regular air

materials


- Two-hole rubber stopper; one hole slightly larger that the other to allow for the lighter to fit through (height: 2.5 cm, diameter at base: 3.5 cm, diameter at top: 4.25 cm)
- Lighter sealed with silicone to prevent air passing through the tube
- Silicone
- 3/16” inner diameter, 5/16” outer diameter clear flexible tubing (“tubing size #2”)
- Pressure sensor attached to computer
- Limewater (20 ml for each test)
- T (for separating tube)
- Glass container that stopper fits snugly without leaking (height: 13 cm, diameter at base: 6.5 cm, diameter at opening: 4 cm)

 

method
setup:

1. unscrew lighter and seal tube by injecting generously with silicone
2. reassemble lighter and let dry (about twenty-four hours)
3. test lighter to be sure it is airtight
4. fit lighter tube into large hole of rubber stopper and make sure it fits tightly so no air can leak through
5. in the other hole of the stopper, fit the size #2 tubing, making sure it fits snugly
6. fit one end of T onto one end of size #2 tubing (the end not in the stopper) make sure this is snug and will not leak
7. take two more lengths of size #2 tubing and fit onto T, again checking for leaks
8. onto one branch, fit pressure sensor; make sure this is airtight and does not leak

experiment:

1. pour limewater into glass container
2. quickly insert stopper into container
3. start computer
4. light lighter and count one second (“one-mississippi”)
5. quickly plug end of tubing that was left uncovered (we used our fingers)
6. wait for lighter to extinguish
7. once it goes out, stop computer
8. pour limewater out and repeat experiment again for more trials

diagram:

 

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nitrox

materials


-Two-hole rubber stopper; one hole slightly larger that the other to allow for the lighter to fit through
-Lighter sealed with silicone to prevent air passing through the tube
-1/4” inner diameter clear flexible tubing (“tubing size #1”)
-3/16” inner diameter, 5/16” outer diameter clear flexible tubing (“tubing size #2”)
-Airtight valve that size #2 tubing fits into without leaking
-Pressure sensor attached to computer
-Limewater (20 ml for each test)
-T
-Glass container that stopper fits snugly without leaking (height: 13 cm, diameter at base: 6.5 cm, diameter at opening: 4 cm)
-Airtight valve that tubing size #2 fits snugly into without leaking
-Balloon filled with Nitrox
-About 2-3” of 1/4” copper tubing
-Wire
-Vacuum pump (ours used kpa and would pumped to 30 kpa. This is subtracted from 100 kpa, or 1 atmosphere of pressure, which means that the pump can only vacuum 70 kpa of air out. Therefore, there is still some regular air remaining in the container.)method

method

setup:

note: test the regular air before testing the Nitrox



1. on one branch of the size #2 tubing, attach the airtight valve
2. on the other branch, leave the pressure sensor
3. attach the other end of the valve to another length of size #2 tubing
4. put the other end of the tubing over the end of the copper tubing
5. take a piece of wire and twist it tightly over the part of the plastic tubing covering the copper tubing so that it forms a seal that does not leak
6. take a length of the size #1 tubing and put it over the other end of the copper tubing
7. twist wire over the part of the size #1 plastic tubing covering the copper tubing the same way as before
8. attach the other end of the size #1 tubing to the vacuum pump

the experiment:

1. pour limewater into glass container
2. quickly insert stopper into container
3. pinch the branch of the size #1 tubing attached to the pressure sensor so that it closes (this keeps the pressure sensor from breaking when the air is vacuumed from the container)
4. make sure valve is open
5. pump as much air out of the container as possible (we were able to pump about until the gauge on the vacuum read 20 or 25 kpa)
6. close valve
7. remove vacuum
8. attach balloon filled with Nitrox to tube where vacuum was attached
9. open valve
10. wait until it seems like the Nitrox has filled the container and the pressure is about normal
11. let go of seal on pressure sensor
12. start computer
13. light lighter and count one second (“one-mississippi”)
14. quickly plug end of tubing that is inside balloon (we used our fingers)- leave balloon on
15. wait for lighter to extinguish
16. once it goes out, stop computer
17. pour lime water out and repeat steps 1-16

diagram:

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