How can the density of air be measured using simple equipment?

Click For Summary
SUMMARY

The density of air can be measured using simple equipment, specifically a scale with 0.01g accuracy, two empty glass bottles (approximately 0.33 liters each), a large bowl of water, a cork with a valve, and a vacuum pump. The process involves measuring the volume of water that fills the bottles to determine their volume, then weighing the bottles with and without air to calculate the mass of the air. Using the formula for density (ρ=m/V), a rough estimate of air density can be achieved, confirming that the method is valid and effective.

PREREQUISITES
  • Understanding of density calculation using the formula ρ=m/V
  • Familiarity with the Ideal Gas Law (pV=nRT)
  • Basic knowledge of buoyant force (F=ρgV)
  • Experience with measuring equipment, specifically scales and volumetric measurements
NEXT STEPS
  • Research methods for accurately measuring small masses using precision scales
  • Learn about the Ideal Gas Law and its applications in real-world scenarios
  • Explore buoyancy principles and their relevance in fluid mechanics
  • Investigate alternative methods for measuring gas density using different equipment
USEFUL FOR

Students in physics or chemistry, educators teaching gas laws, and hobbyists interested in experimental science will benefit from this discussion.

Alettix
Messages
177
Reaction score
11

Homework Statement


Measure the density if air at normal atmospheric pressure. You can use the following equipment:

One scale with an accuracy of 0.01g
Two empty glas bottles (≈0,33 liter each)
One big bowl with water
One cork with a valve and a vacuumpump

Homework Equations


Not knowing how to solve this problem I am not sure which equations should be used, but the following could be relevant:
Density: ρ=m/V (1)
Ideal Gas equation: pV=nRT =NkT (2)
Buoyant Force: F=ρgV (3)

The Attempt at a Solution


My first thought was that the exact volume of the bottles can be measured by measuring the weight of the water which fit into them and then by knowing the density of water the volume is obtained. Then, we can meausre the weight of an empty bottel with air in it and without. From this, the mass of the air inside the bottles is obtained and the density of the air is achieved. However, I feel like this is a bit to simple. I don't have the equipment to try this at home. Do you think think this solutions works? Or do you have other ideas?

Thank you for your help! :)
 
Physics news on Phys.org
Why do you think it is too simple?
 
  • Like
Likes   Reactions: Alettix
Orodruin said:
Why do you think it is too simple?
I thought the mass of the air was too small to be measured, but now I realized that m = 1,293*0,00033 ≈0,43 g.
So maybe this is the solution?
 
Yes, it should be enough to at least give you a quite rough estimate.
 
Orodruin said:
Yes, it should be enough to at least give you a quite rough estimate.

Well, in that case the problem is solved. Thank you very much! :)
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
18
Views
7K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 1 ·
Replies
1
Views
25K
Replies
11
Views
2K
Replies
2
Views
2K
Replies
6
Views
3K
  • · Replies 5 ·
Replies
5
Views
7K
  • · Replies 1 ·
Replies
1
Views
2K