Does a salt solution evaporate in the air at a faster rate or slower rate than pure water?
2.
We think that a pure water sample will dissolve faster than a salt water solution because salt adds more mass to equal quantities of liquids.
3.
It took a total of 31hrs. 15 min. to evaporate the pure water and 32hrs. 10 min for the salt water. We noticed a residue of salt on the side and bottom of the salt water tray. Predictably, the salt stayed behind after the water evaporated. Because the salt residue remained moist after the pure water had dissolved for nearly an hour we think that the salt might have prevented the water from total evaporation for an additional 50 minutes. We hadn't anticipated the effect of the salt on evaporation which changes our hypothesis. Mass is not involved in the evaporation process.
4.
We think that the evaporation times were nearly the same. But when the salt water was almost evaporated the higher concentration of salt might have slowed the evaporation process by blocking the air from the moisture.
5.
It took a long time to see much happening. We finally took both dishes outside into the hot sun in order to speed up the evaporation. Since both dishes were exposed to the same conditions we didn't think this would matter. Finally, by the middle of the next day the evaporation was finally complete. If we did it again we would either use less water or larger dishes, so the experiment would move along faster.
6.
In our experiment that will compare how long it will take for 100 ml distilled water to evaporate from a 5" diameter container. This will be the control group. For the experiment group we will use 100 ml of distilled water and dissolve 10 grams of table salt in the water. We will use the same diameter dish for both samples, so the same amount of water surface is exposed to the air. The dishes should be labeled "salt" and "pure". The time should be noted when the water and salt water is poured into the dishes. The dishes should be observed at time intervals to be determined as the experiment progresses. At first the checks could be at 6-hour intervals. As the evaporation nears completion shorter time intervals may be necessary. Note the time of each observation. Materials: distilled water, table salt, mixing container and mixing rod, 2 flat 5" dishes, clock or timer, pad to note check times and observations during experiment.
7.
We poured the water into each 5" dish and set the containers on a table. We noted the time: 8:00 a.m. Saturday. We came back in 6 hours. (2:00 p.m.) Not much water has evaporated. We decided to move both the dishes out into the hot sun at 2:10 p.m. Observed dishes at 8:00 p.m. About a third of the liquid in each tray has evaporated. Observed at 8:00 a.m. Sunday. Half evaporated. Observed 2:00 p.m. Warm day. 102⁰ F. Mostly evaporated. White substance on side of salt dish. 5:15 p.m. all pure water gone. Moist coating of salt on bottom of salt solution dish. 6:10 p.m. both completely evaporated.
a.
Complete the experiment
b.
Analyze the results
c.
Identify the question
d.
State the hypothesis
e.
Evaluate the experiment
f.
Formulate a conclusion
g.
Design an experiment