Formation of bubbles with vinegar and an iron nail.
• An Iron Nail
• Test Tube/Clear Plastic Cup/Clear Glass
Fill the test tube or clear plastic cup or clear glass (be extra careful if using a glass container) up to around 5cm with vinegar (this works best with clear vinegar, i.e. white vinegar or distilled malt vinegar).
2. Sand down the tip of an iron nail using sand paper.
3. Place the nail in the vinegar. Adult supervision is required here.
4. After a few minutes you will be able to see bubbles forming on the nail and rising through the vinegar.
The bubbles are of hydrogen. When iron reacts with vinegar, the metal rusts and causes an exothermic chemical reaction, which produces heat.
Vinegar is made from acetic acid, which is full of Hydrogen ions (H+). These positively-charged Hydrogen ions react with the iron in the nail by taking its negatively-charged electrons, and they become Hydrogen molecules instead (H2). Hydrogen is a gas at room temperature, so it forms bubbles in the vinegar.