Air resistance is a kind of friction (a force that opposes motion) that occurs between air and another object. It is the force that the object experiences as it passes through the air. Air resistance and gravity are the two fixed forces of nature that move on any object on Earth.
What is Air Resistance for Kids?
Air resistance, also known as drag, is friction (a force that opposes motion) between air and another object. It is the force that the object experiences as it passes through the air. Air resistance and gravity are the two fixed forces of nature that move on any object on Earth.
For example, when a plane flies through the air, the air particles press against it, making it harder for the aircraft to move.
When you see a feather fall, air resistance significantly affects it because it has lots of surface area for the air to contact with and lacks the weight to overcome the air resistance.
Air resistance for kids affects many parts of the world around us! From the wind that slows us while we’re riding bikes or driving in cars to how our papers flutter and drift when they fall to the floor, air resistance is a part of life. If we study this phenomenon, we’ll better know how it works!
What is Friction
Before we dive deeper into air resistance, we must understand the general concept on which air resistance is based! Friction is a force that opposes motion. It happens when two objects make contact, creating a resistance of motion.
For example, if you try to slide a toy car across a smooth piece of wood, it will move quickly because the wheels are not generating much friction against the smooth surface. On the other hand, if you slide the same toy car across a thick carpet, you will need to push the car much more to make it move, stopping far more quickly. A consequence of increased friction.
Friction can be both good and bad for the objects involved; if the two objects are a glass of water on a table, their static friction is good because it stops the glass from sliding off the table. But, on the other hand, if the objects are your trainers and the ground causes them to wear out, that isn’t good!
Here are a few other examples:
Examples of Friction
There are positive and negative examples of friction that can happen to us in our daily lives. Here are those examples!
Positive examples of friction
- Putting our foot down to slow down a scooter or bike.
- Rubbing your hands to warm up in winter creates the warmth we are all familiar with!
- Writing and drawing by causing the pencil to generate friction against the paper.
Negative examples of friction
- When we fall on the ground and scrape our knees, our skin creates friction on the floor.
- Air resistance slows down how far you can kick a ball.
- Friction can wear away the soles of our shoes, making them eventually unusable!
There are also two types of friction – static and kinetic. Static friction happens when two objects aren’t moving, and kinetic friction happens between two things that are. An example of static friction is when you are walking– when your feet settle against the ground and slide, that second of sliding is static friction! Another more accessible example is when you push a piece of furniture. An example of kinetic friction would be anything with wheels sliding across the ground, like a car or roller skates!
Who Discovered Air Resistance?
We all know air resistance has always existed, but the fact of the matter stands: who was the first person to point out this occurrence in our natural world? Well, the answer is much more straightforward than many may think! Air resistance was discovered by the famous and fabulous Italian scientist Galileo Galilei. Many call him the father of modern physics because of all his discoveries.
It’s said that around 1590, he went to the top of the Leaning Tower of Pisa, where he dropped many different objects. These were cannonballs, musket balls, wood, silver, and lots of other stuff I’m sure we all have lying around. When he dropped them, he ensured that one object was always heavier than the other but with the same size and shape. And he found they still hit the ground simultaneously, so heavier things wouldn’t fall faster than lighter ones.
He determined that gravity accelerates all things at the same rate and doesn’t matter their weight.
An early version of a parachute was found in an anonymous manuscript from the 1470s before Galileo started hurtling cannonballs off buildings. It wasn’t as good a design as parachutes are now, but it introduced the concept to artist-engineers of the times.
Then, a few years later, Leonardo da Vinci created an improved but improved design. Many credit him for falling using a ‘maximum drag decelerator’ (this would be a parachute).
Why not get your students to recreate Galileo’s experiment (probably without the cannonballs, but each to their own) so they can see the effect of gravity and air resistance for themselves? It would be a fun interactive activity for students to participate in that they’ll love and be beneficial for their learning. This way, they see the forces in action instead of just reading about them.
What Causes Air Resistance
Also known as ‘drag,’ air resistance is a force caused by air. The air particles hit the front of an object, causing it to slow down. The greater the surface area, the greater the number of air particles hitting the thing and the greater the overall resistance.
Two main things affect air resistance- the object’s speed and cross-sectional area. The faster an object goes, the more air resistance there’ll be. It’s the same for a large cross-sectional area; an increased area leads to increased air resistance.
What can be Affected by Air Resistance
Air resistance affects most of the world around us, but there are some undeniable examples that we can point out to show off exactly how air resistance works!
Examples of Air Resistance
Here are some examples of air resistance in everyday life.
- Wind. When the wind blows, it is sometimes difficult to walk through the air because the air resists your force and pushes you back against you.
- Parachute. When a skydiver jumps out of an airplane, they open a parachute. Air resistance causes them to parachute slowly to the ground.
- Bicycle. When you ride a fast bike, air resistance pushes you back.
- Airplane. When an aircraft is flying up in the air, the air particles hit the plane, making it more challenging to move through the air.
- Leaves. On a windy day, when you see leaves falling from a tree slowly, air resistance slows down their fall.
- Umbrellas. You know that annoying experience when it’s raining cats and dogs, and you put up your umbrella, but it’s tough to hold because of the wind? So what’s that, you say? So that’s air resistance, too? Yup.
Why not see if students can develop their examples of air resistance? A fun activity with them would be to list all the items they can think of that experience air resistance, then research each to discover how these items harness air resistance.
Air Resistance and Streamlining
Objects need to have a small surface area for things to move quickly and efficiently through air or water. Conversely, the bigger the surface area, the more excellent the resistance; objects must be streamlined to push against the air’s force.
Trains are designed to be streamlined so they can move quicker, getting you from one destination to the next! Even people can try and be simplified, like swimmers, for example. They maintain a streamlined shape during races to get through the water more quickly. But this is because of water rather than air resistance (hence, they are Can your students think of any more streamlined items to reduce air resistance?
One way of testing how streamlining works is to create paper airplanes. Get some pieces of paper, screw some up, turn some into planes, and then see which falls faster. Through this, you can see how having a streamlined shape affects how quickly you lose.
What are the Three Main Types of Air Resistance for Kids?
Air resistance, or drag, can be put into one of three categories; lift induced, parasitic, and wave. Each type of air resistance affects an object’s ability to stay up and the power it will need to keep it there.
- Lift-induced air resistance happens due to the creation of lift on a three-dimensional lifting body (wing or fuselage).
- Parasitic drag happens when a solid object moves through a fluid. This air resistance type comprises components like ‘form drag’ and ‘skin friction drag.’
- Wave drag occurs when an object scurries through a compressible fluid.
With these three types of drag, we can witness the different effects of air resistance and study the results to ensure we know how to best use air resistance to our advantage. It is how airplanes and other flying or driving crafts were created– by studying the three main types of air resistance to find the best to use!
5 Fun Facts about Air Resistance and Friction
- Because of air resistance, cyclists crouch low on their bikes to make them go faster! They also have streamlined cycling equipment so that air passes are more accessible, so it doesn’t slow them down.
- Because sports cars have a streamlined shape, they’ll go faster than other vehicles because they experience less air resistance.
- Because of air resistance, using a parachute slows your fall to around 12 mph, making a much safer landing.
- Friction can generate static electricity. You can see this when you rub a balloon against your head, and the friction causes your hair to stand up. Or you rub your feet along the carpet and give someone an electric shock.
- Due to air resistance, snowflakes that may weigh the same amount as a drop of water the same size fall slower because their shape is streamlined to allow them to glide down rather than fall.
Key Terms and Vocabulary About Air Resistance and Forces
Have a vocabulary quiz coming up in your science class? Here are some key terms and vocabulary words all about air resistance, streamlining, friction, and forces to help you study for that!
- Gravity – the force that brings things to the ground
- Air resistance – the friction between air and an object
- Water resistance – the friction between water and an object
- Friction – the resistance when two objects are rubbed together
- Galileo Galilei – the person who discovered air resistance
- Isaac Newton – the person who discovered gravity
- Acceleration – the rate that something increases in speed
- Kinetic – relating to, caused by, or producing motion
- Lubricant – a substance like oil or grease that, when on a surface, reduces friction
- Material – the substance used to create objects
- Motion – the act of moving
- Resistance – a force that opposes or slows down another force
- Streamlined – a shape designed to cause the least air resistance
- Surface area – a solid flat area