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2. Sodium hydroxide corrodes metals of Cola cans and paper but no plastic

Photo 1: The yellow lable warns against corrosive liquids: They "eat up" stones, metals, clothes, skin.
Photo 2: This hole was corroded into a sweatshirt by the sulfuric acid of a car battery.

Experiment:
1. Test the corrosive effect of sulfuric acid from a car battery on your tray and on a piece of tissue paper.
2. Treat marble, a piece of egg shell and the limestone on a wash basin with less dangerous acids.
3. Home experiment: Remove the shell of an egg by corrosive vinegar 20%.
What you need:
Tray, tissue paper, drops of sulfuric acid from a car battery, empty blisters,  (Tabletten-Durchdrück-Verpackungen), magnifying glass, dropper bottle with vinegar (10%), piece of marble.
Experiment:
1. Put one drop of sulfuric acid DIRECTLY from a car battery to the middle of your tray.
    Test the corroding effect of the acid on the the tray after 5 minutes. Cover the drop with a 5 x 5 cm piece of tissue paper.
2. Photo 3: Put a Cent coin into your tray. Add a small piece marble, cover it by drops of vinegar. (Marble may be replaced by egg shell).
Write down your observations:
Is the tray corroded by battery acid? What happens with the tissue paper?
Photos middle and right: Describe what happens to marble and coin.