Dissolving Egg Shells!
Key Concepts
Materials:
1 cup Diet coke
1 cup Vinegar
1 cup Coffee
1 cup Orange Juice
1 cup Water
5* Eggs (raw or boiled)
5* glasses
1 sharpie
5* slips of paper
Optional: Rubber gloves
Note 1: Don’t worry if you don’t have all of the liquids above! If you only have 3 of the liquids, you only need 3 eggs, 3 glasses, and 3 slips of paper.
Note 2: Plastic cups will work fine as well.
Activity Directions:
Additional Experimentation:
- Take your sharpie and write out “diet coke”, “vinegar”, “coffee”, “orange juice”, and “water” on each of the 5 slips of paper. Each slip of paper should contain the name of 1 different liquid. If you don’t have all 5 liquids, you can skip over the liquids that you don’t have.
- Arrange the slips in a single row, side by side. Take 5 glasses and place them behind the slips of paper.
- Place 1 egg in each glass.
- Fill each of the 5 glasses or plastic cups with 1 cup of each liquid.
- Wait 1 day.
- If you have rubber gloves, you can put them on to avoid getting your hands dirty.
- Starting with the cup of water, take the egg out and examine it. Is it the same color? Is it the same hardness?
- Place the egg on a plate
- Repeat steps 7 and 8 for each of the 4 other cups of liquids.
- Make sure to clean up! Pour out all of the liquids, wash the glasses, and wipe down the table.
- Why does the egg placed in vinegar become soft?
- Eggshells contain a compound called calcium carbonate which is basic, while vinegar (acetic acid) is acidic. When an acid and base meet, they react! The egg shell dissolves and the soft inner membrane of the egg is left, resulting in the egg being soft.
- Eggshells contain a compound called calcium carbonate which is basic, while vinegar (acetic acid) is acidic. When an acid and base meet, they react! The egg shell dissolves and the soft inner membrane of the egg is left, resulting in the egg being soft.
- Was this a chemical reaction? And if so, why?
- A chemical reaction occurs when the molecular bonds of a substance change. Changing the physical properties of a substance, such as state of matter, isn’t a chemical reaction because the substance is still the same. Some common examples of each include: burning wood (chemical), cooking an egg (chemical), iron rusting (chemical), ice melting (physical), cutting paper(physical), mixing play-doh (physical).
- A chemical reaction happens because the bonds in the calcium carbonate in the egg shell are being broken and the calcium carbonate is being changed into new substances.
- A chemical reaction occurs when the molecular bonds of a substance change. Changing the physical properties of a substance, such as state of matter, isn’t a chemical reaction because the substance is still the same. Some common examples of each include: burning wood (chemical), cooking an egg (chemical), iron rusting (chemical), ice melting (physical), cutting paper(physical), mixing play-doh (physical).
- Why did bubbles form in the cup with egg and vinegar?
- When vinegar and the egg shell react, one of the compounds produced is carbon dioxide gas, the same gas that’s released when soda fizzes!
- When vinegar and the egg shell react, one of the compounds produced is carbon dioxide gas, the same gas that’s released when soda fizzes!
- What is pH and the pH scale?
- pH is a measurement of how strongly acidic or basic a substance is. The pH scale starts at 7, and substances with a pH of 7 are neutral, like water. Substances with a pH less than 7 are acids, while substances with a pH greater than 7 are bases. In fact, the further away a substance’s pH is away from 7, the stronger it is.
- For instance, the pH of milk is about 6.8. On the other hand, the pH of stomach acid is 2.5. Both of these substances would be acids; however, because 2.5 is much further away from 7 than 6.8, stomach acid is a much stronger acid
- pH is a measurement of how strongly acidic or basic a substance is. The pH scale starts at 7, and substances with a pH of 7 are neutral, like water. Substances with a pH less than 7 are acids, while substances with a pH greater than 7 are bases. In fact, the further away a substance’s pH is away from 7, the stronger it is.
- Diet coke and orange juice are also acids—why don’t they dissolve the egg shell too?
- Diet coke has a pH of 3.1, orange juice has a pH of 3.5, and vinegar has a pH of 2.5. Even though all 3 of these substances are acids, vinegar is a much stronger acid than diet coke and orange juice. Therefore, it dissolves the eggshell much faster.
- Diet coke has a pH of 3.1, orange juice has a pH of 3.5, and vinegar has a pH of 2.5. Even though all 3 of these substances are acids, vinegar is a much stronger acid than diet coke and orange juice. Therefore, it dissolves the eggshell much faster.
Additional Experimentation:
- Leave the eggs in for another 24 hours. What do you notice?
- Safely experiment with different liquids other than the ones listed above.
- Notice that the eggs placed in coke and coffee have been stained. Can you brush off the stain with a toothbrush and toothpaste?
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Suggested video: https://www.youtube.com/watch?v=I7hEajj1ILM
Published 6.12.2020
Author: Alex Zhang
