Why is my salt solution not lighting the bulb?

In summary, the person is attempting to demonstrate the conductivity of saltwater by using a 9volt battery and a Christmas light. However, the bulb does not light up when the wires are connected in the solution, despite showing some conductivity with a conductivity tester. The wires also show signs of hydrolysis and electroplating, possibly due to a coating or ion identity. The person suspects that the current may be too low and suggests increasing the electrode surface and adjusting the salt to water ratio.
  • #1
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So I have a typical 9volt battery attached to a Christmas light and am attempting to demonstrate the typical "saltwater can conduct electricity" gimmick by showing that the bulb lights when completing the circuit in the solution. I'm racking my brain though and can't figure out why the bulb won't light!

Some details:
-The bulb does of course light when the wires are connected outside of solution.
-I've tried multiple solutions with multiple concentrations (calcium chloride, acids, NaCl, etc) with no luck.
-However, a conductivity tester also attached to a 9volt battery does show some conductivity in the water.
-The test battery with the Christmas light does hydrolyze the water (produce bubbles).
-After attempting the test setup in the solution, I stuck the wires together for a bit outside of the solution. When I did this, one of the wires began to blacken just a tiny little bit. I then stuck the wires back in the solution and a slight yellow precipitate formed. This makes me think there is some coating on the wire (though I don't see why there would be) or that there is some electroplating going on (though this is never really noted in other setups of this experiment I found on the internet). The yellow precipitate I noticed in the NaCl solution.
-The Christmas lights was just the typical LED green chains you normally see. One of the lights was taken off just by cutting the wires on both ends of a light. Simple simple.

Any ideas as to what's going on?
 
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  • #2
Have you measured what is the current flowing through the circuit? My bet is that it is just too low for the light.
 
  • #3
That may well be it. The light is NOT an LED like I originally posted on second thought (or at least that's not a safe presumption; I don't know how to truly tell the difference visually). But no I didn't measure the current numerically.

Another detail I forgot, the bulb did light up BRIEFLY in an HCL solution. That does make me think the current's somewhat there just not enough for the bulb.
 
  • #4
I just remember that the HCl solution that did work briefly was 3 molar. To get that same concentration in table salt, we would have had to add much more than we did. It seems like there just no being enough juice to get through is a reasonable resolution to this unless anyone seems something missing.
 
  • #5
It is not only about concetration, also about ion identity - H+ are are the best.

Try to increase electrode surface, and try to keep electrodes as close to each other as possible. Conductivity 101.
 
  • #6
also if your doing salt to water your raitio may be off
 
  • #7
just guessing
 

1. Why is my salt solution not lighting the bulb?

There could be several reasons why your salt solution is not lighting the bulb. One possibility is that the concentration of salt in your solution is not high enough to conduct electricity and produce enough energy to light the bulb. Another possibility is that the salt you are using is not a good conductor of electricity. Additionally, the electrodes or wires connecting the solution to the bulb may not be properly connected or may be damaged, preventing the flow of electricity.

2. How can I increase the salt concentration in my solution?

To increase the salt concentration in your solution, you can simply add more salt to the solution and stir until it is fully dissolved. Keep in mind that adding too much salt can also be counterproductive, as it can create a saturated solution that is not conducive to conducting electricity. It is important to find the right balance of salt concentration for the best results.

3. Is table salt the best type of salt to use for this experiment?

Table salt, also known as sodium chloride, is a good conductor of electricity and is commonly used in this type of experiment. However, other salts such as potassium chloride or magnesium chloride can also be used. It is important to use a salt that is easily water-soluble and can form ions in solution for the best results.

4. Can I use tap water instead of distilled water for my salt solution?

Tap water contains minerals and impurities that can affect the conductivity of the solution. Distilled water, on the other hand, is pure and does not contain any impurities that can interfere with the experiment. Therefore, it is recommended to use distilled water for the most accurate results. If you do not have access to distilled water, you can try boiling tap water to remove some of the impurities before using it in your experiment.

5. How can I troubleshoot if my salt solution is still not lighting the bulb?

If your salt solution is not lighting the bulb, you can try adjusting the concentration of salt, ensuring that the electrodes are properly connected, and using distilled water. You can also try using a different type of salt or adding a small amount of vinegar to the solution, as it can increase the conductivity. If none of these methods work, there may be an issue with the bulb or the electricity source, and further troubleshooting may be needed.

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