Accel. Chem. Blog 2

Motion of Particles in Matter

               One of the main areas we covered in this unit was the movement of particles.  The first demonstration used we named "Stink Spray."  When an aerosol can with scented spray was released the odor slowly became apparent to the class.  Starting with people in the front noticing it then heading back.  This demo illustrated how particles travel with other particles similar to diffusion. We also used an experiment using hot and cold water.  When food color was dropped into the two temperatures of water it spread out faster in the warm water.  This is because the warm water has more energy thus moving faster.  We ended this concept with an online simulation similar to the image above, that showed how particles exchanged energy when in motion.  Gas particles roam freely, liquid particles "roll" around each other, and solid particles vibrate.

               The other main concept we covered, in my opinion, was gas pressure.  We did a lab where we inflated a garbage bag with a person on top to show how the particles expand lifting the person.  When the particles hit the side of the garbage bag it pushes the sides out causing it to expand.  We also did a lab where we heated water and alcohol to see how it expands with heat.  One of the other labs, which I thought was important,  demonstrated how an barometer works.  A tube filled with mercury sits in a dish that also has mercury in it. The pressure on that mercury causes the level in the tube to raise or lower showing the air pressure.

               Overall I think we covered some good topics this unit.  The demonstrations and labs we used did a good job of giving a visual.  Everything was well explained and even fun to learn about.