1. Introduction

The purpose of the experiment is to find out what kind of acid affect an egg after ten days. We selected this topic as coral reefs are depleting in the world because of water pollution containing chemicals. They are vulnerable to various chemicals as they are made of calcium carbonate. Since the eggshell is made of calcium carbonate, we can carry out the experiment to find out the results and apply the knowledge to stop chemical pollution in water.
Vinegar is a liquid consisting mainly of acetic acid (CH3COOH) and water. The acetic acid is produced by the fermentation of ethanol by acetic acid bacteria.[1] Vinegar is now mainly used as a cooking ingredient, but historically, as the most easily available mild acid, it had a great variety of industrial, medical, and domestic uses, some of which are still promoted today.
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbo  nate is the active ingredient in agricultural lime, and is created when Ca ions in hard water react with carbonate ions creating limescale. It is commonly used medicinally as a calcium supplement or as an antacid, but excessive consumption can be hazardous.
When you submerge an egg in vinegar, the shell dissolves. Vinegar contains acetic acid, which breaks apart the solid calcium carbonate crystals that makes up the eggshell into their calcium and carbonate parts. The calcium ions float free, while the carbonate goes to make carbon dioxide—the bubbles that you see. And that is why it is translucent and its membrane flexes when you squeeze it, thus making it bouncy.

According to Steve Spangler, n.d Vinegar is an acid called acetic acid - CH3COOH - and white vinegar from the grocery store is usually about 5% acetic acid and 95% water. Egg shells are made up of calcium carbonate. The vinegar reacts with the calcium carbonate by breaking the chemical into its calcium and carbonate parts. Some of the vinegar will also sneak through, or permeate, the egg's membrane and cause the egg to get a little bigger. This flow of a liquid from one solution through a semipermeable membrane and into another less concentrated solution is called osmosis. That's why the egg is even more delicate if you handle it. If you shake the egg, you can see the yolk sloshing around in the egg white. If  the membrane breaks, the egg's insides will spill out into the vinegar allowing the egg to react with the carbon dioxide in the air will cause the egg to harden again.

Research Question
The research question we have chosen is “What is the effect of different substances on an egg after certain periods of time?”

Hypothesis
The hypothesis is that the egg will turn bouncy after a few days and the shell will be dissolve in the vinegar.
For the soda, we think it will take much longer to dissolve the eggshell.


Independent Variables
- No. of eggsDisplaying 20140730_091103.jpg
- Amount of vinegar/soda
- Type of substance
- Time egg is submerged

Dependent Variable
- Surrounding temperature

Constants
- Type of egg
- Type of container

- No. of eggs per container


No comments:

Post a Comment