00:00

TA Focus

Cold Call

Team Scoreboard

MC
Messages · Dr M. Calder now
Today's the day! 🌊📋
Site Packs sent to your team. 3 sites on the Tees. Get me averages + a one-line conclusion. Final scoreboard tonight.

Lesson 19 — PGFI

Fieldwork Day 🌊

"What does the river actually do downstream?"

📊
→
🔍
→
🎯

Calculate · Spot the anomaly · Conclude

PGFI Obj 4 evidence by the end · 50 minutes

FAB 4 · Arrival

FAB 4 Arrival – Recall from L17/L18

Whiteboards. 4 minutes. Q4 leads into today.

1. Recall — L18

Name the 3 sampling strategies.

Random · Systematic · Stratified.

2. Recall — L18

Why is "be careful" a bad control?

It doesn't say what you'll DO. A control names a specific action (wellies, buddy, stay back, etc).

3. Recall — L17

How do you measure velocity?

Mark 10 m, drop a float, time it, repeat 3 times, average. Velocity = distance ÷ time.

4. Lead-in 🔬

You've got 5 depth readings at one site: 0.42, 0.45, 0.43, 1.20, 0.41 metres. Spot anything weird?

1.20 m — way bigger than the others. Could be: a deep hole, a mistake, a misread. Today: how to handle that.

Starter

When data goes weird

3 problems. Each gets fixed at a different moment. Tap to reveal.

BEFORE
📐
No units. "Width = 12. Depth = 0.5."
Fix before the trip — print column headers (m / m/s / cm) so you can't forget.
ON THE DAY
📋
Missed reading. "We just remember it was about half a metre."
Fix on the day — always re-check the sheet before leaving each site.
WRITE-UP
⚠️
Anomaly. "4 readings are 0.4 m. One is 1.2 m."
Fix in write-up — highlight it, justify it, average without it. Never delete.
I Do · 1 of 2

📍 Site A — upstream

Raw data on the left → averages on the right.

📋 Raw data

Width2.4 m
Depths (×5)0.18 · 0.22 · 0.25 · 0.21 · 0.19
Velocity times18s · 19s · 17s
Pebbles (×10)8.2 · 9.1 · 7.8 · 10.4 · 8.5 · 9.0 · 7.5 · 8.8 · 9.3 · 8.9
→

🧮 Averages

Width2.40 m
Avg depth0.21 m
Velocity = 10 ÷ 180.56 m/s
Avg pebble8.75 cm

✓ Sense check: shallow, slow, chunky pebbles — yes, upstream.

💡 Sum first, divide last. Round to 2 d.p.

We Do · 1

📍 Site B — and there's an anomaly

Spot the odd value first. Class agrees on each blank, then we type it in.

📋 Raw data — Site B

Width5.8 m
Depths (×5)0.42 · 0.45 · 0.43 · 0.41 m
⚠️1.20 m — this 5th reading is way bigger than the others
Velocity times11s · 12s · 11s
Pebbles (×10)4.1 · 3.8 · 4.5 · 3.9 · 4.2 · 3.7 · 4.4 · 4.0 · 3.6 · 4.3

Avg depth (4 valid) = m  |  Avg time = s →  Velocity = m/s  |  Avg pebble = cm.

💡 Answers: 0.43 m · 11.3 s · 0.88 m/s · 4.05 cm

I Do · 2 of 2

3 things to do with an anomaly

In order. Tap each card.

🔍

1. Spot it

2× or 3× the others

Look at the pattern. The 1.20 next to four 0.4s is obvious.

📝

2. Highlight + justify

never delete it

Why? Deep hole · misread · stick hit soft patch.

Deleting = data tampering.

🧮

3. Average without it

divide by N–1

(0.42 + 0.45 + 0.43 + 0.41) ÷ 4 = 0.43 m

✓ Honest scientists win more credit than "perfect" data scientists.

We Do · 2

Read the Trend

Each line shows how a variable changed Site A → B → C. Match data on the left to the conclusion on the right.

Site A Site B Site C value width ↑ depth ↑ velocity ↑ pebble ↓

Score: 0/6

Data trend (Site A → C)

Width: 2.4 → 5.8 → 8.9 m   (↑)
Avg depth: 0.21 → 0.43 → 0.62 m   (↑)
Velocity: 0.56 → 0.88 → 1.05 m/s   (↑)
Avg pebble: 8.75 → 4.05 → 1.85 cm   (↓)
One Site B depth = 1.20 m, others ≈ 0.43 m
L17 hypothesis: width↑, depth↑, velocity↑, pebble↓

What it tells us

River speeds up downstream — more water, less friction with banks.
All four trends match the prediction — the data supports the hypothesis.
Channel gets wider — tributaries are adding water as we go downstream.
Anomaly — exclude from average, justify (deep hole?), keep visible in raw data.
Channel cuts deeper as flow grows — more erosion of the bed.
Pebbles get smaller — worn down by erosion as they travel downstream.
👆 Click a trend on the left, then the conclusion on the right.
We Do · 3

Spot the 3 Mistakes

A pupil wrote this results paragraph for Site B. 3 things are wrong. Click the phrases you think are wrong.
1
2
3
Site B depths were 0.42, 0.45, 0.43, 1.20, 0.41 metres. I deleted the 1.20 because it was wrong, then averaged the other four to get 0.43 m. Velocity was 10 m ÷ 11.3 s = 0.88 m/s. Average pebble size was 4.05. Comparing to Site A: depth and velocity have both increased downstream, which disproves the L17 hypothesis.
✅ Correct version: "Site B depths were 0.42, 0.45, 0.43, 1.20 (anomaly — possible deep hole, excluded), 0.41 m. Average of the four valid readings = 0.43 m. Velocity = 0.88 m/s. Avg pebble = 4.05 cm. Compared to Site A, depth and velocity have increased — this supports the L17 hypothesis."
Team Task · 8 min

📋 Site Pack — 8 minutes

One printed Site Pack per team. Photo it at the end = PGFI Obj 4 evidence.

📊 1
Calculate
Averages for Sites A, B, C.
🔍 2
Anomaly
Spot it. Highlight it. Justify in 1 line.
🎯 3
★ Conclusion
1 line. Link to L17 hypothesis.
Sample conclusion: "As the Tees flows downstream, width, depth and velocity all increased while pebble size decreased. This supports our hypothesis."
🏆 Final Buzzer · 6 Qs

🏆 Final Buzzer — Last One!

6 questions to settle the whole series. Score is cumulative L16 → L19. First to BUZZ answers.
QUESTION 1 / 6
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Click a team's BUZZ button to claim the question.