Keep this light, just a curiosity hook. Have everyone go still and feel their chest or find a pulse. Take a few guesses out loud, but don't set up the investigation yet.

Say "Does exercise change how fast our heart beats and how fast we breathe?" and tell them this is our first real testable question of the year.

This is a display-only think-pair-share. Take two or three predictions out loud and revoice the reasoning ("so you think the pulse goes up because the body is working harder").

Pupils write their prediction on their Investigation Journal page. Don't confirm whether anyone is right, the test will tell us.

Pupil choice (real investigative decision): tell pairs they may choose which exercise to test, step-ups or jumping jacks on the spot, as long as both partners do the same one. This gives each pair a genuine choice within the same fair test.

This table is the pupils' on-screen content for 5th class. Read it together and physically point at each row as you read it, so each term is anchored one at a time rather than landing as a block. Pause after each row and ask a pupil to put it in their own words.

Pin the unit once and keep it everywhere: we always count for 15 seconds and multiply by 4, so every number is per minute. Never write a raw 15-second count under a per-minute heading.

Head off the common confusion: a faster pulse is not dangerous here, it is your body sensibly delivering more oxygen.

Demonstrate the FULL cycle on yourself or a calm volunteer, thinking aloud at every beat so pupils see the whole pattern before they run their own. The worked numbers above are now on the pupils' screen, so point at them as you say them:

• "I predict my resting pulse will be lowish because I am sitting still."
• "I press my fingers on my wrist. The timer starts... I count... 15 seconds, stop. I counted 18, so 18 × 4 = 72 beats per minute. I'll write 72."
• "Now breaths the same way: I counted 5 in 15 seconds, so 5 × 4 = 20 breaths per minute."
• "I observed my resting pulse is about 72. I think after the exercise it will go higher because my body will need more oxygen."

We count each thing once, carefully, not twice. After exercise the pulse drops quickly, so the first count straight away is the truest one, no averaging is needed.

Drive the fair-test-timer on the IWB for the 15-second counts so the whole class works to the same clock.

Pairs work from their Investigation Journal page. The page has four clearly-labelled boxes (resting pulse, pulse after, resting breaths, breaths after) so every pupil can see exactly where each number lands as they go. Use the IWB timer for the shared 15-second counts and the one-minute exercise. Remind them: count once for 15 seconds, multiply by 4, every single time, and write it straight in the right box.

Each thing is counted once, not twice. Measuring straight after exercise catches the real peak, because the pulse drops fast once you stop, so a single immediate count is the fairest.

Safety: anyone who should not exercise (asthma, injury, feeling unwell) is the timer-watcher and counter instead. Stop anyone who feels light-headed and have them sit. Clear the exercise area of bags.

Fast finishers: sketch a second prediction for what would happen after two minutes, or quietly help time the next pair, not on a device.

Drive the data-recorder on the IWB. The table has one row per pair, with four columns: Resting pulse (per minute), Pulse after (per minute), Resting breaths (per minute), Breaths after (per minute). Add a row for each pair. The config holds 16 rows, comfortably more than a full class of pairs, so the last pair always has a place to enter their numbers.

Show the chart, which draws the last column (Breaths after) as one bar per pair. Keep every number per minute (counted in 15 seconds and multiplied by 4).

Display-only science-talk. Draw out the big idea: the muscles needed more oxygen, so the lungs pulled in air faster AND the heart pumped it round faster, the two work as one oxygen-delivery team.

Revoice pupil findings and link back to predictions ("you predicted it would go up, and the class numbers show that too"). Predictions that did not match are still good science, the evidence is what counts.

If two pairs chose different exercises, ask whether they got a similar pattern, a nice link back to the choice they made earlier.

Quick recap; let pupils name one thing they learned. Homework (recorded on paper): ask an adult at home to feel their pulse resting, then after going up the stairs, and notice if it changed.