Manon D S Page3

Bouncing fluorescent eggs ! How is that possible ?

1. Tools : - black light / - bowl / - jar

2. Protection : - glove / - blouse / - glasses of security

3. Material/solution required : - vinegar / - highlighter / - egg

4. Time required : 48 hours reaction time, to let the eggshell dissolve in the vinegar.

5. Objectives/Goal : A dissolution phenomenon ? In order to discover the main characteristics of the inner film of the egg.

6. Risks / dangers possible : Danger of splashing if the egg is bounced too high. Stains on your hands if you are not wearing a glove when removing ink from the highlighter.

7. Preventive measures against certain risks : Wear a blouse and glasses of security to avoid splashing and wear gloves so you don't stain your hands.

8. The Hypothesis : What are the factors that affect the rebound of an egg ? By soaking an egg in vinegar, the acid contained in the vinegar will dissolve the shell and only a smooth egg will remain.

9. Handling : The first step is to remove the ink from the inside of you highlighter then place it in the bowl and pour some of vinegar over the top when you've made sure that the inside of the highlighter is completely covered use your gloves to squeeze the highlighter, you'll see that it starts to change the color of the vinegar do this for a couple of minutes, then take your jar and place the egg inside. Pour your mixture of highlighter and vinegar inside the jar and then pour vinegar inside the jar until the egg is completely covered. Set the jar aside and leave it for 48 hours.

10. Result : After 48 hours, the eggshell looks completely different.

11. The analysis : The vinegar has dissolved the eggshell. The eggshell is made of calcium carbonate and the carbonate calcium will react with the vinegar which is an acid. When they react together, small bubbles form as you can see and they are CO2 bubbles (see picture 1). That's why you get an egg without a shell where you can only see its membrane. It is transparent, soft, bouncy and even fluorescent ! (see picture 2)

12. The Conclusion : To conclude, by reacting the eggshell with the vinegar, we made a chemical reaction. The eggshell is one of the reagents that gradually disappears. Only the soft inner film remains (the membrane) : it is this film that will allow the shellless egg to bounce and therefore be less fragile without its shell. However, do not bounce the egg too high or the membrane may break (see picture 3).

_Ne pas effacer SVP_