Heat transfer: conduction, convection, radiation, evaporation
No step-by-step – details in the entry.
Backpack cheat sheet
Cheat sheet: Survival science
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SurviveBetter · Cheat sheet
Survival science
Emergency 112 (EU) · Austria ambulance 144. A cheat sheet only reminds you – it is no substitute for training.
Physics
Understanding weather fronts: warm front and cold front
No step-by-step – details in the entry.
Caution: Your own weather observation supplements the official forecast but does not replace it. Before trips, check the forecast and severe-weather warnings from the national weather service.
How thunderstorms form
No step-by-step – details in the entry.
Danger: If you can hear thunder, you are within reach of lightning. Immediately seek shelter in a substantial building or a hard-topped metal vehicle and only go back out about 30 minutes after the last thunder.
Wind chill: why wind makes it feel colder
- Read the index – Weather services often state a feels-like temperature or wind chill in cold weather.
- Use a wind layer – Even a thin windproof outer layer keeps the warm air inside the clothing and greatly reduces the effect.
- Cover skin – Face, ears and hands are most affected – wear a hat, neck gaiter and gloves.
- Seek the lee – Take breaks behind rocks, buildings or in forest; choose a sheltered tent site.
Caution: In strong wind and cold, cover face, ears, nose and fingers and watch for white, numb patches of skin – they can be signs of beginning frostbite.
Dead air and why wet clothing chills
- Avoid sweating – Remove a layer before climbs, open zips – sweat from inside wets you just as much as rain.
- Keep rain out – Put on the rain and wind layer in time, before the insulating layer gets wet.
- Choose material deliberately – In cold and wet conditions use wool or synthetics rather than cotton; keep down dry.
- Change into dry – At camp swap wet clothing for dry before you cool down.
Caution: Wet clothing in wind and cold can lead to hypothermia, even above freezing. Carry a dry spare layer in waterproof packaging.
How a compass works: Earth's magnetic field and declination
- Look up declination – Take the current value for the location from the map (note the year) or an official calculator.
- Apply the correction – Account for declination when transferring between map and terrain, or use a compass with adjustable declination.
- Keep interference away – Hold the compass level and keep metal and electronics at a distance.
- Mind the world zone – When travelling to other continents check whether the needle is balanced for the region, otherwise it may drag.
Sound and light in signalling
- Whistle instead of shouting – Shouting is exhausting and soon makes you hoarse; a whistle stays loud with little breath and stands out from natural sounds.
- Use patterns – Rhythmic signals (groups of three, the alpine distress signal) stand out from random noise and are understood as distress signals.
- Choose a position – Signal from open, raised spots, not from hollows or dense forest; consider wind and the noise of streams.
- Use light deliberately – By day use a mirror with the sun, at night a lamp towards possible helpers; flashing signals attract more attention than steady light.
Air pressure and altitude
- Body – Lower oxygen pressure means ascending more slowly so the body can adapt – see high altitude.
- Cooking – At altitude cooking takes longer and needs more fuel.
- Calibrate the altimeter – Reset barometric altimeters at known elevations (summit, hut, map).
- Watch the pressure trend – If the altimeter rises although you are not climbing (for instance overnight in a hut), pressure is falling – a possible sign of…
Caution: Altitude illness can occur at high altitude. With symptoms do not go higher, and descend if things get worse.
Dew point: why tents get wet inside
- Ventilate – Keep vents open even when it is cold; air exchange carries the vapour out.
- Reduce moisture sources – Leave wet clothing and gear in the vestibule or a bag, do not dry them in the inner tent.
- Choose the site – Valley hollows and shores collect cold, humid air; slightly raised sites with some air movement are drier.
- Wipe in the morning – Wipe off condensation with a cloth and dry the sleeping bag when possible.
Danger: Do not cook inside a closed tent to dry or warm it – carbon monoxide and fire risk.
Solar radiation and UV
- Check the UV index – Weather services publish the UV index.
- Shade and clothing – Seek shade, wear a wide-brimmed hat and long sleeves – these protect more reliably than sunscreen alone.
- Sunscreen – Apply generously to exposed skin and reapply after sweating or swimming.
- Protect the eyes – Sunglasses with UV protection, with side shields on snow.
Caution: On snow, glaciers and water wear sunglasses with UV protection and side shields – snow blindness often appears only hours later.
How GPS works – and where it fails
- Clear view of the sky – For a good fix, move to an open spot, hold the device up and wait briefly until the displayed accuracy is stable.
- Download maps for offline use – Positioning works without mobile coverage, but the phone's map often does not.
- Check plausibility – If the position jumps, compare the display with the terrain and the map.
- Plan power – Airplane mode with location still on saves battery; keep the device close to your body in the cold and carry a power bank.
- Pass on coordinates – In an emergency, read out the coordinates in the agreed format and pass them on to rescuers.
Caution: Battery, cold, reception or a fall can make the device fail at any time. Always carry a paper map and a compass and practise using them.
Understanding electricity: voltage, current and why water conducts
- Respect mains voltage – Mains voltage is 230 volts in Europe and 120 volts in North America – both can be fatal.
- Know your protective switches – Residual current devices (RCDs) switch off when current leaks via the wrong path.
- Keep your distance outside – Stay away from damaged lines, pylons and substations; never fly kites or use fishing rods near overhead lines.
- Connect generators safely – Never feed a generator directly into household wiring except via a professionally installed transfer switch – otherwise back-feeding…
Danger: Always treat fallen or damaged power lines as live. Keep well away, warn others and call the grid operator or the local emergency number (112 in the EU).
Friction in rope: why knots and friction hitches hold
- Experiment: wraps – Wrap a cord once, twice, three times around a smooth pole and pull on one end while holding the other loosely.
- Dress and set the knot – A neatly dressed, firmly set knot has defined nips; a messy one can capsize or slip under load.
- Leave long enough tails – Under varying load, rope can creep through a knot.
- Watch out for slippery material – Slippery, stiff or very thin cords have less friction.
Caution: This knowledge explains principles. Life-critical belays require training, certified equipment and proven knots.
Rope strength: what weakens a rope
- Allow a safety margin – Never load a rope anywhere near its stated breaking strength.
- Soften edges and bends – Do not run ropes over sharp edges; use edge protection made of cloth or hose and choose large radii.
- Inspect regularly – Run the rope through your hands: hard, soft or thin spots, glazed areas from heat, damaged sheath, discolouration.
- Store correctly – Store dry, dark and cool, away from chemicals such as battery acid and solvents; dry the rope and remove grit before storing.
Danger: To secure people, use only rope and equipment tested and certified for that purpose – with training. Never use paracord, washing line or unknown ropes for people.
Fire behaviour: wind, slope and fuel
- Read the fuel – How fine, dry and continuous is the vegetation?
- Read the weather – Pay attention to wind, humidity and temperature.
- Read the terrain – Slopes, gullies and saddles act like chimneys.
- Apply it to your fire site – Place a fire on mineral soil, sheltered from wind, not at the foot of a vegetated slope, with distance from trees and overhanging branches.
Danger: Fires run considerably faster uphill than on the flat, especially in gullies and ravines. Never flee uphill ahead of a fire; leave early and call the local emergency number (112 in the EU).
Reading clouds and understanding weather forecasts
- Get the forecast – Before the trip read the forecast and warnings from the national weather service, especially thunderstorm and wind warnings.
- Understand probabilities – A chance of rain says how likely precipitation is, not how long or how heavily it will rain.
- Watch the sky – Look up regularly on the way: are heap clouds already growing tall in the morning?
- Decide in time – Set turnaround points and alternative routes in advance and turn back earlier than planned at signs of deterioration.
Caution: Towering clouds with dark bases, thunder or lightning: switch to thunderstorm safety immediately and leave exposed ridges and water. Weather rules from clouds do not replace warnings from weather services.
Moon phases and light at night
- Look up the moon phase – Look up the moon phase and moonrise for the date in a calendar, weather app or astronomical service.
- Plan night activity – For night walks or early starts, use the days around full moon and allow for sections in moon shadow (shaded slopes, forest).
- Let your eyes adapt – The eyes take about half an hour to adapt largely to darkness.
- Rough direction – Like the sun, the moon is roughly in the east when it rises and in the west when it sets.
Caution: Even bright moonlight is not enough to safely see steps, roots or drop-offs. Always carry a lamp and spare batteries.
Tides: why the sea rises and falls
- Tide table for the place – Take the high and low water times for the nearest reference port from official tide tables.
- Note the moon phase – Around new and full moon, high waters are higher and low waters lower – more exposed flats but also faster-rising water.
- Allow a buffer – Plan the return so you are back long before the tide comes in. Wind and air pressure can bring the water earlier.
- Observe on site – Channels, gullies and low spots fill first.
Danger: Incoming water can cut off coves, headlands and sandbanks faster than expected. Check the tide table, start back before low water, walk mudflats only with a local guide. If cut off, do not wade back through deep water – call the local emergency number (112 in the EU).
Chemistry and biology
Why boiling disinfects water
No step-by-step – details in the entry.
Danger: Never operate stoves or fires in tents, vehicles or enclosed spaces without adequate ventilation (carbon monoxide).
What happens in combustion
- Fire triangle – Fuel, oxygen and heat must come together.
- Pyrolysis and flame – The flame is burning gas above the wood.
- From thin to thick – Tinder and thin kindling provide enough heat to pyrolyse thicker wood – which explains the structure of every fire lay.
- Read the smoke – Lots of white to grey smoke often indicates damp wood or a fire that is too cool; a hot fire with good airflow smokes less.
Danger: Any combustion in enclosed spaces can produce carbon monoxide. No barbecues, stoves or fires in tents, living spaces or garages.
Carbon monoxide: why it is so dangerous
- Know the sources – Stoves, boilers, fireplaces, barbecues, camping stoves, generators, vehicle engines – every flame and every combustion engine.
- CO alarm – Install and test CO alarms according to the manufacturer in rooms with fuel-burning appliances.
- Take signs seriously – Headache, dizziness, nausea, tiredness – especially if several people or pets are affected at once and it improves outdoors.
- Get out and call – Get into fresh air immediately, call for help and have the fire service or professionals check before returning.
Danger: If carbon monoxide is suspected (headache, dizziness, nausea, drowsiness in several people, CO alarm sounding): get everyone into fresh air immediately, do not re-enter and call the local emergency number (112 in the EU).
Batteries in the cold
- Carry close to the body – Carry the phone, spare batteries and power bank in an inside pocket; take them into the sleeping bag at night.
- Swap rather than discard – Swap cold, apparently empty batteries for warm ones and rewarm the cold ones on your body – they often still deliver power.
- Choose chemistry deliberately – Choose battery types suitable for cold according to the manufacturer; check the device manual for permitted types.
- Avoid condensation – Bring cold devices into warm rooms in a sealed bag and let them warm up slowly there.
Danger: Never warm batteries with fire, a stove or hot air and do not use damaged or swollen batteries – fire and explosion risk.
Microbes in food: spoilage, fermentation and safety
- Understand the cold chain – Keep perishable food cold or keep it hot – do not leave it for hours in the range in between.
- Acid as protection – Pickled and lacto-fermented foods are safer because the acid inhibits pathogens.
- Use tested methods – Can low-acid foods such as vegetables, meat and beans only according to tested instructions; when fermenting, stick to the salt quantity…
- Work cleanly – Keep hands, jars and work surfaces clean – fewer unwanted microbes at the start mean a lower risk.
Danger: The bacterium Clostridium botulinum can produce a deadly toxin in airtight, low-acid foods at room temperature – often without any visible change. Use only tested recipes and methods for canning and preserving.
The human body
The body's water balance and dehydration
No step-by-step – details in the entry.
Danger: In case of confusion, reduced consciousness, fainting, no urine for many hours, or persistent vomiting and diarrhoea – especially in children, older and sick people – call the local emergency number (112 in the EU) or get medical help.
Heat index: humidity and sweating
- Note the feels-like temperature – Weather services often give a heat index or feels-like temperature in heat; heat warnings take humidity into account.
- Adjust exertion – In muggy weather slow down, rest in the shade and do strenuous work in the cooler parts of the day.
- Drink regularly – Replace lost water, even if sweat does not visibly evaporate.
- Help evaporation – Loose, airy clothing, air movement from a fan or wind, moistening the skin.
Danger: Confusion, reduced consciousness or a seizure in heat are an emergency: call the local emergency number (112 in the EU).
How hypothermia develops
- Early signs – Shivering, cold hands, feeling cold, declining fine motor skills.
- Stop heat loss – Get out of wind and wet, swap wet clothing for dry, insulate – including from the ground – and cover the head.
- Provide energy – If the person is awake and can swallow safely, warm sweet drinks and food help generate heat.
- Get help – With warning signs or if the condition does not improve, call for help and protect from the cold until help arrives.
Danger: With confusion, marked drowsiness, reduced consciousness or if shivering stops while the person is still cold: call the local emergency number (112 in the EU). Handle the person gently and protect from the cold.