Presevation Food - Drying Drying is a method of food preservation that works by removing water from the food‚ which inhibits the growth of bacteria and has been practiced since ancient times to preserve food.A solar or electric food dehydrator can greatly speed the drying process and ensure more-consistent results. Water is usually removed by evaporation (air drying‚ sun drying‚ smoking or wind drying) but‚ in the case of freeze-drying‚ food is first frozen and then the water is removed by sublimation
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conductor can pass on this energy much quicker. • Shiny‚ light surfaces reflect radiation the best. • Convection occurs with only liquids or gases. • Hot‚ light air rises‚ whilst cold‚ dense air sinks. This causes convection current in gases and liquids. • This occurs because fluids expand when heated making them lighter. • Vacuum flask: o Vacuum cuts out heat transfer by conduction and convection. o Glass is poor conductor so little heat conducted here. o Glass surfaces are silvery to reduce
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Multiple Choice 1. Air may best be described as __________. a. an element b. a compound c. a mixture d. none of these 2. Which one of the following is the most abundant gas in the atmosphere? a. oxygen b. argon c. carbon dioxide d. nitrogen 3. With which
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2831 5.1.3 (c) Palaeomagnetism and reversals in the Earths Magnetic field Origin of the Earths Magnetic Field The Earth’s magnetic field results partly from convection currents in the outer core and changes in the magnetic field may reflect changes in the pattern and strength of the convection currents in the outer core. Indeed‚ the rate of westward drift of the field indicates fluid flow at a rate of about 1 mm/s in the outer core. Ancient magnetism - Palaeomagnetism Evidence
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Geo assessment Mt Etna An eruption begins when pressure on a magma chamber forces magma up through the conduit and out the volcano’s vents. When the magma chamber has been completely filled‚ the pressure in the pipe will build up very high resulting in an explosion. When magma reaches earth’s surface it is called lava. It may pour out in gentle streams called lava flows or erupt violently into the air. Rocks ripped loose from the inside of the volcano or torn apart by the gas may be shot into the
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1 Heat and Gases Chapter 1 Temperature and Thermometers New Senior Secondary Physics at Work Oxford University Press 2009 1 1 Temperature and Thermometers Practice 1.1 (p. 10) 1 B 2 D 3 A 4 Temperature is a measure of the degree of hotness of an object. 5 (a) On the Celsius temperature scale‚ the lower fixed point is the ice point (0 C) and the upper fixed point is the steam point (100 C). (b) We can reproduce the lower and upper fixed points by using pure melting ice and pure
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Thermodynamics Section Review 9A: 1. Scientists believed that the caloric was a material but mainly that it was an invisible fluid consisting of self-repelling particles. Two examples include how gases expand according to Newton’s laws‚ and determining the speed of sound in air. 2. The first person to successfully challenge the caloric theory was Benjamin Thompson. Benjamin observed that a dull boring bit could generate more hat than needed to melt the entire cannon barrel. 3. The significance
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the ionosphere. Atmospheric density decreases steadily as altitude increases. As altitude increase so does the pressure relative to ground level. Figure [ 1 ]Earth ’s Atmosphere The troposphere is the area of Earth’s atmosphere in which convection takes place. It is the constant upwelling of warm air and the concurrent downward flow of cool air to physically take its place. When the Earth is heated by the sun‚ the air becomes warmer and expands therefore it becomes buoyant‚ less dense‚ and
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cold stress Goals: Long-term: Newborn will be able to sustain adequate/normal self thermoregulation. Short-term: Provide assistance and support to 2. Mother will verbalize possible methods of heat loss & demonstrate understanding of conduction‚ convection‚ radiation‚ & evaporation 2. Provide heat/warm the newborn using incubators‚ radiant warmer‚ swaddling‚ and skin-to-skin contact. 3. Maintain thermal neutral Outcome Criteria 1. Infant’s body temperature will remain within normal axillary range
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reducing the effects of thermal conduction‚ convection and radiation. Heat insulation can take different forms depending on the type of heat transfer involved. The question arises as to which solid material is good for heat insulation. Non- metals are good heat insulators. Examples of non- metals used as insulators include wood‚ glass and plastics. Gases are good insulators if you can stop them moving. This prevents them from transferring heat by convection. An example of trapped gases used as insulators
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