or-feather-fall-faster (accessed 12 Sept. 2020)
- http://www.infoplease.com/cig/science-fair-projects/some-objects-fall-faster-others.html (accessed 12 Sept. 2020)
- http://www.physics4kids.com/files/motion_gravity.html (accessed 12 Sept. 2020)
FAQ
1. How does the weight of a feather affect its falling speed?
The weight of a feather does not significantly affect its falling speed. In a vacuum, where there is no air resistance, all objects fall at the same rate regardless of their weight. This is known as the principle of equivalence. However, in the Earth’s atmosphere, feathers experience air resistance, which slows down their fall. The lighter weight of a feather means that it has a larger surface area compared to its mass, resulting in more air resistance. As a result, feathers fall slower than heavier objects like rocks.
2. Does the shape of a feather affect how fast it falls?
Yes, the shape of a feather can affect its falling speed. Feathers are typically lightweight and have a large surface area, which means they experience more air resistance compared to denser objects. The shape of a feather can determine how air flows around it, affecting the amount of drag it experiences. Feathers with a streamlined shape, such as those of birds, are designed to reduce drag and enhance flight efficiency. This streamlined shape allows them to fall faster compared to feathers with irregular shapes or those that are not as aerodynamic.
3. Can feathers reach terminal velocity when falling?
Yes, feathers can reach terminal velocity when falling in the Earth’s atmosphere. Terminal velocity is the maximum velocity an object can reach when falling, when the gravitational force pulling it downward is balanced by the air resistance pushing against it. However, the terminal velocity of a feather is much slower than that of denser objects due to its larger surface area and lower mass. Feathers have a feather-like structure that causes turbulence in the air, increasing drag and preventing them from reaching high speeds during freefall.
4. Are there any factors that can affect a feather’s falling speed?
Yes, several factors can affect a feather’s falling speed. The density of the air can influence the amount of air resistance a feather experiences, as denser air creates more drag. The shape and size of the feather also play a role, as feathers with a larger surface area and irregular shapes experience more air resistance. Additionally, external forces such as wind or other air currents can affect a feather’s falling speed by either slowing it down or speeding it up. Overall, while the weight of a feather does not significantly impact its falling speed, various factors related to its shape, size, and the surrounding environment can influence how fast it falls.
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