At-Home STEM Activities: How Birds Use Their Wings
This week we’re looking at different aspects of flight and ways that we can explore those at home.
As we learned on Monday and Tuesday, birds are able to fly using the Bernoulli Principle and aerodynamic flight. They flap their wings, moving the air beneath them and creating an area of lower pressure. This provides lift, allowing the birds to fly.
Of course, there is a bit more to it than that. Like most animals, birds have evolved so that their bodies match their behavior—flying birds have hollow bones and light beaks, rather than heavy, bony jaws, to reduce weight, powerful wing muscles to create thrust in flight, and lightweight, smooth feathers to reduce drag. But birds come in all shapes and sizes, and each species of flying bird has specific adaptations for the type of flight they do most.
Here are four examples of bird wings:
Bald Eagle Wing, Image via Allaboutbirds.org
Laysan Albatross wing, Image via Allaboutbirds.org
American Crow Wing, Image Via ALlAboutBirds.org
White-Throated Swift, Image via AllaboutBirds.org
What differences do you notice? How are the wings shaped? What do the feathers look like? Have you seen any of these birds flying before—what did that look like?
Let’s start by looking at the bald eagle’s wing. Eagles have wide, broad wings, called passive soaring wings. The wide shape and the slots (where the feathers stick out on the side) allow the bird to catch a lot of air in their wings. Birds with passive soaring wings, like eagles, vultures, and storks, catch vertical columns of hot air to fly and glide really high up, due to the drag of the feathers.
The albatross’s wing looks very different from the eagle’s. While the eagle’s wing is wide with feathers sticking out, the albatross’s is thin and smooth. This wing shape, called active soaring wings, allows the bird to minimize drag, speedily cutting through the air. Birds with these wings are often found at sea—albatrosses, gulls, and gannets all have active soaring wings—because with a steady ocean breeze, these birds can glide above the water for days at a time. There is a drawback to these wings, though. Active soaring wings are very good for staying in the sky, but because they move so smoothly through the air, it takes a little more work to get into the sky.
Now the crow’s wings and the swift’s wings are somewhere in between passive and active soaring wings. A crow has wide, slotted wings, but they aren’t quite as broad or have as many feathers sticking out as an eagle’s; a swift has long, smooth wings, but not at the same level as an albatross’. Since these wings are in the middle of the spectrum of wing types, it means that they share some qualities of the other types of wings.
A crow has elliptical wings. Because elliptical wings are broad—but not too broad—it allows birds with these wings quickly take off, but that speed can’t be maintained due to the drag of the feathers. Birds with this type of wing are what you would see in your backyard—crows, ravens, jays, sparrows, and thrushes (like the American robin). A swift has high-speed wings, which, as the name implies, allows a bird to fly very fast and maintain that speed for a long distance. Like active soaring wings, because high-speed wings are so thin and smooth, they allow the bird to fly without much air resistance. Birds with these wings include swifts, falcons, terns, and ducks.
So this week, we’ve seen applications of the principles of flight in human-made machines, like planes, hot air balloons, and parachutes, and here we see one application of aerodynamics in the natural world.
Now, let’s take a closer look at one type of bird wing of your choice by making a flapping bird puppet.
Flapping Bird Puppet
Materials:
Cardboard
Pencil
Scissors
Paint
Hot glue gun*
Craft knife*
Tack, or other sharp object*
String
Sewing needle*
Cardstock
Tape
*Make sure you have adult supervision while using sharp and hot tools!
Instructions:
1. Pick your favorite bird and draw its body, wings, and tail on the cardboard, cutting a slot into the tail and body to connect these later. In these instructions, we’re making a seagull puppet. Cut out the shapes and paint them to look like your bird.
2. Cut out a cardboard rectangle that’s about 2.5 inches by 10 inches, roll it into a cylinder, and glue together. Using the craft knife (and adult assistance, if necessary), cut out a notch on one end of the cardboard cylinder. This will be the puppet’s stick.
3. Glue the tail and body together. Glue the body into the notch of the stick.
4. Cut out four small cardboard rectangles, each about 0.5 inches by 2 inches. Fold the rectangles in half and glue one half of two rectangles to each wing. Glue the other halves of the rectangle to the body, forming hinges for the wings. Paint the hinges to match the body and the bottom of the wings.
5. Using the tack, punch three holes in each wing: one at the end of the wing and two next to each other in the middle of the wing.
6. Cut two lengths of string, each about 15 inches long. Tie a knot at one end of each string and thread through the holes in the wings as shown below. Once the strings are below the body, tie knots at the end of each string.
Start by threading the string through the hole on the end of the wing with the knot on the bottom…
…Then go through the first middle hole from top to bottom, the second hole from bottom to top…
…Place the ends in the space between the wings and the body. Be sure the string is next to the opposite side of the body that the wing is on.
7. Cut out a rectangle (about 4 inches by 5 inches) from the cardstock paper. Wrap the paper around the puppet stick. Pull the strings tightly and glue to the inside of the paper, and tape down the strings above the glue to secure. Glue the paper together to form a tube around the stick. This forms the mechanism to flap your puppet’s wings.
Your puppet is done—pull down on the paper tube and watch your bird fly!
Think about how your puppet’s wings reflect an actual bird’s wings. If you made a puppet with passive soaring or elliptical wings, what do you notice when you flap the wings? What about a puppet with active soaring or high-speed wings?
