Unit 05 · Forces & Motion arc · 7th grade

It's all
relative.

Is the beetle fast? Compared to what — the tile, the classroom, the garden snail? Motion only makes sense against a reference point, and "fast" only makes sense with a graph. Five frames, one dash, and the slope that tells the truth.

position → velocity 6 manipulatives 12 flashcards 1 beetle
the 10-cm dash · one frame per second
t = 0 s0 cm
t = 1 s3 cm
sniff! t = 2 s4 cm
t = 3 s8 cm
t = 4 s10 cm

same beetle, same dash — uneven frames. was he fast?

The phenomenon · five frames, one question

The 10-Centimeter Dash

One frame per second, start to finish. Look at the spacing: frames 1–2 barely moved (he stopped to sniff — it's what he does), frame 3 covered four times that ground. So: was he fast?

3 cm/s frame 0 → 1 · cruising
0 cm/s frame 1 → 2 · sniff break
4 cm/s frame 2 → 3 · scurrying
2 cm/s frame 3 → 4 · cruising home

"Was he fast?" is really two questions.

On average: 10 cm in 4 s = 2.5 cm/s — one number for the whole trip. Second by second: 3, 0, 4, 2 — a different story in every frame. The average is honest but quiet; the graph remembers everything. Keep both habits for the rest of the year.

Watch · Khan Academy

The odometer's side of the story

Unit context only. This saved-caption video teaches distance and displacement. It is not exact support for the worksheet's speed, acceleration, unit-rate, or graph-segment Parts, so it is not promoted into those Learn How routes.

Read · Eleo explains

The beetle's commentary track

A motion article remains source-gated until its exact companion video and investigation hand-off are settled.

Sketch · sketchnotes

Map the journey two ways

The exact distance/displacement captions are saved. Printable sheets stay pending until the full analysis package is ready.

Distance and displacement · 4:14

Sketchnote in the works

status captions saved · analysis package pending

Investigate · evidence first

Predict the graph before it moves

The page's race, odometer, speed, and graph tools remain the working lab. A standalone print-first investigation is still in review.

MS-PS2-2 · model and measure motion

Investigation in the works

Use the existing page models now; a prediction, data, and revision record will land here when authored.

in the works

Manipulative 01 · where, compared to what?

The odometer vs. the ruler

Every position needs a reference point — a "compared to here." Walk the beetle around the track and watch two honest instruments disagree: the odometer counts every step (distance), the ruler only cares where you started and where you stand (displacement).

0odometer · distance (cm)
+0ruler · displacement (cm)
012345 678910 cm

walk around. watch the two numbers.

Manipulative 02 · distance ÷ time

The Speed Board

Average speed = total distance ÷ total time. That's the whole formula — the drama comes from the range. Pick a mover, pick a trip, and feel the difference between a snail and a sound wave.

2.8 min the beetle gets there eventually. bring a book.

Read the units like a scientist

cm/s — beetle speeds, ant speeds, classroom speeds.
m/s — the science standard. 1 m/s ≈ a relaxed walk.
km/h — road speeds. 3.6 km/h = 1 m/s exactly.
Speed is a ratio — distance per time. That's the crosscutting concept Scale, Proportion, and Quantity doing its job.

Manipulative 03 · the truth-teller

The slope remembers everything

Time on x, distance on y — the dash from the film strip, drawn as a line. The slope of that line IS the speed. Drag across the graph and read it like a scientist.

01 23 4 s 02 46 810 cm cruise · 3 sniff · 0 scurry · 4 cruise · 2

drag across the graph — read the race

steep faster speed — more ground per second
flat stopped — time passes, distance doesn't
downhill coming back toward the start

slope = rise ÷ run

Pick the scurry segment: the line rises 4 cm while time runs 1 s. 4 ÷ 1 = 4 cm/s. Do it anywhere on the graph — the slope and the speed are the same number wearing two outfits.

Manipulative 04 · match the story to the shape

Pick a race story, then file it under the graph that tells it.
steady climb one slope, no drama
fast, then flat steep, then stopped
flat, then fast stopped, then steep
there and back out, then home again
0 / 4 matched

Disciplinary Core Idea: PS2.A Forces and Motion — the motion of an object is described by its position, direction, and speed (NGSS Lead States, 2013). This unit carries the motion half; Forces (stop #06) brings the pushes, and together they feed MS-PS2-2. Crosscutting Concept: Scale, Proportion, and Quantity — speed is a ratio, and the graph makes it visible.

One more word · direction required

Velocity = speed + a compass

"6 cm/s" is a speed. "6 cm/s east" is a velocity. Direction is the upgrade — and it's why the round trip gets weird.

+5 cm/s

Outbound, heading east along the ruler. Positive direction, positive velocity.

−3 cm/s

Coming home, heading west. Same ruler, opposite sign. The minus is a direction, not a debt.

0 cm/s avg

Out and back to the exact start: zero displacement, zero average velocity — despite never standing still.

Myth-busters · tap to flip

Unlearn these three things

Manipulative 05 · Spaced repetition

Say it like a scientist

Twelve words. Flip the card, grade yourself honestly, and the deck schedules your next review — hard words come back sooner. Come back tomorrow and it remembers you. (It lives in your browser, no account.)

due now
locked in
seen so far

flip the card, then grade yourself

Practice · Math skills

Can a graph tell you who won?

The beetle's frames become a table, the table becomes speeds, and the speeds settle the argument. Unit rates, distance–time graphs, and the fastest human in intervals. Print it, solve it, check the key.

Exit ticket · 5 questions

Before you leave the track

No grade, no stakes — just proof the slope stuck. Answer all five to earn the stamp.

question 1 of 5

Every race tells a story.
Read the slope.

Back to the trail Course Map