| Complexity level: | 7 |
| Project cost ($): | 30 |
| Time required: | 1 hour to prepare, 1 hour for observation |
| Material availability: | Easily found |
| Safety concerns: | Basic safety requirements |
Hypothesis
Cell phone radiation do not contain enough energy to increase the temperature of water in a test tube.
Overview
Cell phone radiation
The number of cell phone users around the world has increased at an enormous rate since the introduction of the cell phone in the 90s. There are more than 4.3 billion cell phone users around the world (as of June 2009). However, a lot of concern has been raised regarding the amount of radiation emitted by cell phones and the short and long-term effects of cell phone radiation on the health of the cell phone user.
Radiation emitted by cell phones exist in the form of electromagnetic waves. These are radio waves that fall within the range of microwave signals. Microwave radiation can cause dielectric heating of dielectric material, which includes human tissue. Therefore, it is theoretically possible for radiation from cell phones to increase the temperature of the cells on the surface of our head, when we use cell phones. This increase in tissue temperature is however, very minimal and should be able to be regulated by blood flow.
The tissue on the surface of our head will absorb some of these radio signals. Since the maximum power that a cell phone can generate is well below 4 watts, the radio signals might make our skin slightly warmer but they should not cause any tissue damage.
Scientific Terms
Materials
The materials required for the science fair project:
- An Ericsson cell phone
- A Nokia cell phone
- A Motorola cell phone
- 3 test tubes
- 30 ml of water
- A measurement cylinder
- 3 thermometers
- A stopwatch
Procedure
1. For this science fair project, the independent variable is the brand and model of the cell phones used for this experiment. The dependent variable is the temperature of the water in the test tube. This is determined by using a thermometer to measure the water temperature. The constants (control variables) are the amount of water in the test tube, the length of time the cell phone rings, and the room temperature.
2. The experiment is carried out with 3 brands of cell phones manufactured by Ericsson, Nokia and Motorola. One cell phone (any model) from each manufacturer will be tested.
3. The test tube is filled with 10ml of water and a thermometer is placed inside the test tube. The initial temperature of the water is measured and recorded in the table below.
4. The cell phone to be tested is placed on the table and the test tube is brought as close as possible to the cell phone’s antenna. The cell phone’s number is dialed from another phone and the cell phone is left to ring continuously for 2 minutes. After 2 minutes, the temperature of the water is measured and recorded in the table given below.
5. Procedures 3 and 4 are repeated using cell phones from the other 2 manufacturers. The water temperatures are measured and recorded in the table given below.
Results
It is observed that the temperature of the water in the test tubes did not increase after the cell phone from the 3 manufacturers was left ringing for 2 minutes.
| Condition | Effect of cell phone radiation on water temperature (degrees Celcius) | ||
| Ericsson | Nokia | Motorola | |
| Before ringing | 24.5 | 24.5 | 24.5 |
| After ringing | 24.5 | 24.5 | 24.5 |
Conclusion
The hypothesis that radiation emitted by a cell phone emits enough energy to increase the temperature of water in a test tube is proven to be incorrect.
Many studies have been done to determine if radiation from a cell phone can cause health problems. Most of the studies completed were able to show that using the cell phone does not cause cancer or other health problems. However, it is still advisable to minimize exposure to cell phone radiation by using hands free devices, earphones or Bluetooth devices.
Also consider
Try repeating the science fair project by using other cell phone models and brands.
The experiment can also be done to determine if the temperature increases during cell phone conversations (as opposed to simply ringing).
References
Mobile phone radiation and health - http://en.wikipedia.org/wiki/Mobile_phone_radiation_and_health
Physicist debunks cell phone viral ad - http://www.wired.com/underwire/2008/06/cellphones-cant/
