Salt Water Experiment

Sea water experiment 2

Report your results. Discuss what happened and give scientific explanations for what you observed. Based on what you know about the characteristics of water try to explain the differences between the way the salt and the fresh water froze. Describe what happened to the food coloring and explain the results. How do your results relate to our study of the oceans?

Materials: 4 glasses (8 to 12 oz.), water, salt, food coloring

Procedure:

1. Mix a saturated solution of salt water by adding several tablespoons of salt to a glass of water. Stir it and let it settle for five minutes. There should be undissolved salt on the bottom of the glass. Pour the salt water into another glass until it is 2/3 full, taking care to leave the undissolved salt in the first glass.

2. Fill the 2 remaining glasses to about 2/3 full using tap water for one and tap water with 3 or 4 drops of food coloring for the third. Make sure all three glasses are filled to the same level.

3. Place the glasses in the freezer.

4. Record observations at half hour intervals until no more changes are recorded.

Sample one :

tap water Sample 2:

Tap water with food coloring yellow food coloring Sample 3:

Salt water poured off Sample 4:saltwater with undissolved salt

Start of experiment: 0 min Room temperature water 20.56 degrees c 20.56 degrees yellow food coloring swirled in to the water and mixed Water 20.56 degrees c

Water appears cloudy Water 20.56 degrees c water is very cloudy appears to have sodium chloride undissolved at the bottom of the cup.

Observation 1:

30 min 15deg c

Water is clear with a few air bubbles 15 deg c

Water is yellow no change yellow food coloring is mixed throughout 17deg c

Water is now clearer and not as cloudy as before 18 deg c

Water is still slightly cloudy and has undissolved ay the bottom of the cup.

Observation 2:

60 min -3deg c

Ice crystals beginning to form on top and down sides of glass -3deg c

Ice crystal starting to form on the top of the cup. Some of the yellow food coloring appears to be separating and collecting on the bottom of the cup. 0 deg c

Water appears unchanged beside temp 4 deg c

Water appears to have cleared and is no longer cloudy. No ice crystals formed. Salt is still undissolved at the bottom of the cup

Observation 3:

90 min -3 deg c

Aprox ¼ inch ice buildup on the top of the water. -3 deg c

Approx. ¼ inch ice built up on top and down the side of the cup. A small amount of yellow food coloring has collected in a swirl pattern on the bottom of the cup -5 deg c

Water has no ice crystals forming that are visible from eye view. -4 deg c

Water has no ice crystals forming that are visible, there is visible undissolved salt on the bottom of the cup and the water has become clear, several air bubbles are formed on the side of the cup

Observation 4:

120 min Temp unable to perform sample is frozen there Is a small amount of unfrozen water inside the sample in the middle, this sample froze from the outside to the middle Temp unable to perform as the sample is frozen, there is a small amount of unfrozen water inside the water sample in the middle. Temp -5 deg c

This sample has now formed crystals, but they are forming in thin sheets, and freezing from the bottom to the top. The crystals are not solid and move around.

Temp -7 deg c

This sample is just now starting to freeze. The undissolved salt on the bottom of the cup is now solid. The thermometer cannot push through it, and a small amount of ice crystals are in the water.

Observation 5:

150 min Frozen solid point of no change noted Frozen solid point