Tuesday, 29 July 2014

Effect of Orange Juice on Egg

When a raw egg with the shell on is submersed in orange juice for a few days, the acid in the juice will break down the calcium in the shell. The membrane underneath the shell will help the egg retain its shape. It will result in a rubbery egg. Be careful if you try to pick it up. Your finger can punch easily through the egg in its softened state and can be quite a mess.

Wednesday, 23 July 2014

Orange Juice effect on Teeth

The lower the number, the more acidic a substance is. Compared to orange juice, cranberry, lemon and lime juice all have lower pH, ranging from 2 to 2.6. Most colas; apple, pineapple and grapefruit juices; and teas have a pH ranging from 2.5 to 4. Orange juice also has a high sugar content; sugars feed bacteria found in plaque that builds up on tooth enamel. As bacteria break down the sugar, they produce a by-product with a high acid content, which further damages the tooth enamel. Orange juice is also high in sugar, which converts to acid in the mouth, and contributes to tooth decay according to a report from Elmhurst College.

Why does an egg become heavier when soaked in vinegar?

Hypotonic means lower concentration, hyper-tonic means higher concentration. 
Osmosis is movement of water from the area of greater solute concentration to the area of lower solute concentration. Then, just as you said, if the egg is heavier then it was when you started it had to absorb water from the vinegar solution it has been soaking in. The rule of thumb is the water follows the concentration. It goes where the concentration is higher; moving from hypotonic to hypertonic solution, or from vinegar solution into the egg. 

If the solution were hyper-tonic, then the concentration of solute(dissolved particles) would be greater outside the egg. So the water would move to the outside of the egg, to kind of make the outside solution less concentrated. The water would continue to move out of the egg until the concentration of particles inside the egg is equalized with the concentration of particles outside of it. In the end, the egg would lose water and weight less. 
However, if the solution is hypo-tonic this would mean that concentration outside the egg is lower then the concentration inside the egg. So, the water will move from area of lower particle concentration to the area of greater particle concentration. In your egg's case inside the egg. 
The egg is hyper-tonic to the solution; and solution is hypo-tonic to the egg. 

Wednesday, 16 July 2014

Video on corals

Study on Acid effect on Coral Reefs

The world’s coral reefs face almost certain death as increasing amounts of carbon dioxide in the atmosphere are absorbed by the oceans, acidifying the water in which corals live, a new study warns.

As carbon dioxide is emitted through the burning of fossil fuels, some of it is absorbed by the world’s oceans. When the carbon dioxide is absorbed in the water, it produces carbonic acid, the same acid that gives soft drinks their fizz. This acid also makes certain minerals dissolve more readily in seawater, particularly aragonite, the mineral used by corals and many other marine organisms to grow their skeletons.

At greatest risk of these changes are Australia’s iconic Great Barrier Reef, the world's largest living structure, and the reefs of the Caribbean Sea.

To slow ocean acidification, scientists warn, that it  will likely take more stringent and immediate reductions in carbon dioxide than would be needed to reduce the other effects of global warming. 

A Video On Eggs and Osmosis:

Literature Review 3

Why does an egg become bouncy when submerged in vinegar?

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.