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smile1's avatar

Help with a physics competition? Blowing in the wind?

Asked by smile1 (493points) May 24th, 2010

For physics, we have a competition, as stated below, and I’ve tried so many different designs but none seem to work!! If you guys have any ideas I would love to hear them! Thanks!!
A. Objective

The objective in this event is take the air current created by a hair dryer and to design and build a device that harnesses this air current in order to lift a mass the greatest height. The hair dryer will lay on the floor and shoot the air horizontally.

B. The Apparatus

1. Teams will be given one supply of the following: 5 plastic cups, 4 paper plates, some straws, 3 pipe cleaners, two sandwich bags, 1 meter of duct tape, 1 meter of string, 3 sheets of paper, one folder, 2 note cards, and are allowed to use the physics mass sets.

2. The above supplies are the only supplies a team will get, and they are allowed to use as much or as little of these as the wish.

3. The device may be a large or small as the team desires.

4. Team may test their device as many times as they wish.

5. Nothing is allowed to touch the hair dryer.

6. No other materials besides the ones given may be used. (only one set per team!)

7. The apparatus must stay in the classroom at all times.

8. No counterbalance systems of any kind are allowed. Please check with a judge if your need clarification.

C. The competition

1. Teams will be given 2 minutes to compete in this event. The time begins once the hair dryer is turned on.

2. Teams may choose to lift any amount of mass they wish up to 200 grams total.

3. Stopping and starting the hair dryer is permitted during the two minutes.

4. The device may touch the ground during the two minutes.

5. The height reached will be measured from the bottom of the mass and will be done so by the judge.

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18 Answers

chyna's avatar

The answer my friend is blowing in the wind.

smile1's avatar

haha. :) seriously though…any ideas?

lilikoi's avatar

“lift” – is it acceptable to shoot it in the air like a projectile?

FireMadeFlesh's avatar

The easiest way is to tear the smallest piece of paper you can off one corner. It will rise a good distance before it is blown out of the updraught.

Edit: Given the information below, this is obviously not possible. The best way would then to construct a lever powered by a sail to catch the wind from the hair dryer.

lilikoi's avatar

So there is no minimum mass? That seems odd…

smile1's avatar

we have to use the weights provided. the minimum weight is 10 grams!

lilikoi's avatar

I’d probably start by using the cups to make a ‘duct’ that redirects the air from horizontal to vertical. The sandwich bags could be adhered to the cups to create an ‘elbow’ in the duct. Make some kind of piston action…

Wait. Maybe I’d duct tape the sandwich bag around the dryer and tape a straw vertically penetrating the bag so that the warm air shoots into the bag, then is forced out the top through a small hole.

smile1's avatar

yes, it is legalto shoot it in the air like a projectile, as long as nothing is touching the hair dryer. the hair dryer has to stay blowing horizontally though.

lilikoi's avatar

So you can’t tape anything to the hair dryer?

smile1's avatar

but I can tape things on the floor…AROUND the hairdryer. as long as its not touching the dryer.

stranger_in_a_strange_land's avatar

I can think of two concepts: If you’re allowed to use the heat from thr dryer, build some kind of paper and plastic hot air balloon. If you have to use airflow only, build the most efficient airfoil you can; use the string to tether it like a kite so it won’t be blown backwards (I doubt you’ll get more than a meter of lift anyway).

smile1's avatar

@stranger_in_a_strange_land how do you think i should make an airfoil that can lift straight off from a horizontal flow of air? just a square piece of paper and, string holding the corners, coming together to hold the weight?

stranger_in_a_strange_land's avatar

Like a kite. Use the papers, folder, paper plates and bags for the lifting surface; straws for strut bracing; string taped to the floor as a tether. Pipe cleaners or string to attach the mass. You could also use the folder to make girders by cutting strips lengthwise and folding to a triangular cross-section. A kind of wing-shaped kite. Use the cups to make a tube that you can use to redirect the airflow upward once the “kite” starts to rise.

lilikoi's avatar

Here you go

Let me know if it works :)

lilikoi's avatar

You know it doesn’t say you can’t use materials other than what is supplied….

zenele's avatar

@lilikoi That was funny.

rebbel's avatar

A little related (wind, plastic, energy), i thought to share this with you.

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