Salinity Calculations1. Finding salinity (% & ppt)2. Converting from % to ppt3. Finding amount of salt in saltwater4. Making water with specific salinity

• To find o/o, divide the part by the whole, then multiply by 100.

• To find o/oo, divide the part by the whole, then multiply by 1000.

– If 38 out of 50 students passed a test, what percent passed? How many parts per thousand passed?

– 7.0 lbs of saltwater contains of 1.5 lbs of salt. What is the salinity in percent & parts per thousand?

1. Finding % and ppt (o/oo)

2. Conversions between % and o/oo• To go from % to o/oo, multiply by 10 (or move decimal one to right)

• To go from o/oo to %, divide by 10 (or move decimal one to left)

1.1.3 % = _____ o/oo

2.0.265 % = _____ o/oo

3.2.77 % = _____ o/oo

4.7.00 o/oo= _____%

5.6.55 o/oo= _____%

6.55 o/oo= _____%

3. Finding amount of salt in water– Using %

• Multiply weight by % over 100

– Using o/oo • Multiply weight by o/oo over1000

– On average, ocean water has a salinity of 3.5%. How many lbs of salt would there be in 60 lbs of ocean water?

– If a 250 lb sample of salt water has a salinity of 45 o/oo, how many pounds of salt are dissolved in it?

Making Water with certain salinity– Find out how much of the water is salt (as in previous slide).

That is how much salt you need.– Subtract the amount of salt from the amount of salt water to

find the amount of water you need.– Make 25.0 grams of salt water with a salinity of 45 ppt.

Today you are going to… complete the salinity lab.

So you can… calculate salinity problems and understand the effect salinity has on density and organisms.

You’ll know you’ve got it when…you can • Create 3 layers of water with different salinities• Answer the lab questions

Lab!• Everyone in your group has a job– Salt master – get salt, clean up– Water master – get water, clean up– Mix master – label test tube, mix water & add food coloring, clean up

• Place your finished test tube in the sand• When finished:– Clean up & return to your lab desk. I will give you a lab conduct

grade then.– Work on the Post Lab Questions

• Lab conduct will be graded throughout period

Lab Conduct

• Stay in group, at one desk• Actively contribute– One person get water whilst another gets salt

• Get low when reading graduated cylinder• Be respectful of equipment – Be careful with glassware – don’t clang it – Don’t set round things on table…they’ll roll off!

Lab Conduct

• Stay in group, at one desk• Actively contribute– One person get water whilst another gets salt

• Get low when reading graduated cylinder• Be respectful of equipment – Be careful with glassware – don’t clang it – Don’t set round things on table…they’ll roll off!

Procedure1. Mass salt

Tare cup

2. Measure water Get low!Dump water in little test tubeYou may have to use grad. Cyl. Twice

3. Dump salt in little test tube4. Cover with thumb & carefully shake to mix5. Add food coloring (not much) & swirl6. Carefully transfer to large test tube

• Supplies– 1 large test tube– 1 small test tube– 1 pipette (use to get exact amounts of water)– Empty paper cup to measure salt in

When finished– show me your layers & give me all group

members’ papers to grade layers– Rinse both test tubes out & put them upsidedown

in containers by sink– Rinse pipette & put it in your beaker. Put it by the

sink.– Dump any remaining salt into the sink & put your

paper cup there.

Salinity of Ocean Water Worksheet1. On average, ocean water is 1.19% calcium. Convert this to

ppt.

2. If there are 306 quintillion pounds of water in the ocean, how many pounds of calcium are there?

• In 1800 pounds of water of seawater, there are 20.5 pounds of salt. What is the salinity of the water? (% and o/oo)

Finding weight or mass (lbs or kg) using percent (%) or ppt (o/oo)– On average, ocean water has a salinity of 3.5%.

How many lbs of salt would there be in 60 lbs of ocean water?

– If a 250 lb sample of salt water has a salinity of 45 o/oo, how many pounds of salt are dissolved in it?

Bell Ringer 11/14/13 – 3 min

• Quietly read the “Salinity of Seawater Lab Info Sheet”.

Bell Work – 3 minutes• Take out your: – Salinity of Seawater Lab Info Sheet – Salinity of Seawater Lab.

• Work on the Salinity Lab Problems.• Must have # 3, 8-10 finished to start lab!– # 8, 9, & 10 refer to numbers 6, 4, & 3.