Maximize Weight Lifted with Hair Dryer Machine | Homework Help

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Discussion Overview

The discussion revolves around a homework project where students must design and build a machine that lifts the maximum weight using only a hair dryer as the power source. The project includes specific rules regarding the weight to be lifted, materials allowed, and constraints on power sources.

Discussion Character

  • Homework-related
  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests creating a turbine that utilizes the hair dryer's airflow to lift weights, potentially using pulleys for mechanical advantage.
  • Another proposes heating a fluid in a sealed system, such as a bag of air or a water-filled cylinder, to create lift.
  • A participant questions whether the hair dryer can heat a fluid sufficiently to produce usable energy, expressing concern about the complexity of ideas presented.
  • One reply discusses Boyle's law and how heating air in a sealed bag could cause it to expand and lift a weight, providing a rough calculation of potential height increase.
  • Another participant raises questions about the clarity of the rules, suggesting the possibility of using a hydraulic system or pressurized piston, while also considering the legality of such designs within the project constraints.
  • One participant calculates that if the hair dryer can produce a pressure of 5 inches of water, it could theoretically lift over 130 kg using a sealed system of plywood.
  • Concerns are raised about measuring the hair dryer's pressure output, with requests for visual aids to better understand the concepts discussed.
  • A participant expresses uncertainty about the feasibility of building a piston-based design, despite it being recommended by others.

Areas of Agreement / Disagreement

Participants express a variety of ideas and approaches, with no consensus on a single method for achieving the project goals. Some ideas are met with skepticism regarding their complexity or feasibility, indicating ongoing debate and exploration of different models.

Contextual Notes

Participants note limitations in understanding the physics involved and the practical challenges of building proposed designs. There are also unresolved questions about the interpretation of project rules and the legality of certain mechanisms.

Who May Find This Useful

Students working on similar engineering or physics projects, educators looking for examples of student discussions on practical applications of physics concepts, and individuals interested in creative problem-solving using limited resources.

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Homework Statement


Basically, using only a hair dryer as the source of energy, students need to create a machine that will lift a maximum amount of weight. Students get graded according to who can lift the heaviest weight. The record seems to be around 40kg...

Homework Equations


Can anyone inspire me a few ideas on how to achieve this??

The Attempt at a Solution


All I can think of is creating some sort of 'turbine' that would catch the hairdryer's air and rotate the turbine to lift the weight (creating mechanical advantage using pulleys or something like that)...

====

EDIT - here are the complete rules:
the "Heavy-Weight Lifting Machine" - design&build a machine that lifts as much weight as possible up to a height of 110cm in any given time (meaning it could take a year to lift). The machine has to lift a min. of 260 grams. But the grade depends on the rank of the heaviness of the weights lifted. For example, if I lift 300g, and some other guy lifts 40kg, I will get a lower grade than he does... pretty simple. :(

Additional Rules:
1. The hairdryer can be the only source of power. It can be the ONLY TYPE of power that supplies the power - so I CANT batteries using the hairdryer... I also can't use the motor inside the hairdryer directly - like taking it out and doing something with it.
2. No counter weights - I can't drop a heavier weight to lift another object
3. ANY materials can be used to build the machine (metal, paper, foam, string, wire, etc), - BUT the total cost of the machine CANT exceed $25. BUT the items being used CAN be those that are recycled. For example, if I happen to have a "combustion engine" lying in my backyard, I could use it... Only I don't have a combustion engine lying in my backyard.
4. The machine can be set on a chair, floor, desk - anywhere.
5. The hairdryer can be moved around using my hands...

THOSE are the ONLY rules there were given. No more, no less!
 
Last edited:
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I'd look at heating a fluid in a sealed system, possibly a bag of air with the weight on top then heat the bag, or a water filled cylinder with piston. For smaller weights but a better "wow" factor how about a hot air balloon?
 
Could a hairdryer heat the fluid hot enough to produce any kind of energy?
I don't quite get what you are saying :(

This is a high school project - I am hoping the ideas are not too complex for me :(

Thank you anyways..!
 
You don't say how far you are required to lift the weight, but the air in a sealed bag will expand as it is heated up. Remember your Boyles law P1*V1/T1 = P2*V2/T2 assuming that P will remain constant and that all the bag expansion will be upwards (V2>V1) If you start with the air in the bag at 20 Deg C and can increase the temperature by 10 Deg C the the upward expansion will be 3% of the original height.
 
My bad!
Here are the requirements:
1. Lift up a mass of AT LEAST 260g
2. The machine must be able to lift at least a 110cm from the ground...

Sorry about that..!
 
The rules aren't clear enough... can you run the wire through the hairdryer, bypass the heater coil, go through another circuit then to a hydraulic fork lift? Is there a limitation to the additional items you can use to support your hairdryer? Blow someone's hair (for dramatic effect) as he lifts up the object? What's the shape of the object? How high must you lift the object?

OK I had quite a laugh but anyway to be serious... personally I'd look into building a pressurized piston, with the hairdryer somehow inside the chamber. Look into

(1) insulating the chamber from heat loss to the surroundings
(2) minimizing the height of the pressurized air column which is to be heated
(3) using a gas with high mol-to-volume ratio
(4) designing the piston (how is it going to be sealed air-tight, how are you going to pre-pressurize the air inside and seal it before running the hair dryer - weld on a valve?)

But clarifying the rules will help - I'm not sure - is a piston legal within the rules? How about chemicals? Is it fair to pressurize the piston before you start to use the hair dryer? I mean, if resources aren't a limit you could design something like a combustion engine and just have the hairdryer to somehow trigger an explosion, which is very possible, too.
 
I don't quite get the piston idea - could someone give me a visual aid? :(
==
Sorry... I might as well type up the whole paper.

the "Heavy-Weight Lifting Machine" - design&build a machine that lifts as much weight as possible up to a height of 110cm in any given time (meaning it could take a year to lift). The machine has to lift a min. of 260 grams. But the grade depends on the rank of the heaviness of the weights lifted. For example, if I lift 300g, and some other guy lifts 40kg, I will get a lower grade than he does... pretty simple. :(

Additional Rules:
1. The hairdryer can be the only source of power. It can be the ONLY TYPE of power that supplies the power - so I CANT batteries using the hairdryer... I also can't use the motor inside the hairdryer directly - like taking it out and doing something with it.
2. No counter weights - I can't drop a heavier weight to lift another object
3. ANY materials can be used to build the machine (metal, paper, foam, string, wire, etc), - BUT the total cost of the machine CANT exceed $25. BUT the items being used CAN be those that are recycled. For example, if I happen to have a "combustion engine" lying in my backyard, I could use it... Only I don't have a combustion engine lying in my backyard.
4. The machine can be set on a chair, floor, desk - anywhere.
5. The hairdryer can be moved around using my hands...

THOSE are the ONLY rules there were given. No more, no less!
=====
 
Last edited:
I've been doing some sums on this, if the hairdryer can produce a pressure of 5" water, (this is probably quite conservative) then if you can constrain this under an area of 1 square meter you should be able to lift over 130 Kg. I'd get two pieces of plywood and connect them with airtight (well fairly) material (salvaged carrier bags might do) connect the hairdryer up and blow air inbetween the two pieces of wood. This sounds like a job that will call for lots of duct tape!
 
Wait - my knowledge in physics is very limited... (The teacher is honestly asking for too much.. I think... )

How would you measure if the "hairdryer can produce a pressure of 5" water?"
Could someone provide me with some sort of visual aid so that I can better understand this? Sorry :(

Thank you...
 
  • #10
To test the pressure capability of the hairdryer you will need a large plastic bag (rubbish sack) some clear plastic tube, a ruler and duct tape.
Tape the bag to the hairdryer so that the dryer will inflate the bag.
Fashion the tube into a U tube manometer (http://en.wikipedia.org/wiki/File:Manometer_(schematic_U-tube).svg) poke one end of the tube into the bag and tape in position, put enough water into the tube to come about halfway up each leg.
Make a small hole (about a pencil size) in another part of the bag.
Run the hairdryer and when the bag is inflated measure the difference in the hieght of the two legs, measurement in inches is the pressure that the hairdryer produces.
 
  • #11
Jobrag, thank you so much for the replies you've been giving.
I talked to a physics major friend of mine for literally a couple minutes, and he also thought the piston/chamber idea would be the best way to lift a heavy weight.
But he also said that it would be extremely hard to build such a machine. Plus, as of now, I really have no clue as to how I will build the actual machine...

Could you give any advice on this as well? thanks..!
 
  • #12
Did you test the pressure capability of the hairdryer?
 

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