Hydro-Log Student Worksheet Hydro-Log
WATER CYCLE & SALINITY INVESTIGATION
Name:
Date:
Warm-Up: The Glass of Tea
Imagine a cold glass of iced tea on a hot, humid afternoon. Water droplets form on the outside.
Where did the water on the outside of the glass come from? (Explain your reasoning)
Video Investigation
Focus Question:
What happens to the minerals and salt when water evaporates from the ocean? Why does this matter for the ocean's taste?
The Salty Ocean Lab
Pre-Evaporation Observation
Describe the mixture of salt and water in your dish.
Post-Evaporation Results
What remains in the dish after the heat lamp/hair dryer process?
The Hydrologic Cycle Diagram
Precipitation Condensation Evaporation Runoff Transpiration
CREATE YOUR DIAGRAM HERE
Exit Ticket
"Oceans are the last stop for liquid water on Earth. The only way to get out of there is through evaporation, and that leaves all your minerals behind." — Hank Green
In your own words, why is the ocean's role as a "last stop" the reason it is salty?
The Great Recycler Slides The Great Recycler
Exploring the Hydrologic Cycle & Ocean Salinity
Warm-Up Challenge
"The Glass of Tea"
Look at the water droplets on this cold glass.
Did the water come from inside the glass or the air around it?
Watching: The Water Cycle
Embedded media
Focus Question
What happens to the minerals and salt when water evaporates from the ocean?
Pay close attention around the 3:50 mark!
Phase Changes
EVAPORATION
Liquid → Gas
Driven by energy from the sun.
CONDENSATION
Gas → Liquid
Forms clouds and dew on your tea glass.
The "Bonus" Changes
Sublimation
Solid → Gas
Deposition
Gas → Solid
Why is the Ocean Salty?
1
Runoff: Rain water erodes minerals like salt from rocks and soil.
2
The Last Stop: Rivers carry this salt into the ocean reservoir.
3
Evaporation: Pure water evaporates into the air, but the salt stays behind.
"Keep this up for a few billion years... and that's your recipe for a billion cubic kilometers of brine."
Salty Ocean Lab
Step 1: Mix
Stir 1 spoonful of salt into your shallow dish of water until dissolved.
Step 2: Heat
Place your dish under the "Sun" (heat lamp or hair dryer).
Step 3: Sketch
While you wait, complete your Hydro-Log Diagram labeling all 5 key terms.
Final Thought
"Oceans are literally the last stop for all the liquid water on Earth."
Complete your Exit Ticket on the back of your Hydro-Log.
Ocean Salts Teacher Guide Ocean Salts Teacher Guide
LESSON FACILITATION & KEY
Learning Objective
Students will be able to diagram the water cycle (Precipitation, Condensation, Evaporation, Runoff, Transpiration) and explain why oceans are salty due to the process of mineral accumulation and evaporation.
Materials Required
Hydro-Log Worksheets
Shallow dishes/Petri dishes
Table salt & Water
Heat lamps or Hair dryers
Coloring pencils for diagrams
Pacing & Facilitation
5 MIN
Warm-Up: Glass of Tea
Display Slide 2. Don't reveal the answer immediately. Encourage students to think about where the water vapor in the "humid air" goes when it hits a cold surface.
Teacher Moment: Remind them that air is a mixture of gases, including water vapor (invisible gas).
10 MIN
Video & Discussion
Watch [0:00-5:12] of the Crash Course video. Pause at [3:50] to discuss the "billion cubic kilometers of brine."
Answer: Salt stays behind because only H2O molecules gain enough kinetic energy to turn into gas. Minerals are too heavy/have different boiling points.
25 MIN
The Salty Ocean Lab & Diagramming
Direct students to start the evaporation process. While heating, they work on the diagram. If using hair dryers, monitor for splashing.
Safety Tip: Ensure heat lamps are placed at a safe distance (6-8 inches) from plastic dishes to prevent melting.
Hydro-Log Answer Key
Warm-Up
The water came from the air. Water vapor (gas) in the warm air cooled down when it touched the cold glass, turning back into liquid water (condensation).
Video Focus Question
Minerals and salt are left behind. Water evaporates as pure vapor, but the minerals are not carried into the atmosphere. This concentrates the salt in the ocean over billions of years.
Vocabulary Check
Transpiration: Plants "sweating" water vapor through leaves.Runoff: Gravity pulling water to the lowest point (ocean).Sublimation: Ice directly to gas (skipping liquid).
Diagram Guidelines
Check for:
Sun (Energy Source)
Arrows going UP (Evaporation & Transpiration)
Clouds/Cooling (Condensation)
Rain/Arrows DOWN (Precipitation)
Water moving across land (Runoff)
Ocean reservoir (The "Last Stop")
