Step 1: Collecting the Material!!
• 1 cup water
• 2 tablespoons common salt
• 1 tablespoon turmeric
• Metal plate or steel dish
• Paper towel or tissue paper
• 9 v. battery or mobile charger
• Safety pin (optional)
• Plastic pen refill
• Sticky Tape
Once you are ready with the material, you can go ahead!!
Step 2: Mixing Chemicals!!!
It will be a saturated solution.
Now add 1 tablespoon turmeric with 1 tablespoon of salt water.
Mix it to make a paste of turmeric.
Step 3: Preparing Paper!!
Carefully place the tissue paper on the metal plate.
Put and spread a thin layer of turmeric on the tissue paper.
Step 4: Making the Pen
Step 5: Writing!!!!
On the switch of the mobile charger and write using the pen.
The pen writes in red color.
You can also see this project on YouTube on the link below
Step 6: Explanation
This is because of electrolysis of water. Since water is not such a good conductor of electricity so we added salt (an electrolyte).
During electrolysis of salt water, Sodium hydroxide (NaOH) a base is produced. Turmeric, an indicator turns red when come in contact with a base. So when we touch pen with tissue paper, electrolysis happens only in touched area.