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Making water split experiment – electrolysis science demonstration.

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Making water split experiment

As we know, water is made of hydrogen and oxygen molecules tightly bound together to form that liquidy goodness we so love to spray on each other. So, if it’s made of oxygen, why can’t we breathe it? We could breathe it IF we could separate the oxygen from the hydrogen. But alas, if we tried to breathe water, our lungs could not absorb the H2O.  If you forget this when swimming, here’s a simple poem to help you remember: The fact is, we cannot lie, if you breathe water, you will die.

Fish use their gills to separate oxygen from hydrogen. For fish, this really is a lot of work. Luckily fish are cold-blooded animals and as such do not require as much oxygen as we do.

Alas, we are people though and as such, are much smarter than fish. We can separate the oxygen from the hydrogen using nothing more than a pencil, wire, and a battery.

  1. Fill a glass ¾ full of a water and salt solution. Don’t use very much salt.
  2. Cut a piece of cardboard and place over the top of the glass.
  3. Take two pencils and sharpen both ends.
  4. Poke the pencils through the cardboard so that they extend down into the water solution. Keep the holes close together – make the holes no more than 1 inch apart.
  5. Attach a wire to the positive terminal of a 9 Volt battery and to the lead of one of the pencils.
  6. Attach another wire to the negative end of the 9 Volt battery. Now touch the other end of the wire to the lead of the other pencil.
  7. Watch the ends of the pencils that are extended into the water. See the bubbles?

The current is passing through the pencil lead and into the water and breaking apart the water molecules into their hydrogen and oxygen components (the salt causes a secondary action and causes the release of chlorine instead of oxygen, but we’ll not get too technical here).

The bubbles forming around one of the pencils are hydrogen and around the other pencil is oxygen (ok, ok, chlorine). And yes, chlorine in larger quantities can be dangerous – if you use too much salt and the solution begins turning green, get the heck out of there quick!

This process is called electrolysis. It’s used in industries too (such as when aluminum is produced) but uses different solutions and much higher currents.

Electrolysis science experiment advance notes

Although we cannot breathe water, “liquid breathing” is possible. Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid (usually a perfluorocarbon) rather than breathing air. It is used for medical treatment and was once considered for use in deep diving and space travel. It is currently done in experimental cases only.

Electrolysis experiment Supplies

Supplies: Pencil, Glass jar, Wire (bare)

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