In our experiment that will compare how long it will take for 100 ml distilled water to evaporate from a 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.

Question

What would a good hypothesis be?

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.

It took a total of 31hrs. 15 min. to evaporate the pure water and 32hrs. 10 min for the salt water.

We poured the water into each 5" dish and set the containers on a table. We noted the time: 8:00 a.m. Saturday.

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.

Answer 1

Based on your experiment and the observations you've noted, here is a refined hypothesis:

Hypothesis: The evaporation rate of distilled water will be faster than that of a saltwater solution due to the presence of salt, which increases the solution's boiling point and reduces the effective surface area for evaporation, thereby hindering the rate at which water molecules escape into the air.

This hypothesis is based on the assumption that the dissolved salt affects the physical properties of the water, particularly its vapor pressure, which in turn impacts the rate of evaporation. Your observations and reasoning regarding the salt potentially blocking air flow and affecting the moisture release are also well-founded and align with this hypothesis.

In your experiment, the findings show that 100 ml of distilled water took 31 hours and 15 minutes to evaporate, while the saltwater solution took 32 hours and 10 minutes. This data partially supports your hypothesis but also indicates that the difference in evaporation times was small, suggesting other factors could also be influencing the results, such as environmental conditions or the type of container used. Further investigation may be warranted to explore these variables more thoroughly.