There are 9 identical looking balls, but one ball is slightly heavier than the others. If you have one scale, what is the least number of measurements one would need to identify for sure, which ball is the heavier one?

Question

Trojan · Accepted Answer

Can be done in 2 shots. Think it around or else I'll post it later.

Anonymous · Answer

Place 3 balls on each side of the scale and leave 3 off. 
Next take two of the three balls from the heavier side (or 2 from the 3 left out originally if the balance is equal) and put one on each side of the balance and leave 1 off.
If the balance is unequal you've found the heavy ball, if the balance is equal the heavy ball is the 1 you didn't weigh.

Marshy · Answer

Can you explain this?

David · Answer

How can this answer be 2?

Anonymous · Answer

If you grab one of the 8 identical weight and happen to grab the heavier ball by chance it could be done in two measurements. The deviation would be detected by the scale. It said the least not what is the most likely or probable number

Anonymous · Answer

Two. Best if you figured it out alone rather than me to explain :P

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