STEAM Snack: July
For thousands of years people have wanted to fly. Our legends and fairy tales are full of stories about humans who can fly, gliding through the air.
This month we will be looking at gravity, thrust, lift, and drag while the girls build their own flying machines. The girls will use their powers of observation and problem-solving skills to modify and improve their designs to get the best results.
Why Flying Machines?
An object in flight is constantly in a tog us war between opposing forces, lift vs weight, and thrust vs drag. Humans do not have wings or a power source strong enough to keep us moving through the air to sustain the lift needed for flight. We need help from machines. Planes and birds are both affected by the same forces in flight.
What if I’m not an expert?
This is a simple build to demonstrate how the forces impact an object in flight, there are some great resources in the Volunteer Toolkit for this badge that help you complete the build of the fling flyer. To access the Volunteer Toolkit, visit your council’s website and click on MyGS.
How do I get started?
Materials you need:
- Pen or pencil
- Cardstock (or other heavy paper)
- Paper Clips
- Open space
Take the time to try out the demonstration ahead of time to make sure you don’t have too many surprises when showing the girls.
Here are some discussion questions to get the girls thinking:
- What are some things that fly?
- Birds, airplane, helicopter, bugs, seeds, hot air balloon, ect.
- Do they all fly/glide the same way?
- Brownie: Mechanical Engineering: Fling Flyer – Step 1
All things that fly or glide have to be able to provide enough lift force to oppose the weight force. Gravity is a force that pulls everything toward the Earth’s surface, this pull is called weight force. Lift is a force that acts upwards against weight and is caused by the air moving over and under the wings.
Thrust is the force that moves the object forward. Thrust is provided by:
- Muscles – birds and other flying animals, you with your paper flying machines
- Engines – airplanes
- Wind – kites, hot air balloons
- Gravity – For gliders to actually fly they are diving at a very shallow angle, birds do this to when they glide. Your designs will also take advantage of this too.
The force working against thrust is called drag. This is caused by air resistance and acts in the opposite direction to the motion. The amount of drag depends on the shape of the flying object, the density of the air and the speed of the object. Think about the shape of a jet vs a hot air balloon. Thrust can overcome the force of drag.
If the forces are equal the plane or bird will fly at a constant speed, when the forces are not equal then the object will speed up, slow down, or change direction towards the greatest force.
Flying Machine Two: Helicopters
Materials: Cardstock/, Paper clip, Scissors, ruler, glue
- Cut your paper into a 6 inch by 2 inch rectangle
- At one end, cut about 3 inches up the middle of your paper.
- Make two cuts on either side about ½ an inch higher than your cut.
- Fold the uncut end inward as shown
- Flatten and fold up a small piece of your paper on the end.
- Add a paper clip to hold things in place and add weight so that your helicopter stays upwards while flying.
Fold your cut end in opposite directions to create your helicopter blades.
- Grab them by the paperclip end and throw similar to a paper airplane.
- You will want to find a high place like a balcony or deck to see what they can do.
- You can also simple drop them from your high place and watch.
After each build ask the girls:
- How does this design overcome the weight and drag forces?
- What is creating the thrust? Muscles, engine, gravity?
- What can you do to improve the design?
- Make it go faster?
- Fly longer?
- Fly straighter?
A Plane Snack
Materials Needed: Graham crackers, grapes/blueberries (round fruit for wheels), celery, and peanut butter, toothpicks
- Cut your celery stick to the size that you want your airplane to be.
- Fill your celery stick with peanut butter.
- Using your toothpick attach two grapes to either side of the plane for the wheels.
- Place half of a graham cracker that has been cut lengthwise across the wheels on top of the peanut butter.
- Cut two small very thin celery pieces and attach to the front of your celery stick for propellers.