Exercises

 

 

 

 

 

 

 

 

 


Does water always boil at 100°C ?

It’s true that 100°C is a temperature often associated with boiling water. However, boiling doesn’t always necessarily take place at 100°C. Let’s take an example

You’ve decided to have a meal on the beach, and you’re going to prepare hard- boiled eggs. You get your saucepan and your stove in order to boil the water.

You light the stove, and away you go. All you have to do is wait. When the water starts to boil, you place the eggs in the saucepan. Ten minutes later, the eggs are ready, and you turn the stove off. When you eat the eggs, they’re cooked. Great!

 

A few days later, your journey takes you into the mountains. Eager to exercise your expertise in boiling eggs, you get out the saucepan, the stove and your lighter.

When the water starts to boil, you place the eggs in the pan. Ten minutes later, you turn off the stove. Logically, the eggs should now be ready.

When you actually try the eggs, you discover that the yellows are soft, although you’ve left them in the boiling water for 10 minutes, exactly as you had done on the beach!

EXERCISE : How do you explain this ? Do you have any ideas how it happened ?

(Solution : Refribase Manual pages 27 to 30)

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