20 experiments found
Clear filtersParticles spread from a high concentration to a low concentration by diffusion, faster at higher temperatures
Put a drop of food colouring into still water at different temperatures and measure how far the colour spreads over time.
Water moves by osmosis through a partially permeable membrane from a dilute solution to a more concentrated one
Soak potato strips in sugar solutions of different strengths, weigh them, and find the strength at which they neither gain nor lose water.
Every species has a two-part (binomial) scientific name: the genus, written with a capital letter, then the species; closely related species share a genus, and genera are grouped into families, orders, classes, phyla and kingdoms
Read the scientific names of eleven animals and plants found in Nepal, from the tiger and the jackal to the peepal and lali gurans, look up their families, and sort them by genus.
Living things have changed slowly over millions of years (organic evolution); fossils, homologous organs, vestigial organs and connecting links are evidence that today's species came from common ancestors
Look at a shaligram from the Kali Gandaki, a bat's wing, the human appendix, Archaeopteryx and more. Find out what each tells us, and sort them by the kind of evidence for evolution they are.
When the diaphragm moves down, the chest gets bigger, the pressure inside falls and air flows into the lungs
Pull and push the rubber diaphragm of a bell-jar lung model, watch the balloon lungs fill and empty, and see what a hole in the chest does.
Humans have a double circulation: the right side of the heart pumps blood to the lungs, and the left side pumps oxygen-rich blood to the body
Follow a drop of blood from the body through the four chambers of the heart, the lungs and back out to the body, checking whether it carries oxygen at each stage.
Living cells respire, using oxygen and giving out carbon dioxide; respiration is controlled by enzymes and depends on temperature
Use a respirometer to measure the oxygen used by germinating, dry and boiled seeds at different temperatures, and test their gas with limewater.
Mushrooms are fungi: they cannot make food, so they absorb it from the straw; they grow best when it is warm (about 20 to 25 °C), the air is damp and the straw has been pasteurised to kill moulds
Grow oyster mushrooms on bags of straw. Change the room's temperature, the dampness of the air and how the straw was treated, and find the conditions that give the biggest harvest.
A dicot stem has protective, storage, transport and growing tissues; xylem carries water up and phloem carries food, arranged in a ring of vascular bundles
Look at a stained cross-section of a sunflower stem and label the epidermis, cortex, phloem, cambium, xylem and pith.
A tissue is a group of similar cells doing one job; animal tissues are epithelial (cover and line), connective (join, support and carry), muscular (contract to move) or nervous (carry messages)
Look at twelve parts of the human body under a microscope and find out what each does, then sort them into epithelial, connective, muscular and nervous tissue.
Body mass index compares mass with height: BMI = mass (kg) ÷ height² (m²); for adults 18.5 to under 25 is a healthy range, but children are still growing, so their BMI is checked on charts for their age and sex
Choose a mass and a height and work out the body mass index, BMI = mass ÷ height². See which adult band it falls in, and learn why doctors use age charts, not these bands, for growing children.
Energy used (kcal) ≈ MET × body mass (kg) × time (hours), where the MET says how many times harder than resting an activity is; harder play, a heavier body and longer play all use more energy
Choose a game or exercise, your body mass and how long you play, and work out how much food energy your body uses, in kilocalories and in rotis.
First aid is the help given before a doctor arrives: it keeps the person safe, stops things getting worse and gets them to proper care; some common habits, like ice on burns or sucking snake venom, harm or waste precious time
Twelve things people do for burns, cuts, nosebleeds, snake and dog bites, diarrhoea and someone who has fainted. Find out why each helps or harms, and sort the good first aid from the old habits that do damage.
Each case of a disease infects R₀ people when no one is immune; when more than 1 − 1/R₀ of people are vaccinated, each case infects fewer than one other and the disease dies out, protecting even those who cannot be vaccinated
Choose a disease, from flu to measles, and how many people in a town are vaccinated. See how many people each case infects now, how many must be vaccinated for herd immunity, and whether the disease dies out or keeps spreading.
Bacteria multiply by splitting in two; in warm food they can double every 20 minutes, so after n doublings one germ becomes 2ⁿ, which grows faster and faster
Start with one germ on a plate of food left out in the warm. Choose how often it doubles and how many hours pass, and watch one germ become thousands, then millions, which is why cooked food should not sit out for long.
The body loses water in sweat, breath and urine, so a child needs about 35 mL of water for every kg of body mass each day, more when playing hard and on hot days
Choose a body mass, the minutes of hard play and whether it is a hot day, and work out how much water a child needs in a day, in millilitres and in glasses.
Inherited traits are set by genes passed from parents to children; acquired traits are learnt or gained during life, from practice, injury or the surroundings, and are not passed on in the genes
Look at twelve traits, from eye colour and dimples to a scar, a suntan and the language you speak. Find where each comes from and whether your children could get it from you, then sort them into inherited and acquired traits.
A lack of one nutrient causes a deficiency disease: vitamin A night blindness, vitamin C scurvy, vitamin D rickets, vitamin B1 beriberi, iron anaemia and iodine goitre; foods rich in that nutrient prevent it
Twelve cards show a sign of poor diet, such as night blindness or a swollen neck, or a food that prevents one, such as carrots or iodised salt. Find out what each tells you, then sort them by the vitamin or mineral they are about.
Red cells may carry A, B and Rh antigens; a patient's blood attacks any A or B it lacks, and an Rh-negative patient reacts to Rh, so O− can give to everyone and AB+ can take from everyone
Check twelve donor and patient pairs, from O− to A+ and AB+ to O−. Find the antigens on the donor's red cells and the antibodies in the patient's blood, and sort each transfusion as safe or not safe.
Plants cannot move, so they spread their seeds away from the parent plant by wind, water, animals or bursting pods, and each seed or fruit has a shape that suits its way of travelling
Look closely at twelve seeds and fruits, from the dandelion's parachute to the coconut's husk and the burr's hooks, and sort them by how they travel: by wind, by water, by animals or by bursting pods.