March 27, 2012
Marshmallow: The Snack That Acts Like A Gas Objective: Record and observe marshmallow and compare it to Boyle’s law. Materials:
-2 mini marshmallows
1. Take out marshmallow.
2. Draw face on marshmallow.
3. Open stopcock.
4. Pull plunger out.
5. Put marhmallow in syringe.
6. Put plunger back into syringe.
7. Push plunger so it’s barely touching the marshmallow. 8. Pull plunger back and record observations.
9. Remove marshmallow and replace it with the second marshmallow. 10. Close stopcock and push plunger so it’s barely touching the marshmallow again. 11. Record observations.
Trial| Open| Closed|
1 (without marshmallow)| Nothing, Easy to push.| Nothing happened.| 2| Nothing, Easy to push.| Marshmallow got bigger.|
3| Nothing, Easy to push.| Marshmallow got bigger.|
4| Nothing, Easy to push.| Marshmallow got bigger.|
5| Nothing, Easy to push.| Marshmallow got bigger.|
Every time you push with the marshmallow in the tube, the air inside the marshmallow is released. The marshmallow decreases in size.
Boyle’s law states that for a fixed amount a gas at a fixed temperature volume is opposite to its pressure. The air in the marshmallow is what follows Boyle’s law. The marshmallow is similar to a gas because when the pressure in the syringe is decreased the pressure in the marshmallow is increased. The volume increases in the marshmallow. So basically when the plunger is pulled out the pressure in the syringe decreases and the volume of the marshmallow increases.