Balloon in a Bottle

Can you blow up a balloon in a bottle?

Materials needed:

bullettwo one-liter soda bottles
bullettwo balloons with wide openings
bulletnail

Instructions:

bulletUsing the nail, punch a small hole in one of the bottles, about five centimeters from the bottom.
bulletInsert an uninflated balloon into each bottle, stretching the opening of the balloon over the mouth of the bottle.  Do you think you will be able to blow up the balloons inside the bottles? Why or why not?
bulletTry blowing up the balloons. What happens? Can you explain your results in terms of air pressure?
bulletNow fully inflate the balloon inside the bottle with the hole.  When you are done, hold your finger over the opening.  What do you think will happen when you remove your finger?  Try it.
bulletInflate the balloon again, holding your finger over the hole.  Now fill the inflated balloon with water.  If you remove your finger, do you think the increase in air pressure as the air enters the hole will be strong enough to push the water out?  Try it and see.

The Heavy Paper

Materials needed:

bulletruler
bulletlarge sheet of paper
bullettable or other flat surface

Instructions:

Position the ruler so that about two-thirds of it is on the table and the remaining third is hanging over the edge.

bulletLay the sheet of paper on the table over the ruler.
bulletHit the overhanging end of the ruler with a downward motion.
bulletCan you make the paper fly into the air?
bulletWhat happens if you change the size of the paper?
bulletExplain your results in terms of pressure.

Pressure Bottle

Materials:

bulletone-liter soda bottle with three small holes punched in it as shown
bulletbottle cap
bulletthree push pins
bulletlarge shallow pan to hold bottle

Instructions:

bulletFill the bottle with water but do not cap it.  Remove the middle pin.  Does any water come out?
bulletNow screw the lid on tightly.  Does water come out now?
bulletLoosen the cap.  What happens?  Why does capping the bottle make a difference?
bulletReplace the middle pin and refill the bottle.  Cap it.  Take out the middle pin and squeeze the bottle.  Does water come out?
bulletSqueeze hard and then lightly.  How does the strength of your squeeze affect the stream of water?
bulletWhen you stop squeezing, watch the hole carefully.  What happens?  Why do you think this happens?
bulletReplace the middle pin and refill the bottle.  Remove all three pins and the cap.  How do the three streams of water differ?  Make a sketch of the bottle and the streams below.
bulletWatch your bottle for a few minutes.  As the level of the water goes down, how do the streams change?  Why do you think this happens?
bulletReplace all three pins and refill the bottle.  Cap it.  Now remove any two of the pins.  What happens?
bulletNow try two other pins.  Try all of the combinations.  Is there any difference between taking the top and bottom pins out and taking the middle and bottom pins out?  Describe the difference.  What do you think causes this difference?