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1. Science and Technology K–6 · Year 3

   Is yeast alive? Sugar, warm water and a balloon

   A living thing takes in food and gives off waste, so a packet of dry yeast that inflates a balloon when fed sugar shows a characteristic of life that flour does not.

   PracticalLow risk

2. Science and Technology K–6 · Year 4

   Mini greenhouse: designing a home for a salad crop

   A sealed clear container keeps seeds warm and damp because water that evaporates condenses on the lid and runs back down, so a designed environment can supply what a food plant needs to germinate and grow.

   PracticalLow risk

3. Science 7–10 · Year 7

   Seed germination and abiotic factors: temperature, water and salt

   Germination needs water and a suitable temperature but not light for many species, and each factor can be tested one at a time with a controlled comparison.

   PracticalLow risk

4. Science 7–10 · Year 8

   Yeast respiration: carbon dioxide output against temperature

   Living cells release carbon dioxide as they respire sugar, and the rate depends on temperature.

   PracticalLow risk

5. Investigating Science 11–12 · Year 12

   Control groups and blinding: a double-blind taste test with a binomial test

   Blinding, random order and a probability calculation separate a real ability to tell two products apart from chance and from expectation.

   Practical, model not builtLow risk

6. Investigating Science 11–12 · Year 12

   Reaction time from a falling ruler: reliability, sample size and outliers

   One measurement of reaction time is unreliable; repeated trials and larger samples shrink the uncertainty of the mean, and each outlier has to be judged against a stated rule rather than deleted.

   Practical, model not builtLow risk

7. Investigating Science 11–12 · Year 12

   Sample size and sample selection: drawing beads from a bag

   Small samples scatter widely around the true proportion and the spread shrinks with the square root of sample size, while a biased way of choosing the sample misleads at every size.

   Practical, model not builtLow risk

8. Technologies K–10 · Years 1–2

   From cream to butter: a dairy food made by shaking

   Cream from cows' milk turns into butter when hard shaking makes its fat droplets join together and separate from the liquid buttermilk.

   PracticalMedium risk

9. Technologies K–10 · Years 1–2

   Preparing a fruit platter: serves and safe food steps

   A standard serve of fruit is about 150 g, so weighing prepared fruit shows how many serves a platter holds and how to share it fairly.

   PracticalMedium risk

10. Technologies K–10 · Years 3–4

    From wheat grain to flour: milling by hand

    Milling breaks wheat grains into flour, and sieving separates the brown bran from the white endosperm flour, while the total mass stays the same apart from dust that escapes.

    PracticalLow risk

11. Technologies K–10 · Years 5–6

    Sowing depth: when do wheat seedlings emerge

    In a managed crop, sowing depth is a decision: a seed sown deeper must grow further on its stored food before reaching light, so it emerges later, which is why farmers set air seeders to a chosen depth.

    PracticalMedium risk

12. Technologies K–10 · Years 5–6

    Why bread dough rises: yeast and temperature

    Yeast ferments sugar in dough and gives off carbon dioxide that makes the dough rise, and it works faster in warm conditions, which is why bakers prove dough somewhere warm.

    PracticalMedium risk

13. Agriculture and Food 7–12 · Years 7–8

    Bicarbonate of soda as a raising agent: gas from heat and from acid

    Sodium hydrogencarbonate (bicarbonate of soda) works as a raising agent because it produces carbon dioxide gas when it is heated or mixed with an acid; the gas turns limewater milky, a sign that a new substance has formed, and the mixture loses mass as the gas escapes.

    PracticalMedium risk

14. Agriculture and Food 7–12 · Years 7–8

    Checking a food thermometer and the temperature danger zone

    Food-poisoning bacteria can multiply between 5 °C and 60 °C, so potentially hazardous food is kept at 5 °C or colder or at 60 °C or hotter, checked with a probe thermometer proven in an ice slurry.

    PracticalLow risk

15. Agriculture and Food 7–12 · Years 7–8

    Germinating seeds at three temperatures, in light and in darkness

    A seed needs water, oxygen and a suitable temperature to germinate but does not need light, so temperature changes the rate of germination far more than darkness does.

    PracticalLow risk

16. Agriculture and Food 7–12 · Years 7–8

    Growing bean seedlings in light and in darkness

    Seedlings in darkness still germinate but grow tall, pale and weak on their seed reserves, while seedlings in light stay short, turn green and keep gaining dry mass by photosynthesis.

    PracticalLow risk

17. Agriculture and Food 7–12 · Years 7–8

    Measuring humidity with wet and dry bulb thermometers

    Evaporation cools a wet thermometer bulb, and the difference between wet and dry bulb readings measures relative humidity, one of the growing conditions that affect plants and animals.

    Practical, model not builtLow risk

18. Agriculture and Food 7–12 · Years 7–8

    Soil in a jar: settling out sand, silt and clay

    Soil particles of different sizes settle through water at different speeds, so a shaken soil sample separates into layers, coarse sand at the bottom and fine clay on top, and particle size is what separates this mixture.

    PracticalMedium risk

19. Agriculture and Food 7–12 · Years 7–8

    Testing foods for starch with iodine (microscale)

    Iodine forms a blue-black complex with starch, so a drop test on small food samples shows which foods store carbohydrate as starch and which do not.

    PracticalLow risk

20. Agriculture and Food 7–12 · Years 7–8

    Why cut apple turns brown, and how acid dips and blanching stop it

    Cutting fruit lets an enzyme (polyphenol oxidase) use oxygen to turn natural phenolic compounds into brown pigments, so acid and antioxidant dips, cold, or heat that denatures the enzyme slow or stop the browning.

    PracticalLow risk

21. Agriculture and Food 7–12 · Years 7–8

    Yeast and the rise of bread dough at 20, 30 and 37 °C

    Yeast ferments sugar to carbon dioxide, and the gas trapped by gluten makes dough rise faster in warm conditions than in cool ones.

    PracticalLow risk

22. Agriculture and Food 7–12 · Years 9–10

    Blanching and enzymes: a catalase test on raw and blanched vegetables

    Enzymes in raw vegetables keep working after harvest and in the freezer, and blanching in boiling water denatures them, which a catalase test with hydrogen peroxide makes visible.

    PracticalMedium risk

23. Agriculture and Food 7–12 · Years 9–10

    Calculating the energy on a nutrition information panel

    The energy on a nutrition information panel is calculated, not burned: each gram of protein, fat, carbohydrate and dietary fibre is multiplied by a fixed energy factor and the results are added.

    Calculation and dataLow risk

24. Agriculture and Food 7–12 · Years 9–10

    Cooling cooked rice safely: the two-stage cooling rule

    Cooked rice is a potentially hazardous food, so it must cool from 60 °C to 21 °C within 2 hours and from 21 °C to 5 °C within a further 4 hours, and a shallow tray cools far faster than a deep pot.

    Practical, model not builtLow risk

25. Agriculture and Food 7–12 · Years 9–10

    Counting stomata with leaf surface impressions

    Stomata are the pores that let carbon dioxide in and water vapour out, and in most dicot leaves they are more numerous on the lower surface than the upper, while monocot leaves have them more evenly spread.

    Practical, model not builtLow risk

26. Agriculture and Food 7–12 · Years 9–10

    Egg quality: Haugh units, air cell depth and storage temperature

    As an egg ages its thick white thins and its air cell deepens, so measuring albumen height against egg mass gives the Haugh unit, the interior-quality measure used in United States grading and in egg research. Australian egg quality assurance instead runs under Egg Standards of Australia, a certification based on HACCP principles that sets no albumen grade, so the class measures interior quality by one scheme and compares it with the way the Australian industry assures quality.

    Practical, model not builtLow risk

27. Agriculture and Food 7–12 · Years 9–10

    Emulsifiers: keeping oil and vinegar mixed

    Oil and water separate into layers after shaking, but an emulsifier such as egg yolk or mustard keeps oil droplets dispersed so the mixture stays uniform.

    PracticalLow risk

28. Agriculture and Food 7–12 · Years 9–10

    Energy content of foods by burning them under a can of water

    Burning a food releases its chemical energy as heat, and the temperature rise of a known mass of water gives a measured energy that can be compared with the nutrition information panel.

    Practical, model not builtMedium risk

29. Agriculture and Food 7–12 · Years 9–10

    Field soil texture by the bolus and ribbon test

    How a moist ball of soil holds together and how long a ribbon it forms between thumb and finger estimates its clay content, and clay content controls how much water and nutrient a soil holds.

    PracticalLow risk

30. Agriculture and Food 7–12 · Years 9–10

    Germination test, thousand grain weight and the sowing rate

    The mass of seed to sow per hectare depends on the target plant density, the seed size (thousand grain weight) and the fraction of seeds that germinate and establish, so a germination count changes the sowing rate.

    Practical, model not builtLow risk

31. Agriculture and Food 7–12 · Years 9–10

    Incubating fertile eggs and candling the developing embryo

    A fertile egg develops into a chick over 19 to 21 days only while it is kept warm, humid and turned, and candling shows the embryo, its blood vessels and the growing air cell without opening the egg.

    PracticalMedium risk

32. Agriculture and Food 7–12 · Years 9–10

    Measuring transpiration with a bubble potometer on a balance

    Water evaporating from leaves pulls water up through the stem, so the rate a shoot takes up water rises with wind, warmth and light and falls in still, humid air.

    Practical, model not builtLow risk

33. Agriculture and Food 7–12 · Years 9–10

    Radish dry mass at five fertiliser levels

    Plants make sugars by photosynthesis but need nitrogen from the soil to build proteins, phosphorus to build nucleic acids and ATP, and potassium for growth, so dry mass rises with nutrient supply until something else limits growth.

    PracticalLow risk

34. Agriculture and Food 7–12 · Years 9–10

    Salt tolerance of crops at germination

    Salt in soil water makes it harder for seeds and roots to take up water, and crops differ in salt tolerance, which is why barley can be grown on land where faba beans fail.

    PracticalLow risk

35. Agriculture and Food 7–12 · Years 9–10

    Soil aggregate stability: the slaking and dispersion test

    Soil crumbs that fall apart in water (slaking) or cloud it with clay (dispersion) have poor structural stability, which leads to surface crusting, slow infiltration and erosion.

    PracticalLow risk

36. Agriculture and Food 7–12 · Years 9–10

    Soil pH in water and in calcium chloride

    Soil pH measured in 0.01 mol/L calcium chloride reads lower than in water because the salt releases acidity held on soil particles, and the calcium chloride figure is the standard used to decide on liming.

    PracticalLow risk

37. Agriculture and Food 7–12 · Years 9–10

    Washing out gluten from bread, plain and cake flours

    Wheat flour proteins (glutenins and gliadins) join into an elastic gluten network when wetted and kneaded, and how much gluten a flour forms depends on its protein content.

    PracticalLow risk

38. Agriculture and Food 7–12 · Years 11–12

    Asexual propagation: rooting cuttings with and without auxin

    A stem cutting grows new roots and becomes a clone of its parent, and the auxin in rooting powder speeds root formation, which growers use to propagate plants true to type.

    PracticalLow risk

39. Agriculture and Food 7–12 · Years 11–12

    Coagulating milk protein with rennet enzymes and with acid

    Milk proteins coagulate into curd when enzymes such as chymosin act on casein at about 37 °C or when acid is added, the functional property behind cheese making, and temperature changes the rate.

    PracticalLow risk

40. Agriculture and Food 7–12 · Years 11–12

    Designing a fair plant trial: replication, randomisation and a test of significance

    A difference between treatment means counts only when it is large compared with the variation between replicates, which replication and randomisation let the trial measure and a t-test judges.

    Calculation and dataLow risk

41. Agriculture and Food 7–12 · Years 11–12

    Effect of light on plant growth under shade cloth

    Plant dry matter comes from photosynthesis, so plants under heavier shade gain less dry mass, even when they grow taller.

    PracticalLow risk

42. Agriculture and Food 7–12 · Years 11–12

    Ethanol from sugar: following fermentation by mass loss

    Yeast ferments glucose to ethanol and carbon dioxide in a fixed ratio, so the mass of carbon dioxide lost from a fermenting flask tells how much ethanol, a biofuel, has been made.

    Practical, model not builtLow risk

43. Agriculture and Food 7–12 · Years 11–12

    Extracting DNA from split peas

    DNA, the material genetic engineering works on, can be released from plant cells with detergent, salt and a protein-digesting enzyme and seen as white strands when it precipitates in cold alcohol.

    PracticalMedium risk

44. Agriculture and Food 7–12 · Years 11–12

    Formulating a meat chicken ration for protein and energy (Pearson square)

    Mixing a low-protein energy grain with a high-protein meal in the right proportions meets a protein target, and checking the mixture's energy shows whether the ration also meets the energy requirement for that stage of growth.

    Calculation and dataLow risk

45. Agriculture and Food 7–12 · Years 11–12

    Gelation and protease enzymes: fresh and canned pineapple in jelly

    Gelatine sets because its protein chains form a network that traps water, and protein-digesting enzymes in fresh pineapple and kiwi fruit cut those chains so the jelly stays liquid unless heat has denatured the enzymes.

    PracticalLow risk

46. Agriculture and Food 7–12 · Years 11–12

    Growing-season rainfall and wheat yield potential

    In southern Australia wheat yield is limited mainly by water, so the rain from April to October, plus some stored summer rain, sets an upper limit on yield that growers compare with what they harvest.

    Practical, model not builtLow risk

47. Agriculture and Food 7–12 · Years 11–12

    Jam and jelly setting point: sugar, pectin, acid and temperature

    Jam sets when enough water has boiled off for sugar, pectin and acid to form a gel, which happens at 8 °F (4.4 °C) above the local boiling point of water, so the setting temperature falls with altitude.

    Practical, model not builtMedium risk

48. Agriculture and Food 7–12 · Years 11–12

    Legume root nodules: counting, cutting open and inoculation

    Rhizobia bacteria in legume root nodules fix nitrogen from the air, and nodules that are fixing are pink to red inside, so inspecting nodules shows whether a legume is supplying its own nitrogen.

    PracticalLow risk