Riddles II

Another set of riddles to get your logic working! :)

The solutions are within the asterisks, just highlight them to see if you're right.

Check out my Megapost of over 220 riddles here: http://braintaming.blogspot.com/2014/03/over-220-riddles-and-brainteasers-to.html

Bulbs
There are three switches downstairs. Each corresponds to one of the three light bulbs in the attic. You can turn the switches on and off and leave them in any position.
How would you identify which switch corresponds to which light bulb, if you are only allowed one trip upstairs?

*Keep the first bulb switched on for a few minutes. It gets warm, right? So all you have to do then is ... switch it off, switch another one on, walk into the room with bulbs, touch them and tell which one was switched on as the first one (the warm one) and the others can be easily identified *




Climbing Snail
A snail is at the bottom of a 20 meters deep pit. Every day the snail climbs 5 meters upwards, but at night it slides 4 meters back downwards.
How many days does it take before the snail reaches the top of the pit?

*On the first day, the snail reaches a height of 5 meters and slides down 4 meters at night, and thus ends at a height of 1 meter.
On the second day, he reaches 6 meters, but slides back to 2 meters.
On the third day, he reaches 7 meters, but slides back to 3 meters.
On the fifteenth day, he reaches 19 meters, but slides back to 15 meters.
On the sixteenth day, he reaches 20 meters, so now he is at the top of the pit!
The snail reaches the top of the pit on the 16th day!*

A Ping-Pong Ball in a Hole
Your last good ping-pong ball fell down into a narrow metal pipe imbedded in concrete one foot deep.
How can you get it out undamaged, if all the tools you have are your tennis paddle, your shoe-laces, and your plastic water bottle, which does not fit into the pipe?

*The random objects lying about are no good, ignore them. You need liquid tomake the ball float to the surface.*

Virile Microbes
A Petri dish hosts a healthy colony of bacteria. Once a minute every bacterium divides into two. The colony was founded by a single cell at noon. At exactly 12:43 (43 minutes later) the Petri dish was half full.
At what time will the dish be full?

*The dish will be full at 12:44.*
The Ball
You throw a ball as hard as you can away from you, but it always returns without hitting anything and is not attatched to anything. How is this possible?

*You're throwing the ball straight up*