2.2 Thermal Properties

Devashish Pahadi

2.2 (A) : Thermal expansion of solids, liquids and gasesWhy do things expand on heating?

Expansion in solidsThe atoms in solids vibrate as the temperature rises which makes the atoms move further apart.

Expansion in liquids The atoms in liquid also move further apart, same as the atoms in solids.

Expansion in gasesIn the case of gases, we don’t have to allow the gases to expand if it gets hotter. If we put heat up gases in a sealed container, the pressure would build up.

Thermal expansion of solids, liquids and gases

2.2 (B) : Measurement of temperature

In the eighteenth century, Gabriel Fahrenheit created the Fahrenheit scale. The freezing point of water in this scale would be set at 32 degrees and the boiling point would be at 212 degrees.

After the discovery of the Fahrenheit scale, Anders Celsius made another scale using the boiling and freezing point as anchors. Anders Celsius proved the freezing point of water to be at 0 degrees and the boiling point to be at 100 degrees.

The Celsius scale, Fahrenheit scale and the

thermometer

2.2 (C) : Thermal capacity

Thermal capacity or heat capacity is a measurable quantity which shows the amount of heat required to change the temperature of a substance by a given amount.

The SI unit of thermal capacity is expressed in Joules (J) per Kelvin (K)

2.2 (D) : Melting and boiling

The process which changes a solid into a liquid form is called melting or fusion and the constant temperature at which a solid changes to a liquid form due to heat energy is called the melting point.

The process which changes a liquid substance into a gaseous state is called boiling or vaporization and the constant temperature at which a liquid changes into a gaseous state is called the boiling point.

The process of gas turning into liquid is called condensation.

The process of a liquid turning into a solid is called solidification.

States of matter and conversions

Bibliographyhttp://figures.boundless.com/17110/full/rail-buckle.jpe

http://www.globalspec.com/RefArticleImages/2CBF9BA9E7A30DB74A133B83C14FAD9D_img45_02.jpg

http://astarmathsandphysics.com/a-level-physics-notes/thermal-physics-and-gases/a-level-physics-notes-work-done-by-an-expanding-gas1-html-2cc39dec.gif

http://new.coolclassroom.org/files/discoveries/24/newtempscale.png

http://how-to-make-tips.com/wp-content/uploads/2014/06/clinical-thermometer.jpg

http://www.egullet.com/imgs/egci/cookware/cookware13.jpg

http://media.web.britannica.com/eb-media/21/166421-004-51082072.jpg

http://www.gcsescience.com/Interconverting-Solid-Liquid-Gas.gif