O I NWATCH OUT ICEBERG T C U D O R T N I Loud groans and moans echo through the water Something is happening deep inside the glacier Suddenly a massive piece of ice breaks off It falls into the sea with a huge splash It drifts away from its frozen home This floating ice is a new iceberg 4
Most glaciers look like solid walls rising from the sea Some have been around for thousands of years Cold temperatures keep glaciers solid But heat is a glacier’s enemy Rising temperatures can break glaciers apart In cold temperatures the water molecules slow down They bond together to form a solid mass of ice But as temperatures rise the molecules start to move around more They break their bonds The warm water under a glacier heats it up Melted water on its top also thins the glacier This can cause a glacier to crack If the crack is big enough an iceberg is born
WHAT IS TEMPERATURE Step outside and feel the heat of the sun’s rays It’s what makes Earth’s temperatures rise and fall Heat is a form of energy It can come from light like the sun’s heat It can also come from other sources Electricity and friction cause heat So does combustion Temperature is the The sun is a natural source of heat measurement of the amount of heat energy in an object When heat transfers from one object to another the temperature of each object changes Usually heat moves from a hotter object to a colder object This makes the hotter object have a lower temperature The colder object’s temperature goes up 1 R E T P A H C 6
MEASURE IT THERMOMETERS AND TEMPERATURE SCALES F C K BOILING POINT OF WATER 212 100 373 15 HUMAN BODY TEMPERATURE FREEZING POINT OF WATER 98 6 32 37 0 310 15 273 15 ABSOLUTE ZERO 459 67 273 15 0 A thermometer measures temperature It uses a temperature scale There are three main scales The Fahrenheit scale F is used most often in the United States The Celsius scale C is used in countries that use the metric system The Kelvin scale K is used in science Each scale shows a different measurement for the same temperature Imagine a pot of water on the stove It gets hotter and hotter until it starts boiling This boiling point is 212 degrees Fahrenheit 100 degrees Celsius and 373 15 degrees Kelvin The temperature of the water is the same It’s the number assigned to it that varies 7
