12 experiments found
Clear filtersAn endangered species can recover when its habitat is protected and hunting stops; losing habitat and poaching can wipe it out
Follow 100 one-horned rhinos for 20 years. Protect them in a national park, add community guards, or let their forest be cut and poachers hunt them, and watch their numbers rise or fall.
Minerals are natural solids found in rocks; metallic minerals (ores) shine like metal and give metals such as iron and copper, while non-metallic minerals give materials such as cement, glass and talc
Test eleven minerals for lustre, streak and hardness, find out what each is used for in Nepal, and sort them into metallic minerals (ores) and non-metallic minerals.
Sunlight, wind and tides never run out; forests, wildlife, fish and groundwater grow back if used wisely; coal, petroleum, natural gas and minerals took millions of years to form, so once used they are gone
Find out how long twelve natural resources take to replace and what we use them for, from sunlight and wind to forests, groundwater, coal and petroleum, and sort them by whether they can run out.
The air quality index (AQI) turns the amount of fine particles (PM2.5) into a number from 0 to 500; India's scale has six bands, good, satisfactory, moderate, poor, very poor and severe, each with its own health advice
Change the amount of fine dust (PM2.5) in the air and watch the air quality index move from good to severe. Learn what each band means for your health and where the dust comes from.
Fine-grained soils with humus hold more water than sandy soils
Pour the same amount of water through sandy soil, garden loam and clay soil in funnels, and measure how much drains through each.
Biodegradable waste is broken down by decomposers into harmless substances; non-biodegradable waste stays in the environment for hundreds of years
Find out what happens to different kinds of waste buried in soil for three months, and sort household waste into biodegradable and non-biodegradable.
Settling and filtering remove particles; only disinfection makes water safe from germs
Clean muddy river water step by step: let it settle, filter it, then kill the germs by boiling or with a chlorine tablet.
Electricity and fuel cost money and resources, and making them often pollutes the air; small habits, such as switching off, using LED bulbs and covering pots, save energy, while leaving things on or open wastes it
Look at twelve everyday habits, from switching off lights and cooking with a lid to leaving the TV on standby. Find out why each one saves or wastes energy, and sort them.
1 mm of rain on 1 m² of roof is 1 litre of water, so a roof collects area × rain × 0.8 litres (some splashes or soaks away): even a small roof can store a lot of water in the monsoon
Choose the size of a roof and the rain in a month, and work out how many litres of rainwater a family could collect in a tank, and for how many days it would give a family of five their water.
Trees take carbon dioxide from the air by photosynthesis and store the carbon in their wood: a grown tree takes about 21 kg of CO₂ a year, while a car gives out about 0.17 kg every kilometre
Plant 1, 10 or 100 trees and let them grow for 1 to 20 years. Find how much carbon dioxide they take from the air, and how many kilometres a car could drive to give out the same amount.
Burning petrol and diesel gives carbon dioxide, a greenhouse gas: kg of CO₂ = km travelled × kg per km per person, so walking or cycling gives none, a shared bus gives little, and a car gives the most for each student
Choose how you get to school, how far it is, and for how many days. See how many kilograms of carbon dioxide the trips put into the air, and how many trees it would take a year to soak it up.
The Earth turns 360° in 24 hours, so 15° of longitude is 1 hour: places to the east see the sun first and their clocks are ahead; each country sets its standard time from a longitude near its middle
It is noon in Kathmandu. What time is it in London, Delhi, Tokyo or New York? Pick two cities and see how the turning Earth gives every country its own clock time, and why Nepal is 5 hours 45 minutes ahead of London.