Friday, February 26, 2010 7:43 AM

Temperature

♥Group 4
-Dayana (Group Leader)
-Joey (Doer)
-Shabana (Doer)
-Yucen (Time Keeper)
-Si Hui (Observer)
Theme: Physical Quantities, SI Unit and Mearsurements
iv. Temperature

What is temperature?
Answer: Temperature is the measurement of how hot or cold something is.
Temperature is the amount of heat in a substance.

What is heat?
Answer: Heat is the energy in the substance. (Heat is an energy)

What is the SI Unit for temperature?
Answer: The International System of Units (SI) for temperature is kelvin (Symbol:K)
*0 K = −273.15 °C
However, temperature is most commonly measured in degree Celsius or Fahrenheit.

What is used to mearsure temperature?
Answer: A thermometer. There are many kinds of thermometer to measure things at different situations.

What is a thermometer?
Answer: Thermometer is a greek work. "Thermo" means warm. "Meter" means to mearsure. There are two types of thermometer(primary and secondary thermometer). For primary thermometers the measured property of matter is known so well that temperature can be calculated without any unknown quantities.
Secondary thermometers are most widely used because of their convenience.Secondary thermometers are usually more sensitive than primary ones.

Types of termometer:
*Alcohol thermometer
*Beckmann differential thermometer
*Bi-metal mechanical thermometer
*Coulomb blockade thermometer
*Galileo thermometer
*Infrared thermometer
*Liquid crystal thermometer
*Medical thermometer (e.g. oral thermometer, rectal thermometer, basal thermometer)
*Mercury-in-glass thermometer
*Pill thermometer
*Recording thermometer
*Resistance thermometer
*Reversing thermometer
*Silicon bandgap temperature sensor
*Six's thermometer- also known as a maximum minimum thermometer
*Thermistor
*Thermocouple
*Phosphor thermometry, phosphorescence can be used to detect the temperature of an object
eg a gas turbine component

Common thermometers:
*Liquid-in-glass thermomether. (mercury and alcohol) [Usually used in laboratory]
Why?
This thermometer relies on the expansion of liquids with respect to heat, to accurately measure temperature.

Mercury is commonly used in thermometer because it is sensitive to temperature change and expandsd also linarly with temperature. It means that for every unit temperature change, it expands by a constant and significant amount.Mercury has a low freezing point and it remains as at liquid form at room temperature. Mecury mearsures from -10 degrees celsius to 110 degree celsius.

Alcohol is usually used in thermometers when there is a need to mearsure very low temperatures as it has a lower freezing point then mercury. Alcohol mearsures from -117 degree celsius to 78 degree celsius.

*Clinical thermometer
The clinical termometer is used to mearsure body temperature within a range of 35 degree celsius to 45 degree celsius. The traditional thermometer has a constriction to prevent mercury from flowing bacl into the bulb when the thermometer is being removed from the body. The normal human body temperature is 36.9 degree Celsuis.

*Digital Thermometer
Now, the most commonly seen thermometer is the digital thermometer. It is so convenient to use it as it only requires a touch of a button. Some thermometers take temperature for the ear, while others take temperature orally.

The accuracy of the thermometer is very important. We can sence how hot or cold a substance is by touch it but it will not be accurate method of mearsuring temperature. For instance, one is unable to accuratrly tell if another is having a fever simply by putting a hand on the forehead.

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How to use a laboratory thermometer (mercury)?

Safty comes first! Always remember to wear safty goggles before starting an experiment.
The end, thankyou for reading out science project. God bless!