Ionizing radiation and plant growth
The materials required for this science fair project:
- X-ray machine
- 40 green beans
- 4 pots
- Sufficient soil for the 4 pots
- 1 ruler
- Water for the plants
1. For this science project, the independent variable is the length of time during which the seeds are exposed to X-ray. The dependent variable is the height of the bean sprouts. This is determined by measuring the length of the bean sprouts with a ruler. The constants (control variables) are the type of radiation used, the type of seeds used, the amount of water and the type of soil used.
2. Permission is obtained from a a diagnostic laboratory, for the use of an X-ray machine in order to expose the green beans to X- ray radiation. The assistance of the clinic radiologist is also required, to help operate the X-ray machine.
3. The 4 pots are marked pot A, pot B, pot C and pot D before filling them with soil.
4. The 40 green beans are separated into 4 groups of 10 each. The first group of 10 beans is placed in pot A. The second group of 10 green beans are exposed to X-rays (low intensity) for 1 second and then placed in pot B. The third and fourth groups of beans are given 10 seconds and 100 seconds of exposure (at the same intensity as that given to the second group) before placing them in pots C and D
5. The pots are watered daily for the next 8 days. The number of seeds germinating in the pots and the height of the sprouts are observed. The height of each sprout in the pot is measured using the ruler. The heights of the sprouts in each pot are totaled and divided by the number of sprouts, to obtain the average height. The calculated average heights are recorded in the table given below.