`Air PressureRuthie L. Banks                Carter School                               5740 South Michigan Ave.                               Chicago IL 60637                               (312) 535-0860Objective: Students K-8 will be able to demonstrate the pushing power, or pressure, of air.Materials Needed: Ice                           Cans (pop) Funnel                        Bowl Hot and Cool Water            Candle Graduated Cylinder            Index Card/Flat thin card Plastic Drink Bottle (soft)   Paper Cups  Clay                          Coin Glass Bottle                  Glass        Tissue Paper/Paper TowelStrategy:Ask students:  Did you know that air presses against you at all times?  Tellthem that they will see how air pushes, discover how air's pushing power,or pressure, changes when you heat it, and find out what happens when youreduce the air pressure inside a container.  Explain and demonstrate how airtakes up space.  Display the materials on the table and demonstrate thefollowing activities along with the students.Activities:1.  Paper Plunge:  Crumple a piece of paper and push it into the bottom of a    glass.  Then plunge the glass straight down into the bowl of water.  Ask    the students:           1.  What happens to the paper?           2.  Where is the water level in the glass?    (Tell them) Water can only get into the glass by squashing/compressing the    air inside it.  Air can be compressed, a little, but then it pushes back    and prevents the water from reaching the paper.2.  Cartesian Diver:  Have the students observe the eye dropper.  The    eye dropper will rise and sink.                (Ask them) Why the eye dropper rises and sink?    Explain that when you put the dropper in the water, air becomes trapped     inside the dropper.  When you squeeze the bottle, water compresses the air     and the water takes up more space in the dropper, causing the dropper to     sink.  When you relax your grip on the bottle the air in the dropper top     expands again causing the water to be pushed out of the eye dropper. Then     the dropper floats back to the surface. 3.  Jumping Coin:  First smear some cold water over the coin and over the top of     the bottle.  This will make an airtight seal when you rest the coin on top     of the bottle.  Hold your hands around the bottle and wait for about 30     seconds.  What happens to the coin?  Take your hands off the bottle and wait     again.  What happens to the coin now? 4.  Sticking Together:  Cut a 1.5 cm hole in the middle of the blotting paper,     then wet it thoroughly.  Put a small amount of clay into the paper cup.       Stand a candle in the paper cup.  Tip the cup and light the candle.  Quickly     cover the cup with the wet blotting paper.  Then stand the second cup     upside-down on the top of the first cup, making sure that it fits exactly     over the first cup.  Wait until the flame goes out (about 20 seconds).  Then     lift the top cup gently.  If you have matched their rims exactly, the cups     should stick. 5.  Crushing With Air:  Activity 1 (Bottle)    Stand the bottle upright in a bowl.  Pour the hot water into it and leave it     for a short time.  Screw the top on the bottle.  Lay the bottle in the bowl     and pour ice cold water over it.  Then stand the bottle up.         Activity 2 (Can)    Pour a small amount of water about (5 ml) into the can.  Heat gently over     candle.  When water begins to boil and steam rises from the can, remove from     the heat.  Quickly place the can upside down in the bowl of water.      (Answer)  The can/bottle retains it shape in a normal atmospheric condition,     because the air pressure inside the can/bottle is the same as the air     pressure outside.  The can/bottle collapse as the warm air inside the     can/bottle cools, it exerts less pressure.  The pressure of the air outside     is stronger and crushes the bottle/can.  (Ask students)            1.  What happened?           2.  Which is stronger the pressure of the air outside               or inside the bottle/can?           3.  What made the bottle/can crush?    6.  Seal With Air:  Hold the glass over a bowl.  Carefully pour some water into     the glass.  Place the card on the glass.  Hold it down so the card touches     the rim all the way around.  Still holding the card, turn glass upside down.    Let go of the card.  What happens?  (The water stays in the glass!) Performance Assessment:After completing these activities students will be able to demonstrate various concepts about air; air exists, air has volume, air exerts pressure, hot air rises, and cold air has lower pressure than hot air.  `