you can make anything that comes to mind. Use that imagination!
The answer is yes. You can definitely make a floating raft out of plastic water bottles. You would have to make sure that you had enough plastic bottles to complete the task. For step by step instructions visit http://www.wikihow.com/Make-a-Raft-out-of-Plastic-Bottles.
Plastic.
People usually remove the caps on plastic bottles specially on festivals so as to make the water bottle less painful as the water leaks out.
about 2.7 million tons.
plastic
Because there are really bad chemicals in plastic. Don't freeze water bottles or leave them out in the sun because the chemicals leak into the water that you consume.
plastic water bottle density
Plastic bottles that are empty may be harder to find in bulk. Most companies make their own bottles with their own materials. However you can buy just some regular water and drain it and use the bottles.
for drinking with a liquid thing like a water
if you mean plastic bottles then a little robot but it will take time to make.
refill it with water
yes