🌊 The Ripple Effect

Earth Science — Investigation Prep

How does water shape the surface of New York State?

Today's Mission

We are getting ready to run a real investigation about water.

By the end of class you will be able to:

  • Tell an independent variable from a dependent one
  • Write a prediction scientists would accept
  • Use the words: erosion, deposition, permeability, porosity, infiltration, runoff, weathering
  • Build a data table that earns full credit
  • Recognize what a strong claim looks like

You will not touch any materials today. Today is about thinking like an investigator so next class goes smoothly.

Two Places, One Force

The Genesee River
Carves banks, carries sediment, builds new land downstream near Rochester.

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A NYC Rain Garden
Soaks up stormwater, slows runoff, sends clean water into the ground.

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Turn & Talk: Both are shaped by water. How can the same substance do two such different jobs?

Part 1 — The Words That Drive the Lab

Vocabulary you'll use all week

Erosion & Deposition

Erosion — water removes and carries away sediment/rock (a destructive process).

Deposition — water drops off sediment in a new place (a constructive process).

Misconception alert: These are not opposites that happen separately. On a river bend, erosion (cut bank) and deposition (point bar) happen at the same time.

Permeability & Porosity

Porosity — how much empty space is between particles (the room available for water).

Permeability — how easily water can move through the connected spaces.

Big particles (gravel) → high porosity and high permeability → water drains fast.
Tiny, tightly-packed particles → water moves slowly.

These are not the same word! Porosity = how much space. Permeability = how connected the spaces are.

Infiltration, Runoff & Retention

Infiltration — water soaking down into the ground.

Runoff — water flowing across the surface (didn't soak in).

Retention — water held/stored within the material.

Why it matters: A good rain garden maximizes infiltration and retention and minimizes runoff — keeping stormwater out of the sewer system.

Weathering: Two Flavors

Mechanical (Physical)

Rock is broken apart physically — no change in composition.
Example: water freezes in a crack, expands, splits the rock.

Chemical

Rock is dissolved or changed at the mineral level.
Example: acidic water dissolves limestone → caves, sinkholes.

In Investigation C, vinegar (acid rain) on chalk (limestone) models chemical weathering. Watch for bubbling — that's the reaction.

Part 2 — Designing a Fair Test

Independent vs. dependent variables, and controls

The Three Kinds of Variables

Independent Variable (IV) — what YOU change on purpose.

Dependent Variable (DV) — what you measure to see the effect.

Controlled Variables — everything you keep the same so the test is fair.

Memory hook: I change the Independent. The result Depends on it (Dependent).

Worked Example — Stream Table

If I raise one end of the stream table higher (steeper slope), the sediment travels farther.

IV: slope (height of the table)
DV: distance sediment / figurine moves
Controls: same amount of water, same sediment type, same pour rate

Why 3 trials?
One run could be a fluke. Three trials + an average make the data trustworthy.

Your Turn — Variable Sort

For each scenario, whiteboard the IV, DV, and one control:

  1. Pour more water on the same sand pile.
  2. Compare gravel vs. fine sand in a rain-garden bottle.
  3. Cover the slope with a washcloth (plants) vs. bare sand.
  4. Soak chalk in vinegar vs. tap water.

Be ready to defend why each variable goes where it does.

Part 3 — Predictions & Data Tables

Writing what the rubric rewards

What Makes a Prediction "Proficient"?

❌ Weak

"The chalk will get smaller."

No variables, no reasoning.

✅ Strong

"If the chalk sits in vinegar (acid), then it will lose more mass than in water, because acid chemically dissolves limestone."

Formula: If [I change IV], then [DV will change this way], because [reason].

The Data Table That Earns Full Credit

(Title goes here — name your DV & IV) Trial 1 Trial 2 Trial 3 Average Observations
IV value A
IV value B

Every full-credit table needs: a title, the IV and DV labeled with units, three trials, an average, and an observations column.

Quick Check

In the chalk-weathering table, what are the units?

Mass is measured in grams (g). Change = Final − Initial. If the chalk lost mass, the change is a negative number — and you must write it that way.

Part 4 — Your Three Investigations

Preview the options

Option A — Stream Table 🏞️

Models: a river like the Genesee — erosion & deposition.

You might change (IV):

  • slope
  • amount of water
  • sediment type
  • surface cover (bare / washcloth / acetate)

You'd measure (DV):

  • distance sediment or figurines move
  • amount of sediment moved

Answers focus questions: How is Earth's surface changed by erosion & deposition?

Option B — Rain Garden 🌧️

Models: NYC green infrastructure — permeability, infiltration, runoff, retention.

You might change (IV):

  • type of sediment/material
  • layering of materials

You'd measure (DV):

  • infiltration rate
  • amount of runoff
  • water retained

Answers focus questions: Which materials make the most effective rain garden?

Investigation C — Weathering 🧪

Everyone does this one. Models chemical weathering of NY limestone.

Setup:

  • Chalk = limestone
  • Tap water = normal rain
  • Vinegar = acid rain
  • Mass before & after 5 min

IV: type of liquid
DV: change in chalk mass (g)
Controls: time, chalk size, liquid amount

Goggles required. Use tweezers for chalk. Never taste anything.

Part 5 — Claims & the Big Ideas

CER, feedbacks, and scale

Claim · Evidence · Reasoning

Claim — your answer to the question.

Evidence — the numerical data that backs it up.

Reasoning — the science that connects evidence to claim.

Example: Claim: Vinegar weathers chalk more. Evidence: chalk lost 0.4 g in vinegar vs. 0.0 g in water. Reasoning: acid chemically dissolves the calcite in limestone.

A claim with no numbers drops you down the rubric. Always cite your data.

Feedbacks: Systems That Respond

A feedback is when a change in one part of a system causes further change — either amplifying it or stabilizing it.

Example for Session 2: A rain garden adds plants → plants absorb water → less runoff during storms. The change (more vegetation) feeds back to change the urban water system.

Spatial & Temporal Scale

Spatial = how much area / how big.

Genesee River: shapes land along its whole ~250 km length.
Allegheny caves: form in small, localized spots.

Temporal = how fast / how long.

River flooding: changes land quickly.
Cave dissolution: takes a very long time.

Bonus Brain-Stretch: Water & Melting Rock

Water doesn't only shape Earth's surface. Deep underground, water lowers the melting point of mantle rock.

Session 2, Q9: Two rocks at the same depth & pressure — one wet, one dry. The wet rock melts at a lower temperature, so it can be liquid while the dry rock is still solid.

Counter-intuitive but key: adding water lowers the melting point — it does not raise it.

How You'll Be Scored

Level What it means
Excelling Exceeds the expectation — precise, complete, extra detail
Proficient Meets it — correct and complete
Developing Partially there — some pieces missing or off
Emerging Minimal or incorrect

The biggest scoring category is Planning & Carrying Out Investigations — so nail your variables, prediction, procedure, and data table.

Exit Ticket 🎟️

On your own slip:

  1. Scenario: "We test how grain size affects how fast water drains through sediment."

    • What is the IV?
    • What is the DV?

  2. Define two of today's vocab words in your own words.

This tells me you're ready to plan your investigation next class.

Vocabulary Reference

Erosion — water removes & carries sediment (destructive).
Deposition — water drops sediment in a new place (constructive).
Porosity — how much empty space is between particles.
Permeability — how easily water moves through connected spaces.
Infiltration — water soaking into the ground.

Vocabulary Reference (cont.)

Runoff — water flowing across the surface.
Retention — water held/stored within material.
Mechanical weathering — rock physically broken apart.
Chemical weathering — rock dissolved/changed at the mineral level.
Feedback — a change that causes further change (amplifying or stabilizing).
Spatial scale — how much area is affected. Temporal scale — how fast/long.

UNIT OVERVIEW: This deck prepares students for the NYSED "Ripple Effect" investigation (HS-ESS2-5). It is the prep day BEFORE planning/conducting. Total time: 80 minutes. PE: HS-ESS2-5 — plan & conduct an investigation of water's properties and effects on Earth materials and surface processes. GOAL TODAY: Build vocabulary, experimental-design skill (IV/DV/controls), prediction writing, data-table structure, CER, and a preview of the three investigations + rubric. DO NOT START THE LAB TODAY — this is readiness.

TEACHER MOVE: Set the frame clearly — "prep day." Lower anxiety, raise focus on skills. TIMING: ~2 min. Part of the 0–8 hook block. TRANSITION: Move to the two photos.

TEACHER MOVE: Project alongside the Genesee photo (Student Directions p.3) and rain-garden photo (p.6). 60-sec turn-and-talk, harvest 3–4 ideas on the board. EXPECTED STUDENT RESPONSES: "Water moves stuff," "water soaks in," "speed matters," "the ground is different." KEY POINT TO SURFACE: Water's PROPERTIES (it flows, dissolves, soaks in, freezes/expands) are what make it powerful. TIMING: ~6 min. Completes the 0–8 hook block. TRANSITION: "Let's get the words we need to talk about this precisely."

PHASE GOAL: Direct-teach 8 core terms in 4 paired clusters. GROUPING: Whole class, students logging in notebooks. TIMING: ~12 min (8–20 min block). MATERIALS: Notebooks. Optional vocab word-bank card for support students.

TEACHER MOVE: Use a river-bend sketch on the board. Fast water on the outside = erosion; slow water on the inside = deposition. CONNECTION: This is exactly Q2 in Session 2 — students must describe BOTH processes. TIMING: ~3 min.

TEACHER MOVE: Hand-gesture: porosity is the size of the gaps; permeability is whether the gaps connect into a path. Clay can be porous but NOT very permeable. CONNECTION: Rain Garden (Option B) and Q4a/4b/4c hinge on these. COMMON MISCONCEPTION: Students fuse the two terms. Separate them explicitly. TIMING: ~3 min.

TEACHER MOVE: Tie to NYC green infrastructure framing from the directions. More infiltration + retention = less sewer overflow = cleaner waterways. CONNECTION: Option B's dependent variables are usually infiltration rate, runoff amount, or retention. TIMING: ~3 min.

TEACHER MOVE: Connect to NY landscapes — frost wedging in the Adirondacks (mechanical), cave/sinkhole formation in the Allegheny Plateau (chemical). CONNECTION: Q16 asks students to PREDICT the weathering type + give observational evidence (bubbling, cloudiness, mass loss). COMMON MISCONCEPTION: Bubbling means "boiling" — clarify it's a chemical reaction releasing gas. TIMING: ~3 min. TRANSITION: "Now the real skill — how scientists design a fair test."

PHASE GOAL: The most heavily-weighted rubric dimension (SEP Planning & Carrying Out Investigations) lives here. Spend real time. TIMING: ~15 min (20–35 min block).

TEACHER MOVE: Write the memory hook large. This is THE skill of the lab. COMMON MISCONCEPTION: Students label what they MEASURE as the IV. Hammer: "Did you choose to set it, or did you measure the outcome?" TIMING: ~3 min.

TEACHER MOVE: Walk through this slowly. Name each variable and WHY it's that category. KEY POINT: The "control all variables except one" rule (from the procedure) is what makes it a fair test. TIMING: ~3 min.

TEACHER MOVE: Groups of 2–3, ~5 min to work, then review each aloud. Circulate and check. ANSWER KEY: 1. IV=volume of water; DV=sediment/distance moved; control=slope, sediment type. 2. IV=sediment type/permeability; DV=infiltration rate/runoff/retention; control=amount of sediment, water volume. 3. IV=surface cover (permeability); DV=distance/amount eroded; control=slope, water amount. 4. IV=type of liquid; DV=change in chalk mass; control=time (5 min), chalk size, liquid volume. CONFERRING QUESTIONS: "Did you set that or measure it?" "What would ruin this as a fair test?" TIMING: ~8 min total. Completes 20–35 block. TRANSITION: "Once you know your variables, you write a prediction."

PHASE GOAL: Strong prediction structure + the required data-table format (a frequent point-loser). TIMING: ~13 min (35–48 min block).

TEACHER MOVE: Model the upgrade live — take the weak one and add IV/DV/reason. RUBRIC NOTE: "Excelling" = reasonable prediction of how DV changes when IV is manipulated. "Developing/Emerging" = illogical or missing reasoning. DIFFERENTIATION: Support students get the sentence frame printed on a card. TIMING: ~5 min.

TEACHER MOVE: Students sketch this empty frame in their notebooks now, so it's muscle memory next class. RUBRIC NOTE: Q7 explicitly requires title, variables, 3 trials, averaged data, observations. Missing the average is the #1 deduction. COMMON MISCONCEPTION: Recording data but never averaging it → drops from Proficient to Developing. TIMING: ~5 min.

TEACHER MOVE: Quick cold-call. Emphasize the negative-value rule (rubric explicitly checks correct positive/negative values). TIMING: ~3 min. TRANSITION: "Here are the three investigations you'll choose from."

PHASE GOAL: Tour Option A, Option B, Investigation C so students can request a preference and start thinking about variables. TIMING: ~14 min (48–62 min block).

TEACHER MOVE: Show the stream-table setup diagram (Directions p.5). Point out the ring stand, pour bottle, collection bucket. KEY POINT: This option = erosion/deposition + spatial/temporal scale + properties of water. TIMING: ~4 min.

TEACHER MOVE: Show the bottle setup diagram (Directions p.8). Note the straw/cap and the cup that catches water. KEY POINT: Effective design = controlled infiltration + high retention + low runoff into sewers. TIMING: ~4 min.

TEACHER MOVE: Show the cave/sinkhole block diagram (Directions p.11). Chalk reacting with acid = how caves form in the Allegheny Plateau. SAFETY: Restate goggles + tweezers + chalk-allergy accommodation (partner collects data). CONNECTION: Q6 and Q16/17 all come from this investigation. TIMING: ~4 min. TRANSITION: "Now — how will your answers be judged?"

PHASE GOAL: Teach CER (scored throughout) and PREVIEW the harder Session-2 concepts. Preview only — not mastery today. TIMING: ~12 min (62–74 min block).

TEACHER MOVE: This structure is scored in Q12, Q28, and all of Packet 2. Make "cite your data" the mantra. TIMING: ~4 min.

TEACHER MOVE: Preview only. Q5 asks students to name a water-cycle process change AND a feedback in the geosphere. CONNECTION: HS-ESS2-2. Keep light today; revisit at Session 2. TIMING: ~3 min.

TEACHER MOVE: Preview for Q8. Surface water acts fast over wide areas; groundwater dissolution is slow and localized. CONNECTION: HS-ESS2-1. TIMING: ~3 min.

TEACHER MOVE: Preview only for advanced readiness. Wet mantle rock (Box D) = liquid; dry (Box E) = solid at the same conditions. DIFFERENTIATION: Extension students can attempt the graph reasoning now. CONNECTION: DCI HS-ESS2.C — water lowers viscosities and melting points of rocks. TIMING: ~2 min. TRANSITION: "Let's see exactly how you'll be graded."

TEACHER MOVE: Show the actual rubric language. Reassure: there's a path to credit even if not perfect, but completeness matters. TIMING: ~3 min. Part of 74–80 block.

TEACHER MOVE: ~4 min to write, collect on the way out. Also collect Student Directions packets. ANSWER: IV = grain/particle size (permeability); DV = drainage/infiltration rate. ASSESSMENT: Correct IV/DV = on track for the dominant rubric dimension. Use misses to form support pairs next class. TIMING: ~5 min. Completes the lesson at 80 min.

Study reference. No live teaching needed.

Study reference. End of deck.