Experimental method, investigation method

Third, the research process

Experimental equipment: vinegar, water, hydrochloric acid, a number of eggs, a number of glasses.

Experiment one The experiment of eggs and vinegar

Experiment record: first, put the eggs into the cup, pour the vinegar to full over the eggs. My sister and I from time to time with a small hand to press the egg, a day has passed, the egg is still very hard, there is no change. We were a little disappointed. "So what dad said was wrong too!" My sister said in frustration. I said, "Even though the eggshells are still so hard, let's wait two more days and see since we tried." "Okay!" My sister agreed.

On the morning of the third day, we were surprised to find that the egg had really softened, and when we reached out and carefully touched it, it was still soft.

What does it have to do with the eggs getting soft if the vinegar gets watered down?

Experiment 2: Eggs and watered-down vinegar

Experiment record: Half of the water and half of the vinegar were put into the cups, and the eggshells were not softened after a week. 10 days later, the eggs were observed again, and the surface of the eggshells changed, and the eggshells were softer when compared to the original ones when touched by the hand.

Then I think: eggs with vinegar can be softened, if soaked in other liquids can be softened?

Experiment 3: eggs and hydrochloric acid experiment

Experiment Record: put the eggs into the cup with hydrochloric acid, three minutes after the eggs began to float up and down, the surface of the eggshell dense bubbles, six hours after the eggs sank to the bottom of the cup, the eggs with chopsticks to poke the surface of the eggs, found that this time the surface of the shells have been completely softened.

Experiment 4: egg and water experiments

Experiment Record: put the egg into a cup of water, the egg immediately sank to the bottom of the cup, a week later to observe, the surface of the egg did not have any change, half a month after the eggshell is still the original that hard.

Four, experimental analysis

Based on the above experimental observations, organized as follows:

Eggs immersed in a variety of liquids in the experimental record table

Materials

Time

phenomena

Eggs, vinegar

3 days

Egg shells on the small air bubbles, soften

Eggs, water, vinegar

Eggs, water, vinegar

Eggs. Water, vinegar

10 days

Eggshell slightly softened

Eggs, hydrochloric acid

6 hours

Eggshells softened

Eggs, water

14 days

No softening

Based on the experimental phenomena, I hypothesized that the reason for the egg's softening was: first, it had something to do with the nature of the liquid; and second, it had something to do the time it was stored in the liquid; and thirdly, it is related to the concentration of the liquid.

Through the search for information, I learned that: the main component of the eggshell is made of calcium carbonate, calcium carbonate meets acid to produce a chemical reaction, at the same time will produce carbon dioxide, so the surface of the egg will produce bubbles, and make the eggshell soft.

There is no change when the egg is with water, because water is neutral and calcium carbonate cannot react with water. Eggs and vinegar, eggs and vinegar to water, the reason why the former takes less time than the latter is because the concentration of the former is greater than that of the latter, so that the softening of the egg is related to the nature of the liquid being acidic or not, and the length of time it takes to soften is related to the concentration of the acidic liquid.

Fifth, the research experience

Through the study, I understand the reason for the softening of the egg, many things they can only try to really understand the reasoning contained therein.