Spring motion span: what changes when the starting distance increases?

Learning Outcomes

Use the Spring remote lab to compare three curated starting distances.
Distinguish starting distance, amplitude, and high-to-low motion span.
Calculate two span increases from real distance-time traces.
State a broad relationship without claiming exact proportionality from noisy video tracking.

Student activity preview

Activity Content

Preview only. In a class session, students can fill in responses and submit their work to the teacher.

Two equal steps: does the span grow steadily?

7 min

Vehicle suspension engineers test how far a system moves after different disturbances. If the starting displacement increases by the same amount each time, will the spring's motion span also increase by roughly the same amount, or will the response become irregular?
You will test that question with real recordings of the same spring and mass. The starting distances are 20 mm, 35 mm, and 50 mm: two equal increases of 15 mm. The recordings include normal damping and small tracking steps, so the goal is a sound broad comparison rather than perfectly matching numbers.

The real Spring apparatus

Real laboratory view with a vertical spring on the right, a red cylindrical mass hanging from it, colored tracking markers, and other unused apparatus in the background. — Watch the red cylindrical mass on the right. The colored markers help the lab turn its motion into a distance-time trace.

Two quantities must stay distinct:
- Starting distance: the slider setting before the mass is released.
- Early motion span: the first adjacent high value minus low value after the curve begins repeating. This high-to-low span is about twice the amplitude and avoids estimating the equilibrium position, but both graph readings remain approximate.

What do you predict for the two equal 15 mm increases in starting distance?

The early motion span will stay about the same at all three settings. The span will increase in both steps, but by noticeably different amounts. The span will increase in both steps, by broadly comparable amounts.

Use the same early high-low pair every time

5 min

Use exactly 20 mm, 35 mm, and 50 mm, in that order. Set each value with the vertical slider. The nearby text box is not the control for this activity.
For every run, read the first adjacent high and low after the curve begins repeating. Ignore the lifting/setup part before release and the later damped tail. Do not combine a high from one cycle with a low from a later cycle. Estimate the vertical span as:
approximate high value - approximate low value
For example, a high of 6 mm and a low of -4 mm give a span of 6 - (-4) = 10 mm. These example values only demonstrate subtraction; use the values from your own recording.

Which evidence window gives the fairest comparison?

The first adjacent high and low after the curve begins repeating in each run. One isolated spike anywhere on the trace. The lifting section or a much later, strongly damped section.

Run 20 mm, 35 mm, and 50 mm

20 min

Open the lab from this activity and complete the same sequence three times.

Open the Spring lab

Set the vertical slider to 20 mm and select the green Start experiment now / Comenzar experimento button.
Watch the red mass. After the curve begins repeating, read the first adjacent high and low from the vertical axis.
Switch or scroll back to this activity and complete the 20 mm row before restarting the lab.
Select Restart experiment / Reiniciar experimento. Repeat the same steps at 35 mm, complete its row, and then repeat at 50 mm.
After the 50 mm row is complete, return to this activity and mark the lab block done.

Complete only the three preset rows below. If the table UI offers an extra empty row, leave it blank. High and low values may be negative. Use sensible whole-number estimates; pixel-level precision is not required. In Quality note, record one visible feature such as clear first high-low pair, small tracking steps, or damping visible.

Three-run Spring evidence

Use exactly the three preset rows. For each run, read the first adjacent high and low after the curve begins repeating, calculate span as high minus low, and add one honest quality note. Leave any extra row blank.

Starting distance mm	Approx. high mm	Approx. low mm	High-to-low span mm	Quality note

Compare the two equal starting-distance steps

8 min

Calculate two changes from your table:
- 35 mm span - 20 mm span
- 50 mm span - 35 mm span

Which claim best matches your three runs?

The motion span stays about the same at all three settings. The readings prove perfect proportionality with no measurement limits. The span grows, and the two equal starting-distance steps add broadly comparable amounts. The span changes, but the two increases are not broadly comparable in my readings.

Write one or two sentences that cite all three spans and both calculated span increases. State whether the two increases are broadly comparable or not, using approximate language that matches your readings.

Judge what the evidence can support

2 min

Your graph may show damping, tracking steps, or values that are difficult to read exactly.

Which interpretation is scientifically strongest?

The three recordings prove an exact mathematical law with zero uncertainty. The three runs and two comparisons can support a broad relationship, but those features limit precision. Any damping or tracking step means all evidence must be discarded.

Answer the investigation question

2 min

In 1-2 sentences, answer: Do equal increases in starting distance produce broadly comparable increases in early motion span? Then state whether you maintain or correct your initial prediction.
Your three spans, two calculated increases, and measurement limitation are already recorded above; do not repeat them here. A supported yes or no answer is acceptable.