Keep this light. Drop a ruler once between one volunteer's fingers to spark the wonder, then take a few quick guesses. How fast can your body react to what it sees?

Do not explain the method or set up the test yet. Have one ruler in hand for the demonstration drop.

This table is the children's on-screen content. Reveal it one row at a time, reading each row aloud and pointing at the body as you go: eyes see, message to brain, brain decides, message to hand. The full definitions are in the prose above, so the table cells are kept short as quick cues.

Head off a common mix-up: a slower catch does not mean someone is bad at it. Reaction times vary and they get faster with practice and full attention. Note for yourself: the hot-pan reflex is actually so fast because the signal travels through the spinal cord, not all the way to the brain to decide. Keep this simple for the class: the body just acts automatically to protect itself.

Demonstrate the full cycle in front of the class with a volunteer dropping for you: predict out loud, catch, read the centimetre mark where your top finger gripped, then say a conclusion. Model all four beats: I predict... I test... I observed... I think... so groups copy the whole pattern, not just the catch.

Show how to hold the ruler so the 0 cm end is at the bottom, between the catcher's open fingers, without touching it.

Also model finding the group's figure: catch three times, read the three centimetre marks aloud (for example 16, 12, 14), and show that the middle value is 14 (the one between the smallest and largest). The group reports just one middle value for each condition. Keep it to the middle of three, not adding and dividing.

The whole class tests the same single comparison (eyes ready vs distracted) so that everyone's data can be pooled fairly on one chart. Groups of three or four work well: one catches, one drops, one reads and records, then they swap.

Circulate while groups set up. Remind droppers to give no warning and to release cleanly. For each condition, each catcher finds the middle value of their three catches (the one between the smallest and largest). To get one group figure per condition, take the middle value of the catchers' middle values, or simply share each person's. Keep the dropper, ruler and start position the same so it stays fair.

Drive the data-recorder on the IWB. Two columns appear: Condition and Catch distance (cm). Collect one middle value per condition from each group as you go round, then enter just two rows for the class: Eyes ready and Distracted, using the middle (or roughly typical) value across the groups for each. Tap to show the bar chart.

Each row becomes one bar. Ask the class to read the chart: which bar is shorter? what does a short bar tell us about reaction time?

Have each group's feely-bag holding 3 or 4 safe everyday objects (a conker, a smooth pebble, a wooden block, a sponge). Pupils take turns: feel, describe, guess, then reveal. Keep it brief and observational.

Draw out that the brain takes in information from touch, not just sight, and reacts by naming the object. This is the second sense test alongside the ruler catch.

Display-only science-talk. Revoice pupil findings against the chart. Most classes find distraction slows reactions. That is a real result.

Connect to Irish life: reaction-time research helps make roads and sport safer, which is why drivers are warned not to use phones at the wheel.

Quick recap to close. Ask one pupil to name the stimulus in the ruler test and one to give an example of a reflex.

Hands-on homework: ask the children to try the touch-only game at home with an adult, feeling three objects in a bag, and to note one in their journal.