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Simple Salinity Lab. Marine Biology Mr. Robinson. Materials. 4 test tubes 4 pipettes (droppers may be used) Red food coloring Blue food coloring Green food coloring 4 beakers Sea salt Test tube holder Tap water as required Salt water (prepared by teacher)
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Simple Salinity Lab Marine Biology Mr. Robinson
Materials • 4 test tubes • 4 pipettes (droppers may be used) • Red food coloring • Blue food coloring • Green food coloring • 4 beakers • Sea salt • Test tube holder • Tap water as required • Salt water (prepared by teacher) • 3 Erlenmeyer flasks for mixing liquids (Teacher use only)
Observation #1 • What happens when the food coloring is dropped into the regular tap water? • What does this observation tell you about the density of the food coloring when compared to the tap water? • When you check back later how much diffusion has taken place?
Observation #2 • What happens when the food coloring is dropped into the salty water? • What does this observation tell you about the density of the food coloring when compared to the salty water? • When you check back later, how much diffusion has taken place?
Part One • Fill the test tube ½ full with clear tap water • Fill the transfer pipette with green very salty water • Carefully place some very salty water into the beaker with the tap water and record your observations.
Part Two • Fill the test tube ½ full with clear salt water • Fill another transfer pipette with blue tap water • Carefully place some blue tap water into the test tube with the clear salt water and record your observations.
Part Three - A • Fill the test tube ½ full with very salty green water • Using a pipette, carefully place clear tap water into ¼ of the test tube on top of the very salty green water and record your observations. • Without emptying the test tube, continue to Three – B…
Part Three - B • Making sure that your pipette is clean, fill the pipette with slightly salty red water • Carefully place the pipette INTO the layer of very salty green water and squeeze out a drop of slightly salty red water. Record your observations. • Place your thumb on top of the test tube and shake it. Record your observations.
Part Four • See if you can make a three or four layer column of water in your test tube. • Explain how you decided the order in which to put the different salinities into the test tube? • Record your observations.