Science Buddies: "Ask an Expert"

My third grader wants to do "Paper Airplane Project". He will create few designs and see which goes farther. How can we increase the scope of this? Any other calculations that he can do?

nissan,

Thank you for your question. This project, or ones like it tend to be quite popular. To help in research and refining your project I have included one from the SB project ideas, here:

https://www.sciencebuddies.org/science- ... eityourown

The thing to remember is that a good Science project has one independent variable that is changed at a time with dependant variables that will be measured. Your 3rd grader should decide what aspect of the planes design they will change, such as wing size or weight or drag and try to hold all other variables constant. Distance flown can be a good metric, but some rigorous attention to control variables should be paid. More discussion on variables can be found in the SB project guide.

Thank you so much for the reply. You said its very popular, are there other posts that I can refer who asked this question? I searched for paper airplanes in the forum but could not find any. May be my search criteria should be different. Can you help me.

nissan,

First let me say sorry and clarify my comment. By popular, I meant at science fairs in general. For every one I have judged, there is always at least one paper airplane project (usually more). That being said, there are posts related here on the forum. I've provided 2 here for your consideration.

https://www.sciencebuddies.org/science- ... hp?t=12793

https://www.sciencebuddies.org/science- ... hp?t=12771

Not sure which way you are going to go, but remember to pick just one variable to test/change and measure response to that change.

For example, adding weight to identical plane design and seeing any difference in distance flown. Or changing drag and measuring the flight difference.

Please post back with any other questions.

We did the experiment, whenever we added some weights(paper clips) to the front of the paper airplane, the plane flew farther, no matter what the design is.
How can we explain this? Help please?

Sorry for the delay in replying. Without knowing your designs, this is just a guess, but I would say that it has to do with the parameters known as center of gravity (COG) and center of pressure (COP). In aerodynamic terms, the thrust, generated by your hand when you throw the plane acts through the COG. Drag, generated by friction with the air as the plane flies through the air, acts through the COP. Smooth, stable flight occurs when the COG is close to the nose as when there is more weight there from the paperclips And when the COP is towards the back as when there is large wings with large surface area in the back. The further the COG and COP are from each other the more stable the flight which usually translates into longer flights. vice versa, the closer these points are or if they are reversed, so that COG is towards the back and COP towards the front, this is an unstable configuration and likely going to crash after a very short flight.

let me know if this matches with your observations.

Another explanation....

If you throw a rock, it travels pretty far.
If you throw a feather (or a piece of paper) it does not go very far.

This is because the air does not resist the rock's motion very much (it is heavy compared to the area pushing against the air), where paper or feather is light with a large surface the air can interact with.

The distance difference you are seeing might be as simple as that. Putting a weight on the nose of your paper airplane increases its mass compared to its surface area, and it will behave more like a rock than a feather. A well designed paper airplane might travel further than a rock, a poorly designed one of the same weight would travel about as far as a rock, or a bit less (air resistance from shape overwhelming any lift from the wings).

Most paper airplanes are designed more for how long they stay in the air than any attempt to get distance - or alternately to "catch a breeze" or wind to carry them much farther than you can throw a rock. So if you are using the design somewhere with no wind (like a gym or other large inside room) you might be doing the airplane a disservice.

There are some designs focused on flying straight and going a fair distance. They'll outstrip anything else of their same weight. But it's unfair to compare them to an aircraft with the same shape but a nice heavy front surface...the mass compared to the drag matters a lot in how much force you can put into the throw without damaging the paper airplane. (put that weight somewhere other than the front or wherever you grip with your fingers and it'll be a lot less helpful)

(I'm really saying about the same thing as the prior poster, but expressing it in less technical terms)

where can we find out facts on the distances for paper airplanes it is very hard to find and do research for this project

Hi erikae,

I'm sorry to hear that you are having difficulty doing the research for the paper airplane project you are working on/helping with. This article from Scholastic does a nice job of explaining the physics behind paper airplanes in simple, K-5 appropriate terms.

http://www.scholastic.com/teachers/arti ... planes-fly

Do you have other, specific questions about paper airplanes? The more specific your question, the easier it is for us to help you effectively.