Taskforce Leader Guide Taskforce Leader Guide
Surface Tension Weekly Overview
Teacher Resource
DAY 1
Penny Pileup
The "Skin" of Water
DAY 2
Soap Sprint
Surfactant Engines
DAY 3
Liquid Art
Visualizing Panic
DAY 4
Floating Feats
Variable Testing
DAY 5
Bubble Blast
Engineering Final
Science Goals for 4th Grade
1 Identify Surface Tension as a force created by water molecules sticking together (Cohesion).
2 Explain how surfactants (soap) disrupt these bonds to create movement or break the "skin."
3 Investigate variables like temperature and solutes (salt) that weaken tension.
Day 1: Penny Pileup
Key Instruction
"The slower the drop, the higher the top!"
Focus on the dome shape . This is visible proof of surface tension. Use the soap touch at the very end as a 'magic trick' to transition into Day 2.
Day 2: Soap Sprint
Key Instruction
"High tension pulls toward low tension."
Boats move because the high surface tension in front pulls the boat while the soap-disrupted water behind can't hold on.
Day 3: Liquid Art
Key Instruction
"Visualizing the disruption."
The pepper and milk colors are just tracers. We are watching the water molecules "stampede" away from the surfactant.
Day 4: Floating Feats
Key Instruction
"Heat makes molecules move faster."
Faster molecules are harder to hold together. This is why hot water has weaker surface tension than cold water!
Day 5: Bubble Blast
The Final Challenge
Students combine everything they've learned to create a "stable" surface tension (bubbles). The challenge is balancing soap (weakens) and glycerine (stabilizes) to fight evaporation.
Management Tips
• Cleanup Crew: Assign "Sponge Captains" daily to manage water spills.
• Cold vs. Hot: Keep hot water in thermoses and only distribute when ready for Day 4.
• Soap Control: Use tiny sauce cups for soap to prevent students from dumping whole bottles.
Penny Pileup Journal Penny Pileup Journal
Tension Taskforce: Day 01
Name:
Date:
The Prediction
How many drops of water do you think a single penny can hold before it spills? Think about the "skin" of the water!
My guess: __________ drops
The Evidence
Trial Number Number of Drops Notes (What did it look like?) 1 2 3
Side-View Sketch
Draw what the water looks like on the penny right before it spills.
Inspector's Eye
Did the water look flat, or did it form a dome shape? Describe why you think it stayed on the penny even when it was taller than the edge.
The Soap Sabotage
Try putting a tiny drop of soap on your finger and touching the water dome. What happened?
Soap Sprint Slides Tension Taskforce: Day 02
Soap Sprint
Using "Chemical Engines" to Race Across the Water
The Saboteur
"What happened when we touched the penny dome with soap?"
Soap is a surfactant . It breaks the "sticky" bonds between water molecules.
When the surface tension breaks, the water molecules pull away from the soap... and they take everything with them!
Visual: Breaking the Bonds
How It Works
1
The Launch
Water molecules pull toward each other in every direction.
2
The Spark
Soap is added behind the boat. It breaks the surface tension there.
3
The Thrust
The high tension in front of the boat pulls it forward!
Mission Brief
The Objective
Build a lightweight boat that can travel the furthest across the tub using only a single drop of soap.
Materials
• Foam or heavy cardstock
• Scissors
• Toothpicks
• Dish soap
Design Your Hull
Speed Secret
"Clean water is key!"
The Problem
Once the water is full of soap, the surface tension is already broken. Your engine won't work!
The Fix
You must empty your tub and fill it with fresh, cold water for every single race.
Soap Sprint Blueprints Soap Sprint Blueprints
Tension Taskforce: Day 02
Name:
Team:
Hull Design
Sketch your boat design below. Remember to include a notched engine at the back where the soap will go!
Sea Trials
Prototype 1
Observations
Distance:
Prototype 2 (Mod)
Changes Made
Distance:
The Science Secret
Why does the boat move forward when the soap hits the water behind it? Hint: Think about the molecules playing tug-of-war .
Liquid Art Instructions Liquid Art Guide
The Art of Disruption
Mission: Day 03
Experiment 1: Pepper Panic
Ingredients
• Shallow bowl of water
• Black pepper
• 1 toothpick
• Dish soap (The Saboteur)
The Procedure
1 Sprinkle a thick layer of pepper across the top of the water. Notice how it floats!
2 Dip the dry toothpick into the center. Does anything happen?
3 Now, dip the toothpick in a tiny bit of soap and touch the center again.
Experiment 2: Magic Milk
Ingredients
• Whole milk (full fat works best!)
• Food coloring (3-4 colors)
• Cotton swabs
• Dish soap
The Procedure
1 Pour milk into a shallow plate until the bottom is covered.
2 Place drops of food coloring in the center, close together but not touching.
3 Dip the cotton swab in soap, then press it firmly into the center of the colors for 10 seconds.
What's the Art Secret?
The soap (the surfactant) breaks the surface tension of the liquid. As the surface tension drops, the liquid molecules rush to the edges where the tension is still high, carrying the pepper or food coloring with them!
Liquid Art Gallery Journal Liquid Art Gallery
Tension Taskforce: Day 03
Artist:
Observation: Pepper Panic
Sketch: After Soap Touch
The Escape
Why did the pepper move so fast? Use the words tension and pull in your answer.
Observation: Magic Milk
Color your observation! What did the patterns look like when you held the soap swab in the milk?
The Tension Connection
In both experiments, the soap caused a "stampede." Describe how the surface tension molecules acted like a stretched rubber band that suddenly snapped.
Floating Feats Lab Report Floating Feats Lab
Tension Taskforce: Day 04
Investigator:
Variable Testing
The Mission
Can you float a metal paperclip on top of water? It's denser than water, so it should sink. But with enough surface tension , it can rest on the "skin" of the water. Today, we test what makes that skin break!
Test A: Temperature
Ice Cold Water
Result:
Floats
Sinks
Very Hot Water
Result:
Floats
Sinks
Test B: The Salt Saboteur
Slowly stir salt into your water. Try floating the paperclip after 1 spoonful, 2 spoons, and 3 spoons.
Amount of Salt Floats? (Yes/No) Observations 1 Spoonful 2 Spoonfuls 3 Spoonfuls
The Verdict
Based on your experiments, what two things make surface tension weaker ?
Bubble Blast Recipes Bubble Blast Recipes
Tension Taskforce: Day 05
Final Challenge
What is a bubble?
A bubble is just a thin sandwich: a layer of water trapped between two layers of soap molecules! Surface tension tries to pull the water into a tight ball, which is why bubbles are always round.
Option A
The Basic Batch
Ingredients
1 Cup Water
2 Tablespoons Dish Soap
Expectation:
Fast and easy, but bubbles might pop quickly!
Option B
Super Strength
Ingredients
1 Cup Water
2 Tablespoons Dish Soap
1 Teaspoon Glycerine
The Stabilizer Secret:
Glycerine slows down evaporation, making the bubble "skin" last longer!
Taskforce Chemist Guide
Step 1
Pour your water into the container first. Never start with the soap!
Step 2
Add soap and glycerine. Stir GENTLY . If you make foam, the bubbles won't work!
Step 3
Let it sit for 5 minutes. This lets the molecules get organized.
Bubble Engineering Log Bubble Engineering Log
Tension Taskforce: Day 05
Engineer:
Wand Blueprint
You have pipe cleaners and string. Sketch a wand design that will hold a large film of bubble solution.
Top Secret Design
Performance Review
Solution A (Basic)
Bubble Size
Bubble Strength
Solution B (Super)
Bubble Size
Bubble Strength
Final Report: Taskforce Commander
This week, we investigated Surface Tension . In your own words, what is one way to make surface tension STRONGER, and one way to make it WEAKER?
Stronger:
Weaker:
