This is an excellent project to show how *impurities conduct electricity*.

 

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 # 💡 *DIY Water Purity Indicator – Step-by-Step*

 

 ## 🎯 *Aim*

 

 To show how clean water and impure water conduct electricity differently.

 

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 # ✅ *1. Materials Needed*

 

 

 1 LED (any color)*

 

 9V battery or 3V coin cell

 

 2 metal wires/nails (stainless steel or copper)

 

 Small plastic cup or container*

 

 Electrical tape* Breadboard (optional)

 

 Salt, sugar, tap water, muddy water (for testing)

 

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 # 🛠 *2. Preparing the Sensor Probes*

 

 

 1. Take *two metal wires or nails*

 

 2. Fix them to a small piece of cardboard or plastic so they are:

 

  * *Parallel*

  * *1 cm apart*

 

 3. Do NOT let them touch each other.

 4. These two wires act as *water sensors*.---

 

 # 🔌 *3. Wiring the Circuit (Very Simple)*

 

  1. Connect the *positive wire* of the LED to the *positive (+) terminal of the battery*

 

  2. Connect the *negative wire of the LED* to *Probe 1*

 

  3. Connect *Probe 2* to the *negative (–) terminal of the battery*.

 

  ✔ When the probes touch water, current flows → *LED glows*

  ✔ Higher impurities → stronger glow

  ✔ Cleaner water → dim or no glow

 

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 # 🧪 *4. Testing the Water Quality*

 

 ### *Test 1: Pure Distilled Water*

 

   * LED will NOT glow or glows VERY dim.

   * Because pure water is a poor conductor.

 

 ### *Test 2: Tap Water*

 

   * LED glows slightly.

   * Tap water has minerals and salts.

 

 ### *Test 3: Salt Water*

 

   * LED glows very bright.

   * Salt makes water conduct electricity strongly.

 

 ### *Test 4: Muddy Water*

 

   * LED glows depending on particles.

   * More impurities → more conduction.

 

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 # 🧠 *5. How It Works (Simple Explanation)*

 

   * Electricity needs *ions* (charged particles) to flow through water.*

   *Pure water has almost no ions*, so electricity cannot pass → LED stays OFF.*

   *Impure water contains ions* like:

 

   * salt (sodium, chloride)

   * minerals

   * dirt

 

     So electricity passes → LED glows.

 

 The *brightness* of the LED shows *how impure the water is*.

 

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 # ⚠️ Safety Notes

 

        -Do not use high voltage.

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        -Do not let the LED wires touch water.

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        -Do not taste any water used in tests.