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Heat

12

12

Some selected temperatures in degrees Celsius (°C)

 

6000 

surface of the sun

 

2500 

filaments in a lamp

 

1535 

iron melts

 

1063 

gold melts

  950 to 1200 

flame of gas burner

 

800 

match flame

 

357 

mercury boils

 

327 

lead melts

 

270 

electrical soldering iron

 

220 

smoothing iron (linen setting)

 

100 

water boils

 

78 

alcohol boils

 

57,8 

highest air temperature ever measured on Earth

 

36 to 37 

body temperature of healthy human being

 

water freezes

 

-39 

mercury solidifies

 

-89,2 

lowest air temperature ever measured on Earth

 

-180 

air liquefies

 

-273 

lowest possible temperature (absolute zero)

Evaporation 

The conversion of a substance from the liquid state into the gaseous state 
is referred to as evaporation.

There are two methods of evaporation: boiling and vaporization.

If water is heated to 100 °C, bubbles rise to the surface because the water 
particles start moving rigorously as a result of the heat supply. The water 
“boils”. The rising bubbles contain an invisible gas: water vapour.

Vaporization is the name given to the process when a liquid evaporates 
at a temperature below its boiling point.

 In this case, only particles on the 

liquid surface enter the gaseous state.

Condensation

The reverse process to evaporation, i.e. the conversion of a substance from 
the gaseous state into the liquid state, is known as condensation.
Small droplets of liquid form from the invisible gas over the boiling water 
upon cooling and can be observed as a cloud or mist.

Содержание 31799

Страница 1: ...Lehrerheft zur Experimentierbox Experiment description Manual Heat With work sheet ...

Страница 2: ...Heat 2 2 ...

Страница 3: ...liquid 9 1 11 Experiment 11 What happens when steam cools down 10 1 12 Experiment 12 The water cycle 10 1 13 Experiment 13 How water particles unite 11 2 Underlying principles 11 Worksheet 13 2008 Cornelsen Experimenta Berlin All rights reserved The work and parts of it are protected by copyright Every use for other than the legal cases requires the previous written agreement by Cornelsen Experime...

Страница 4: ... W 230 V 12891 14 1 Funnel plastic 70 mm Ø 12956 15 1 Tube brush 12964 16 1 Beaker glass 250 ml heat resistant with graduation 12905 17 15 Plastic containers for activities 12883 18 15 Rubber stoppers with bore 12840 19 15 Bridge shaped stands 12824 1 Thermometer model for demonstration 12948 Enclosed printed material 1 Experiment description Manual Heat 317996 1 Storage plan Heat 3179936 Addition...

Страница 5: ...Heat 5 Storage plan ...

Страница 6: ... peg red 12 1 peg blue 12 1 rubber stopper 18 1 bridge shaped stand 19 Additionally 1 thermos flask containing cold water or ice cubes 1 3 Experiment 2 Heating and cooling methylated spirits inflammable The Erlenmeyer flask is filled to the brim with coloured methylated spirits Then the rubber stopper is inserted in the flask The glass tube is inserted in the stopper Because methylated spirits is ...

Страница 7: ...ture in the lukewarm water regardless of whether it has been held in hot or cold water beforehand Therefore thermometers have to be used for exact temperature measurements Materials 1 thermometer 3 C to 103 C 5 3 insulating cases for beaker 8 3 plastic beakers 9 Additionally 1 thermos flask containing hot water 1 thermos flask contain ing ice cold water tap water 1 5 Experiment 5 The Celsius scale...

Страница 8: ...s etc For reading exercises and entries the worksheet at the end of this manual should be photocopied Material 1 thermometer 3 C to 103 C 5 1 7 Experiment 7 Converting a liquid into a gas Close the Erlenmeyer flask with the rubber stopper invert it and place on the stand Place a drop of Eau de Cologne or methylated spirits on the middle of the base of the flask using a dropper The drop becomes sma...

Страница 9: ...periment 9 Vaporizing liquids are cooling With a thermometer you determine the room temperature and the tempera ture of methylated spirits inflammable filled in a plastic beaker As the thermometer is pulled out of the liquid the temperature shown by the thermometer is decreasing Due to the evaporating methylated spirits on the thermometer This cooling effect can also be felt by wetting a finger wi...

Страница 10: ...on the cool base of the container They condense Materials 1 immersion heater 13 1 heat resistant beaker 16 1 plastic container 17 Additionally 1 thermos flask with ice cubes 1 12 Experiment 12 The water cycle Water evaporates everywhere Invisible water particles rise from the sea from fields and forests These evaporated water particles condense where the air is colder and form mist clouds When the...

Страница 11: ...ometers Liquid thermometers consist of a liquid filled container the bulb connected to a very narrow tube If the temperature rises the liquid will expand The level of the liquid in the tube at any given time can be read from a scale Thermometers are usually filled with alcohol or mercury On the Celsius thermometer scale the freezing point of water is marked at zero degrees Celsius 0 C and the boil...

Страница 12: ...from the liquid state into the gaseous state is referred to as evaporation There are two methods of evaporation boiling and vaporization If water is heated to 100 C bubbles rise to the surface because the water particles start moving rigorously as a result of the heat supply The water boils The rising bubbles contain an invisible gas water vapour Vaporization is the name given to the process when ...

Страница 13: ...Heat 13 Worksheet Cornelsen Experimenta 1 Reading exercises Write down the temperatures shown by the thermometers ...

Страница 14: ...at 2 Insulated wide neck vessels 3 pcs For the appropriation of warm and cold water as well as ice cubes for thermometer and temperature compound experiments In a storage tray with lid Content of each vessel 1 liter Order no 36680 ...

Страница 15: ......

Страница 16: ...nelsen Experimenta Berlin 03 00 Holzhauser Straße 76 Tel 49 30 435 902 0 eMail info corex de D 13509 Berlin Germany Fax 49 30 435 902 22 Internet www corex de Experiment description Manual Heat Order no 31799 6 ...

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