Boyle’s Law

 Start with the plunger all the way into the syringe. Try pulling out and pushing in the plunger. Now “plug the end” with your finger and try to pull and push the plunger  Record on your paper what you notice about each situation. Step 1) no airUnpluggedPlugged with finger Push plunger in Pull plunger out

 Now pull out the plunger so there is some air in the syringe. Try pushing in the plunger and pulling out the plunger.  Repeat but this time plug the opening with your finger first. Step 2) AirUnpluggedPlugged with finger Push plunger in Pull plunger out

 Take two marshmallows and draw a face on each  Remove the plunger from the syringe  Place one marshmallow in the syringe and replace the plunger  Push in the plunger to force out as much air as possible without squeezing the marshmallow

 Plug the syringe with your finger  Pull on the plunger, hold it in the “out” position and record your observations  Predict what will happen when you release the plunger. Record  Release the plunger and record your observations  Repeat several times so everyone gets a chance to “play”

 Boyle’s law states that volume of a gas varies INVERSELY with pressure at constant temperature and constant number of gas molecules.  If pressure decreases (pull plunger out) = volume increases (marshmallow got bigger)  If pressure increases (push plunger in) = volume decreases (marshmallow got smaller)

 When discussing gases, one must always specify the  Temperature  Volume  Pressure  Quantity (number of molecules) All of these will affect the way the gases behave.

 Imagine a marshmallow sealed on Earth in a steel container at 1 atm pressure. Predict what change (if any) would occur in the volume of the marshmallow if the container were opened in each of the following situations (assuming not temperature change):  1. In a space shuttle: weightless but pressurized at 1 atm  2. On a space walk: weightless with 0 atm pressure  3. On a deep-sea dive: at a depth of 1000 ft which 4 atm of pressure