Experimental design

Experimental Design

List the materials you used in your experiment. Include technologies you used (e.g., scientific equipment, internet resources, computer programs, multimedia, etc.).

• 16.9 oz. water bottles
• newspaper
• tape
• string
• 1 gallon milk jugs
• Hobart school refrigerator
• tap water
• thermometers
• stopwatch
• chartgo.com

Identify the control group, independent variables and dependent variables in your experiments.

The control group is the milk jug filled with water and not in an insulating cylinder. The independent variables are the insulating cylinders (one of water bottles and one of newspaper-stuffed water bottles) and the dependent variable is the temperature of the water after being in the refrigerator.

What was your experimental process? Include each of the steps in your experiment and the safety precautions your team used.

Step 1 - Collection:

Receiving bottles collected by the YMCA

Our school and the YMCA assisted in the collection of 600+ water bottles. 

Step 2 - Assembly:

Stringing the water bottles and stuffing them

We assembled the 2 water bottle cylinders by cutting the bottoms off of each water bottle and lacing them with a string so that the top of one bottle could fit into the bottom of the next. The string could be tightened and then tied off with a cap. In the one structure, we stuffed newspaper into the bottles before pulling the string tight. In the other there was no newspaper. We called each tube of bottles a "log". We placed the logs side by side to form a cylinder. We used packaging tape to hold the cylinder together. It was hollow in the center and long enough to hold 3 milk jugs. The end two jugs were to seal the cylinder, and the center one was full of water (room temperature to begin, ~63F).

Step 3 - Testing:

(1) Control group

(2) water bottles only

(3) newspaper-stuffed

We filled 3 milk jugs with tap water and set them on the counter.  After four hours, we took the temperature of the water that had been sitting at room temperature (~63F). We put two milk jugs into the water bottle cylinders (#2 and #3). We inserted our control group and the two other cylinders into the large school refrigerator. We tested the temperatures of the three groups every half hour.

On day 1, our results after the first 30 minutes were:
Control:                                                                      = 42 degrees Fahrenheit
Water bottle cylinder without newspaper lining: = 50F
Newspaper-stuffed cylinder:                                  = 62F

We continued to check the temperatures at 60 and 90 minutes and then we graphed them. We did this on three different days. As this first test indicates, the newspaper-stuffed cylinder lost the least amount of heat.