5º. Unit 7.Matter and Force.
Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space. If you are new to the idea of mass, it is the amount of stuff in an object. We talk about the difference between mass and weight in another section. Matter is sometimes related to light and electromagnetic radiation.
PROPETIES OF MATTER
Matter is everything around us. Matter is made out of tiny particles called atoms. Some atoms join together to make groups known as molecules.
Apart from its color, odor and tested, matter has other properties and can be found in three different states.
A physical property is any characteristic of matter that's observable. If you were to pick up an apple, how would you describe it? It's smooth, hard, red and tastes sweet. These are some observable properties.
In physics, the physical properties also include anything that can be measured. There are two very important physical properties:
- Volume is how much space matter takes up.
- Mass is the amount of atoms in a given object. (Atoms are the very tiny parts that make up matter, and the more there are, the more mass there is.)
Common Physical PropertiesAs we discussed, physical properties can be observable or measurable. Let's explore some of the common types of properties in each category:
Observable Physical Properties
- Physical state of matter (whether it is a liquid, solid, or gas)
Measurable Physical Properties
- Freezing point
- Boiling point
- Melting point
- Matter can be classified as pure substances and mixtures.
- Pure substances contains all the molecules of same kind whereas in mixtures molecules are different.
- Mixtures can be separated using different techniques like winnowing, filtration, sedimentation, decantation, distillation .
Some of the forces we are subject to are gravity (which keeps us on the Earth's surface), the centripetal force (the force that makes things move in circles) and friction (the force which makes things stick or slide).
Simple machines work by turning small forces into larger ones, allowing us to perform tasks with more strength or speed. Examples of simple machines are levers, gears, pulleys, wheels and screws.
What are forces?A force can be a push or a pull. For example, when you push open a door you have to apply a force to the door. You also have to apply a force to pull open a drawer.
You cannot see a force but often you can see what it does. Forces can change the speed of something, the direction it is moving in or its shape. For example, an elastic band gets longer if you pull it.
All objects have a force that attracts them towards each other. This is called gravity. Even you attract other objects to you because of gravity, but you have too little mass for the force to be very strong.
Gravitational force increases when:
- the masses are bigger
- the objects are closer
Gravity only becomes noticeable when there is a really massive object like a moon, planet or star. We are pulled down towards the ground because of gravity. The gravitational force pulls in the direction towards the centre of the Earth.