Experiment: Chemical Kinetic Glowsticks

• what does heating a reaction do?

  increases its rate because the molecules move faster and so collide more frequently.
• what does cooling a reaction do?

  decreases its rate because the molecules move slower and so collide less frequently.
• what do you need?

  • glow sticks
  • a transparent pudding bowl
  • ice
  • hot tap water
• what is method 1?

  1. fill a pudding bowl with ice cubes, water and salt. The salt is to reduce the temperature.
  2. break and shake a glow stick then place it into the pudding bowl so the lower half is submerged in the water and the upper half is outside.
  3. after a few minutes, notice how the lower half isn't as bright as the upper half due to the coldness.
• what is method 2?

  1. take 2 glow sticks, break and shake them then put one in the freezer and the other in a bowl of hot water.
  2. leave for five minutes then remove them and compare the brightness of the glow sticks, the freezer glow stick will be dimmer.
  3. place the freezer glow stick in the hot water and watch how the brightness increases as it gets hotter.
• what's happening here?


  the brightness of the glow sticks is directly proportional to the temperature as reactions get faster as they get hotter and slower as they get colder.
• why do we freeze food?

  freezing food allows it to be kept longer because the reactions within it which would normally cause it to spoil are slowed down by the lower temperature.