Fuel, Breath and Family Traits

You need: a stopwatch · a class recording sheet with no names · an open space

1. Sit still for two minutes. Count breaths for one minute and pulse for 15 seconds (multiply by 4).
2. Run or jog steadily for three minutes.
3. Immediately record breaths and pulse, then again every minute for five minutes.
4. Add your numbers to the class sheet under a code, not your name.
5. Plot the class average for each minute and describe the curve.

How you'll know: The graph rises steeply after exercise and falls back over a few minutes, and you can explain that muscle cells needed more oxygen for respiration.

Safety: Warm up first. Anyone with asthma or a health condition chooses their own level and keeps medication nearby. Stop if you feel dizzy.

Go further: Compare a walk, a jog and a sprint. Does recovery take longer after harder exercise?

You need: cress or mung bean seeds from one packet · 4 small trays or pots · cotton wool or potting mix · a dark cupboard · a ruler

1. Plant the same number of seeds from one packet in each tray.
2. Put one tray in light and watered, one in the dark and watered, one in light with little water, and one in light with plenty of water and some compost.
3. Measure the height of 10 seedlings in each tray every few days for three weeks.
4. Note colour, leaf size and stem thickness.
5. Decide: the seeds were closely related, so what caused the differences you see?

How you'll know: The dark tray's seedlings are tall, thin and pale, showing that the environment changes how inherited instructions show up.

Go further: Add a tray of a different cress variety grown in the same conditions. Now which differences are inherited?

You need: a clear plastic bottle with the bottom cut off · 2 small balloons · a Y-shaped straw or two straws · plasticine · a large balloon or rubber glove · a rubber band

1. Attach the two small balloons to the straws (the bronchi) and push them into the bottle neck, sealing with plasticine.
2. Stretch the large balloon or glove across the cut bottom and fix it with a rubber band. This is the diaphragm.
3. Pull the diaphragm down gently and watch the lungs.
4. Push it up and watch again.
5. Explain what happened using the words volume and pressure.

How you'll know: When the diaphragm pulls down, the space inside gets bigger, pressure drops and air rushes in to fill the balloons.

Safety: The teacher cuts the bottle; cover sharp edges with tape.

Go further: Which part of your body does the model leave out? Add ribs with card strips and explain how rib muscles help.

You need: a 2 L or larger plastic bottle marked every 100 mL · a tub or sink of water · plastic tubing · a clean mouthpiece or straw for each person · a recording sheet with codes, not names

1. Fill the bottle with water, cap it, turn it upside down in the tub and remove the cap under water.
2. Slide one end of the tubing up into the bottle.
3. Take the biggest breath you can and breathe out through your own mouthpiece into the tube in one long breath.
4. Read how much water was pushed out. That is your breath volume.
5. Repeat three times and use the middle result.

How you'll know: You have a repeatable measurement and can explain why it varies between tries.

Safety: Breathe out only; never suck on the tube. Each person uses a new mouthpiece. Stop if you feel light-headed. Wipe up spills.

Go further: Does breath volume change after exercise, or when you sit versus stand? Plan a fair test.

You need: large flowers (hibiscus, alstroemeria, gladiolus, lily or kōwhai if fallen blooms are available) · a chopping board and round-ended knife · tweezers · a hand lens · a microscope and slide · sticky tape and card · gloves

1. Remove the sepals and petals one at a time and tape them to the card.
2. Find the stamens. Each has a stalk (filament) and a pollen bag (anther). Tape one down.
3. Find the pistil in the centre: sticky stigma, the style below it, and the swollen ovary at the base.
4. Cut the ovary across and look for the tiny ovules with a hand lens. These can become seeds.
5. Tap pollen onto a slide and draw two grains under the microscope.

How you'll know: Your card shows every part, labelled, and you can explain the path pollen takes to reach an ovule.

Safety: Wear gloves for lily pollen, which stains. Keep lilies away from cats. Knives stay on the board.

Go further: Compare an insect-pollinated flower with a wind-pollinated grass flower. How is each shaped for its job?

You need: a zip-lock bag · 2 crackers · half a banana · water · orange juice · an old stocking or pantyhose leg · a cup · scissors · gloves

1. Crush the crackers and banana in the bag with your hands: that is your teeth doing mechanical digestion.
2. Add a splash of water for saliva and a splash of orange juice for stomach acid. Seal and squish for two minutes: that is stomach churning.
3. Cut a corner off the bag and squeeze the mush into the stocking held over a cup: the small intestine.
4. Squeeze gently. The liquid in the cup stands for nutrients absorbed into the blood.
5. What is left in the stocking goes on to the large intestine, where water is taken back.

How you'll know: You can name each organ the model stands for and say which steps are mechanical and which are chemical.

Safety: Check allergies first. Gloves on. Do not taste. Wash up and bin the waste.

Go further: Where do the liver and pancreas fit in? Add them to your model and explain what bile and pancreatic juices do.

You need: jelly crystals · hot water (teacher-poured) · clear plastic cups · fresh green kiwifruit · canned or boiled kiwifruit or pineapple · a spoon and chopping board · a fridge · gloves

1. The teacher makes the jelly and pours equal amounts into five cups once it has cooled a little.
2. Add a spoonful of mashed fresh kiwifruit to cup 1, boiled kiwifruit to cup 2 and canned fruit to cup 3. Cup 4 gets nothing (control). Cup 5 gets fresh kiwifruit added after the jelly has set.
3. Label and refrigerate overnight.
4. Tip each cup gently and record which set firmly, which are soft and which are runny.
5. Explain the results using the words enzyme, protein and heat.

How you'll know: Fresh kiwifruit stops the jelly setting because its enzyme breaks down the protein gelatine; heating destroys the enzyme, so boiled and canned fruit let it set.

Safety: Check kiwifruit and pineapple allergies. Gloves on, as the fruit can sting skin. The teacher handles hot water. Do not eat the jelly.

Go further: Test gold kiwifruit, pawpaw or fresh ginger. Which have the strongest protein-digesting enzymes?

You need: a bag of dried peas of mixed colour or shape, or fresh pods · green and yellow beads or counters · two paper cups · a tally sheet

1. Sort 100 peas into yellow and green (or round and wrinkled) and tally them.
2. Model Mendel's cross: each pea plant carries two factors. A pure yellow parent is YY and a pure green parent is gg.
3. Put one bead from each parent into a cup to make the first generation. They are all Yg and look yellow, because yellow is dominant.
4. Now cross two Yg plants: each parent cup holds one Y and one g bead. Draw one from each cup 40 times and record the pairs.
5. Count how many look yellow and how many green. Compare with Mendel's 3 to 1 ratio and your real peas.

How you'll know: About one in four of your bead pairs are gg (green), showing how a hidden factor can reappear in the grandchildren.

Go further: Look up the seven pea traits Mendel studied and predict which trait was dominant in each pair.

You need: a desk fan · paper spinners you make · fluffy seeds such as dandelion or toetoe · fleshy fruits · burrs or hooked seeds · a few kōwhai seeds · a jug of salt water · a tape measure · gloves

1. Drop each seed or spinner from the same height in front of the fan on low. Measure how far it lands.
2. Repeat each five times and find the median distance.
3. Drop kōwhai seeds into salt water and check whether they are still floating after a day.
4. Brush hooked seeds against a wool jersey. Do they stick?
5. Sort the seeds by method: wind, water, animals, or bursting.

How you'll know: You can match each seed's shape to how it travels, using your measurements as evidence.

Safety: Kōwhai seeds are poisonous: gloves on, no eating, wash hands afterwards. Collect only fallen seeds and fruit.

Go further: Design a paper spinner that stays in the air longest and explain why it works, then find a native seed with a similar shape.