Title
Activity: Parts Per Thousand
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
NGSS Disciplinary Core Ideas
Table of Contents
Materials
- Table 2.5
- Fig. 2.20
- Colored pencils
Procedure
The 1,000 squares in Fig. 2.20 represent 1,000 g of seawater. The table is 40 by 25 squares. Each square represents 1 g.
- Devise a way to color-code each of the following categories of seawater. Make a key at the bottom of Fig. 2.20 to explain your color code.
- Water elements (H and O)
- Major elements
- Minor elements
- Trace elements.
- Use Table 2.5 to determine the total number of grams of each of the following categories of elements in 1,000 g of seawater. Color the number of squares corresponding to this concentration in Fig. 2.20.
- Water elements (H and O)
- Major elements
- Minor elements
- Trace elements
- Compare your completed Fig. 2.20 to your classmates’.
Activity Questions
- How did you choose to color-code your table? Why did you choose these colors?
- When comparing your data to that of other students, did your color-coding system matter?
- Use as many matter terms as you can to describe seawater (e.g. solid, liquid, gas, element, compound, mixture, solution, solvent, solute, concentration).
- Why are hydrogen (H) and oxygen (O) given their own category as elements in seawater?
- The average concentration of sodium chloride (NaCl) in seawater is 35 ppt. State this same concentration in parts per hundred (percent or %).
- Why do you think marine scientists use parts per thousand (ppt or ‰) rather than parts per hundred (percent or %) to express concentrations of dissolved materials in seawater?
