Sample #1: Does Temperature Affect the Activity of Fruit Flies?

At a temperature of 3¾C, no flies were active. At 8¾C, 110 fruit flies were active. At 15¾C, 130 fruit flies were active. At 23¾C (room temperature, 130 fruit flies were active. At 31¾C, 130 fruit flies were active. At 40¾C, 99 fruit flies were active.

The original hypothesis stated that no fruit flies would be active at or near 0¾C, and that the number of fruit flies moving would increase as the temperature increased. The results partially support the hypothesis. The results show that the number of fruit flies that are active increases from none at 3¾C to 130 in motion at 31¾C. The number of fruitfliesthat were in motion increased as the temperature increased because they are cold blooded. The chemical reactions that occur in their bodies are dependent up the temperature of their surroundings. Chemical reactions occur more slowly at lower temperatures because the molecules involved are moving slower, thus having a lesser chance of colliding, and colliding with lesser force. The reactions thus slow down. As the temperature increases, the molecules move faster and thus have a greater chance to both collide, and also collide with sufficient force to induce a reaction. Ther reaction increases.

However, the number of flies in motion dropped at 40¾C to 99. It appeared that 31 fruit flies had died due to the hotter temperature. Perhaps the enzymes and proteins making up the structure of their cells became denatured, thus reducing chemical reactions, and eventually killing the flies. This factor had not been taken into account when writing the hypothesis.

Potential Problems with the Procedure and Steps to Improve Each:

1. Only one trial was taken at each temperature. Class results could have been used to increase the validity of the data collection.

2. Several teammates read the temperature from the thermometer. Each teammate could read the thermometer differently. The thermometer should always be viewed from a perpendicular angle. Only one student should read the thermometer, or several students should read the thermometer and reach consensus on the temperature reading.

3. The temperature was read in the water bath. The actual temperature of the test tube in which the fruit flies were kept may have been different. If a one-holed rubber stopper was available, the thermometer could have been inserted through the hole and the stopper and thermometer inserted into the test tube to provide temperature readings that the flies were actually experiencing.

4. There were "wide" gaps in collecting data. The fruit flies were either not active or all active. Testing more temperatures at lower temperatures may have showed how those temperatures affected the flies. Likewise, more temperatures near and above 40¾C could have been tested. If all students started with the same number of fruit flies, the class data could have been used. Each group tested fly activity at different temperatures. Class data could also be used if the data were converted to a ratio of active fruit flies per total number of fruit flies.

5. The definition of fruit fly activity was sometimes difficult to ascertain. At 3¾C, several fruit flies occasionally jerked their legs. Several were perched motionless on the side of the test tube, legs twitching. Were they active? It was noted that fly movements reduced the longer they were exposed to cold temperatures. Likewise, as the temperature warmed up, a number of flies remained motionless (but upright) on the sides of the test tube. Were they active? The test tubes were tapped when this was observed to see if they would move.