Matter Around Us

Unit 3

Matter Around Us

Learning Objectives

At the end of the lesson you will be able to

* Define matter and develop an understanding of the particulate nature of matter

* Sort the objects on the basis of certain properties

* Differentiate between solids, liquids and gases based on the arrangement of their particles.

* Differentiate between pure substances and mixtures

* Identify the need for separation of mixtures

* Suggest suitable methods for separating given samples of mixture

*  Acquire an  awareness on food adulteration and its harmful effects

Introduction

Matter is all around us. The air you are breathing is also a matter. Matter is defined as anything that has mass and takes up space. Matter is found in three major states; solid, liquid and gas. So what is matter made of? All matter is made of atoms. Atoms are the smallest particle of matter.

They are so small that you cannot see them with your eyes or even with a standard microscope. A standard sheet of paper is about millions atoms thick. Science has come up with a technology to identify structure of atoms Scanning Electron Microscope (SEM) and Tunnelling Electron Microscope (TEM) which uses electricity to map atoms. There is more about atoms in the later, but first let's learn about the three states of matter. Silicon atoms on a surface via Scanning Tunneling Microscopy, (STM).

Activity – 1

Take a few crystals of sugar. Observe them carefully with the help of a magnifying lens.

Which of the shapes given above resembles a sugar crystal?

A B C D E F

Answer: D

Now place a few sugar crystals in a teaspoon full of water. What happens to the sugar crystals?

Answer: Like everything else a sugar crystal is also made up of molecules. When sugar dissolves in water, the sugar crystals break down and the molecules of sugar get distributed in the water. This makes the water taste sweet. The sugar molecules are extremely small, that is why we are not able to see them. A small amount of any matter will have many million molecules. (1 million = 1000000)

Like everything else a sugar crystal is also made up of molecules. When sugar dissolves in water, the sugar crystals break down and the molecules of sugar get distributed in the water. This makes the water taste sweet. The sugar molecules are extremely small, that is why we are not able to see them. A small amount of any matter will have many million molecules. (1 million = 1000000)

Besides solids, Liquid and gases there are two more states plasma and Bose – Einstein condensates.

Plasma is not a common state of matter on Earth, but may be the most common state of matter in the universe. For example, stars including sun are covered in plasma.

Bose – Einstein condensate is a gas – like state of matter that exists at extremely cold temperatures. It was predicted around 1925 and confirmed in 1995, This is used in the field of cryogenics.