“What happens when (k) grows?” Three verbal explanations lose to one live drag in front of the class.
That’s what visualization is for: change a condition, watch the picture update. Pick a topic, move a slider—no software course required first.
Three places dragging helps
- Linear / quadratic: slope, intercept, opening—change one letter, see it.
- Shifts and stretches: (y=f(x-a)), (y=af(x))—guess first, then check.
- Geometry ties: angles, sides, circle and tangent—moving points beat static sketches.
A short lesson arc
- Ask: “If (a) goes from 1 to 2, what do you expect?”
- Open visualization, drag, compare to the guess.
- One-sentence summary from students, then write the general form cleanly in the formula editor.
Predict → observe → symbolize sticks better than handing out the answer key.
Visualization builds picture sense; it doesn’t replace definitions or proofs. Good for intro and consolidation; exam wording and homework still need formulas and written reasoning.
For this week’s function, open visualization for two minutes before you decide whether it belongs in the slides.