Science Worksheet · Grades 5–7
Salt Water Worksheet
A printable science worksheet for grades 5-7 on why the ocean is salty. Students read a one-page passage on sea salt’s chemistry, the saltiest and least salty places in the ocean, how Earth’s first fresh-water ocean turned salty, and how sediment and subduction keep salinity in balance, then answer four multiple-choice questions, six true-or-false statements, and six fill-ins. A complete answer key is included.
Free with a free account — no card needed.
Subject
Science
Grades
Grades 5–7
Skill Focus
Salt Water, earth science
Lesson Length
40 minutes
Learning Objective
Students will explain what makes ocean water salty, where that salt comes from, and how it stays in a long-term balance.
Lesson Overview
About this worksheet
This worksheet traces ocean salt from simple chemistry — one atom of sodium bonded to one atom of chlorine — through where that salt actually came from and how it has stayed in balance for an enormous stretch of Earth’s history. Students learn sea salt’s fuller mineral mix (sulfate, magnesium, calcium, potassium, bicarbonate), where the saltiest and least salty water in the world is found, and why polar water is not actually the least salty of all despite melting ice.
One point is worth being precise about: rock pulled down at a subduction zone melts into the mantle, the hot rock layer beneath Earth’s crust that feeds volcanic activity — not the planet’s much deeper core, which is a separate structure entirely. It’s an easy pair of words to mix up, and the worksheet builds a true-or-false item specifically around the distinction.
The polar-ocean question makes a good discussion starter on its own: students might reasonably guess that melting ice would leave the polar oceans the least salty water on Earth, but their salinity actually sits closer to the middle of the range. It’s a useful reminder that intuition and measurement don’t always agree.
Page 2 asks sixteen questions in three forms; page 3 is a complete answer key.
How to Use This Lesson
Read the passage on page 1.
Answer the four multiple-choice questions in Section A.
Mark each Section B statement TRUE or FALSE, and be ready to say why.
Write the missing word in each Section C sentence.
Use the answer key on page 3 for self-check or grading.
Discuss why the ocean does not keep getting saltier even though salt is constantly being added to it.
Printable Resource
A classroom-ready PDF with everything in one printable resource.
Free Member Resource · Printable PDF · 3 pages · Answer Key
Salt Water Worksheet
A printable science worksheet for grades 5-7 on why the ocean is salty. Students read a one-page passage on sea salt’s chemistry, the saltiest and least salty places in the ocean, how Earth’s first fresh-water ocean turned salty, and how sediment and subduction keep salinity in balance, then answer four multiple-choice questions, six true-or-false statements, and six fill-ins. A complete answer key is included.
Keep Exploring Science
Related Worksheets
More for Grades 5–7Acids and Bases Worksheet · Density Worksheet · Heat Transfer Worksheet · Plant and Animal Cells Worksheet · Symbiosis Worksheet · The Greenhouse Effect Worksheet