something about physics experiment?

Question

Clean a penny and a dime by brushing them with toothpaste and rinsing them carefully.
2. place the dime on top of your tongue and then hold the penny under you tongue.
3,move them forward until the edges of the coins touch, with your tongue in between
4. Now rinse your mouth with strong salt water, a teaspoonful of salt to a glass of water.
5.Repeat the procedure as in Step 2.

Results
1. What happened when the coins touched the first time?
2. What happened when the coins touched the second time?

please explain this experment to me, I have some problems to under it.

Answer 1

The two different metals will act as a battery and generate electricity.

The salt water will increase the conductivity and create more electricity, so you will feel more of a spark. See "Homemade" under the site below.

Answer 2

When two different metals come into contact, there is a potential difference that causes a current. In other words, it's just like putting a 9-volt battery on your tongue... just not as powerful. The salt causes an increase in electrolytes in your mouth which increases the current. If you want to find out more, you can try searching for contact potential on the internet. I tried looking a few days ago, but only found one thing and you might not be able to understand what it is talking about. I would suggest you ask your teacher, assuming you are taking a physics or chemistry class, to explain it to you.