The Lift Force of Butterfly’s Gliding

When researching the migration of butterflies, the teacher Jenher Jeng accidentally found a website by a web smart search robot he(Jenher Jeng) invented, named Lufton. The website introduced the gliding of butterflies, how to build a simple wind tunnel, that is a flight simulation, and did a project on a wind tunnel.

S.01 Defining a Problem

How can change the angle of a butterfly wing relative to the wind, and which angle saves the butterfly the most energy?

S.02.5 Hypothesis

They use about 45 degrees when they glide because it uses less energy.

S.03 Realizing the Situation

When I finished reading the website, I found the materials were not very hard to find, and I needed to see which angle had the smallest amount of the lift.

How do the butterflies glide:

There are four forces the butterfly has when it is gliding:

• The weight is the force that puts the butterfly down to the ground, for example, the gravity of the earth and the butterfly’s body weight.

• The lift is the force that pushes up the butterfly and allows it to go upward to stay in the air and have to overcome the weight.

• The drag is the force that pulls back the butterfly and slows it down while flying.

• The thrust is the force that allows the butterfly to go forward and go faster, and a butterfly generates it.

Figure 1. How do the four forces work

What is a wind tunnel:

People used wind tunnels to do scientific experiments. There are many kinds of wind tunnels, but we will use the wind tunnel shown in “Figure 2.”

Figure 2. We put the simulated butterfly wing into the test section, which makes the air go faster because of the small width of the tube part.

The angel of the attack is the angle between the butterfly’s wings and the direction of the wind. One thing the scientists tested was how the angle of attack affects the lift of the butterfly.

Figure 3. This picture shows the angles of the attack of 0 degrees, 45 degrees, and 90 degrees. Wind direction is the force of the drag.

S.04 Stratifying the Factors

The things I need to include to build a simple wind tunnel and the paper butterflies that I use to replace the real butterfly:

1. A fan for blowing the wind.

2. Wooden craft sticks to make the butterflies stay still.

3. A hot melt adhesive for attaching the wooden craft sticks.

4. Scissors for cutting some of the wooden craft sticks in half.

5. A protractor for getting the angles right.

6. Two small binder clips for attaching the paper butterfly and the wooden craft sticks.

7. A kitchen scale for measuring the lift.

8. Several heavy objects for making the wooden craft sticks stay still, such as light batteries and heavy tapes.

Figure 4. The equipment needed in this science experiment was put on the plate.

S.05 Collecting the Data

I test the angles from 0 degrees to 90 degrees. I write down the reading from the scale every 5 seconds and get the average.

Figure 5. A table of the record of the butterfly gliding science experiment.

Figure 6. The representative pictures of the Lift Force of Butterfly’s Gliding science experiment.

S.07 Analyzing the Data

I found out that when the butterfly uses 30 degrees to 40 degrees to glide, it will save the most energy. When the butterfly uses 80 degrees to 90 degrees, it will save the least energy.

Figure 7. The line chart of each angle of attack with the corresponded force of lift.

S.08 Refining the Problem

1. If I use different wind speeds, will 30 degrees to 40 degrees still save the most energy?

2. I only use one pair of wings to measure. What if I use two separate teams of attachment? Will the measurement still be the same?

3. I had to use a fan for this science experiment. What if I use the air conditioner or use more fans the next time?

4. What if I change the surface area of the butterfly and its wings? Will the measurement be different?

5. I will use more advanced tools for the wind tunnel. For example, I’ll use an actual 3D printed wind tunnel and natural-sized butterflies next time I do this experiment.

6. I will use more advanced tools like “Arduino Uno” and “Micro: bit” the next time I do this experiment.

Reference:

https://www.sciencebuddies.org/science-fair-projects/project-ideas/Aero_p049/aerodynamics-hydrodynamics/butterfly-wings-using-nature-to-learn-about-flight?id=860