What does an exclamation mark mean?

The exclamation mark is used to end a sentence or short phrace which expresses very stong feelings. For exampe: 1.thats fantastic!

2.Johnny, don't touch that!

3.help!

4.Good heavens!

Exclamation mark sentences normaly begin with "what" or "how". an exclamation mark it can show that a statement is very surprising. For example

After week of work ,the scientists finally opened the tomb. If was empty!