This project looks at how the temperature of an experiment can affect its reaction time. The purpose of this experiment is to determine if dissolving reactions are affected by waters temperature. I believe that if the H2O temperature increases, then the Alka-Seltzer tablet will dissolve faster because the hot water molecules will move faster colliding with the tablet particles. Water will be the independent variable due to the fact is will always stay in its same form throughout the experiment. The Manipulated variable will also be the water, since I will be changing its temperature. The Responding the variable will be the timing of how fast or slow the Alka-Seltzer tablet dissolves. And the control is the glass of water that is set at cold tap water.
The project will involve the testing of three different water temperatures. One at hot tap water, one at cold tap water, and ice water. 1 cup of water at each temperature will be poured into the same glass, and have its temperature recorded. After doing so each water temperature will go through five trials with one Alka-Seltzer tablet being dropped into the glass each time, recording how long it takes for the tablet to dissolve.
After testing my hypothesis, my results were proven right. When comparing how the Alka-Seltzer tablet dissolved in the hot temperature water and how it dissolved in the cold temperature water. It showed that the hotter the temperature of the H2O was the faster the Alka-Seltzer tablet dissolved.
Materials and Equipment:
Alka-Seltzer tablets (at least 12; if you plan to do additional variations to the project, you will want to get a larger box) Thermometer with a range of at least 0°C to 60°C
Clear drinking glass or jar (12 ounce [355 mL] or larger)
Graduated cylinder, 100 mL. A 100 mL graduated cylinder
Something to stir with, such as a spoon or a chopstick
Hot and cold tap water
Stopwatch or a clock or watch with a second hand
1. Prepare a drinking glass that is marked at the 250 ml point. This glass will used for multiple trials, so it is convenient to mark the desired water level. a. Add 250 mL or 1 cup of water to the drinking glass
b. Use a piece of masking tape on the outside of the glass to mark the water level, placing it with its top edge, even with the water level in the glass. c. Warning: Do not fill the glass completely full because the bicarbonate reaction will produce bubbles that could splash out. 2. Fill the drinking glass with the same volume of water at three different temperatures: Hot tap water, cold tap water, and ice water. a. For the hot and cold tap water, run the water until temperature stabilizes. Fill glass with water to the level of the masking tape. b. For ice water, fill the glass with about half full with ice cubes, then add cold tap water to a bit above the level of the masking tape. Stir for a minute or two so that the temperature is stabilized. Once stabilized, remove ice cubes from water’s surface using a spoon immediately before adding the Alka-Seltzer tablets. Also pour any extra water so that the water is up to level with masking tape. 3. Prepare the drinking glass with one of the three temperatures as described in step 2. Then measure the reaction time for that temperature. a. After filling the glass up to masking tape, measure the temperature and record data. Then remove thermometer. b. Once finished with that, get prepared with the stop watch and the Alka-Seltzer tablet. Once starting the stop watch, the Alka-Seltzer tablet should be dropped in the water. c. Bubbles of CO2 will begin to stream out from the tablet.
d. Stir the water gently and steadily. Use the same stirring method and speed used for all experimental trials. The tablet will begin to disintegrate. e. Once the Alka-Seltzer tablet is completely dissolved in the water, stop the stop watch and record data. 4. Repeat step 3, five more...
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