Interactive Salinity, Temperature, Density Lab (6) (2) (1)
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Pasco-Hernando State College *
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Course
2001
Subject
Geology
Date
Apr 3, 2024
Type
docx
Pages
4
Uploaded by ElderScience8563
Salinity/Temperature/Density Lab
This lab is designed to investigate the relationship between salinity, temperature and density. Salinity is a measure of dissolved solids in the ocean water. Density is the mass per unit volume of a substance. Materials needed:
Block of wood
Liquid food coloring: (Red, Blue, Yellow)
Clear plastic shoe box or clear dish (Half filled with water that has been at room temperature for 1 hour).
150 ml (about 2/3 cup) of water with 1 Tablespoon salt and 4 drops of red food coloring.
Mix the food coloring and salt in the water before you start.
150 ml (about 2/3 cup) of cold water with 4 drops of blue food coloring mixed into the water.
150 ml (about 2/3 cup) of hot tap water with yellow food coloring mixed into the water.
Camera or cell phone (When you finish you will take a picture that you will send to your instructor.) Procedure:
1.
Place one edge of the clear plastic shoe box that is half filled with room temperature water on the wooden block. See Figure 1 below and note that the picture does show the yellow water with the same condition as your experiment. You will start with red water that has dissolved salt. Do not add or prepare the three water solutions yet. 2.
Place something white under and the side of your container.
3.
The following solutions will be added to the clear water. (Be sure to read step 4 before adding the solutions.)
a.
Hot yellow water slowly added to the water in the plastic box
b.
Salty red water slowly added to the water in the plastic box.
c.
Cold blue water slowly added to the water in the plastic box.
4.
Watch from the side of the container as you complete the following:
Figure 1 Example for Salinity, Temperature and Density Lab
a.
Slowly add the hot yellow water to the water in the plastic box. Pour from one side of the container (see diagram above). Record your observations. Once the water stops moving proceed to step 4b.
b.
Slowly add the salty red water to the water in the plastic box. Record your observations. Allow the solutions to stop moving and then proceed to 4c.
c.
Slowly add the cold blue water to the water in the plastic box. Record your observations. 5.
Take a picture from the side of your experiment and email or attach it to your assignment. (Be sure to place your name on the email and assignment.)
6.
Explain the results of the experiment on your Lab Data Sheet.
7.
Send the completed Lab Data Sheet to your instructor at myPHSC. Figure 2. Picture of a similar experiment but with different water conditions.
Salinity Lab Data Sheet
Name Andrea Maras
Observations:
a.
What happened to the hot yellow water
that was slowly added to the water in the plastic box? The food coloring stayed in the front of the container while the rest spread downward. Also, the yellow color was lighter on the top layer. The heat caused the water molecules to gain energy and
spread out, in other words increasing the volume and decreasing the density.
b.
What happened to the salty red water
that was added to the water in the plastic box? This was my favorite color to watch, adding the salt to the mixture made the water heavier so it mixed evenly with the yellow water which made a bright orange color. I also noticed that even though it spread out there was a dense layer at the bottom of the
container which was of a darker color which is called density stratification.
c.
What happened to the cold blue water
that was added to the water in the plastic box?
When adding the cold blue slowly it sank to the bottom due to cold water being denser than room temp water. I also noticed how the blue water remained on the top and there was a layer in the corner mixed of yellow/red that didn’t mix with the blue.
Explain your results:
a.
Why did the hot yellow water
end up in its location?
It ended up at the top of the container because it was less dense than the surrounding room temp. When hot water is added to cooler water it rises to the top because it expands which makes the color lighter. Also, the heat causes the water molecules to spread out which makes hot water less dense.
b.
Why did the salty red water
end up in its location? The salty red water ended up in the bottom of the container because it was denser. When adding salt, it must dissolve which
makes it denser and sinks due to its high density. Also, with the density difference it
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causes the salty red water to settle to the bottom of the container forming a different layer.
c.
Why did the cold blue water
end up in its location
? Cold water is denser than warm water because its molecules are closer together. When the denser cold water was added to the container with the room temperature water it sank to the bottom due to gravity. Which is why there was a different layer towards the bottom of the container of the blue and red/yellow mixture.
d.
Picture of your experimental results: My final pic is attached. This was a super cool experiment!