Heating water with a burning Cheeto introduces students to calorimetry.
Curriculum Notes
This demo serves as a good introduction to thermochemistry in the "Introduction to Chemistry" course - or a good closing demonstration for thermochemistry in the General Chemistry I course. Particularly the following concepts are illustrated: heat loss + heat gain = 0; All foods contain chemical compounds, when food burns it releases energy (heat and light) due to bonds breaking and bonds forming; chemical bonds contain stored energy (potential energy), a calorimetry experiment can be run to determine the amount of calories in food; 1.00 Food Calorie = 1,000 science calories; combustion reactions generate heat.
One day of lead time is required for this project.
Preparation
On ring stand there will be two clamps. On the bottom clamp use the buret clamp to hold the 50ml beaker. On the top clamp use the three fingered clamp to hold the Vernier stainless steel thermometer probe that is connected to the GoLink! interface. This plugs into the usb port of computer with appropriate Vernier software. Place watch glass under beaker to catch ashes.t
Materials
- Vernier stainless steel thermometer probe and a GoLink! interface
- Bag of Cheetos
- Computer with Vernier with Logger software (dongle if using mac)
- RGB cable
- Lighter
- Forceps
- Large watch glass
- Ring stand and two ring stand clamps
- Small 3 fingered clamp
- Burette clamp
- 50 ml beaker
- Small bottle of DI water
Procedure
Load logger software and expand the temperature reading to fit the full screen. Use forceps to hold Cheeto and light on fire. Hold burning Cheeto under the 50 mL beaker and monitor the increase in temperature.
Table 1 Data for water during the Combustion of a Cheeto | |||
Mass of Water | Initial Temperature | Final Temperature | Change in Temperature |
Safety Precautions
Since fire is involved keep paper and other flammable materials clear of demo space and be sure that you have a fire extinguisher readily available. Make sure that the watch glass is placed under the burning Cheeto to catch falling pieces.
The video below is a very exciting, but dangerous variation of the Cheeto Calorimetry demo. Please note that the demonstrator has not aken nearly enough safety precautions. Only experienced demonstrators should try this variation and the should put more extensive safety measures in place, e.g., doing the demo outside!