Chemistry
2.1 Solids, liquids and gases
Matter: Anything that occupies space and has weight or mass.
Solids
Matter
Liquids
Gases
1.Solids : Keep the same shape. Solids take up the same amount of
space. Solids cannot be compressed.
2. Liquids: Take the same amount of space of the container their in.
Liquids can be poured. Liquids volume does not change.
3. Gases: Gases can flow. Gases can be compressed easily. Its
volume can change.
Particle theory
Solids: Particles are arranged in a fixed pattern, held together
strongly and are tightly packed together. Solids can vibrate but they
stay in the same place.
Liquids: The particles touch each other, they are held together
weakly and can change shape.
Gases: Particles don’t touch each other, and change shape.
2.2
Change of state
The posses in which gases turn into water is called condensing,
from liquid to solid is called freezing, from solid to liquid is called
melting, and from liquid to gases is called evaporation.
Measuring volume
To measure volume you need a measuring cylinder, the curve on
top is called meniscus.
Measuring temperature
To measure temperature you need a thermometer. The liquid
inside it expands as it gets hotter, so it rises up inside the
thermometer.
2.4
The water cycle
Our bodies are made up of at least 60% water.
The energy of the sun heats the Earth and the temperature of the water
sources, when this happens the water turns into water vapour, and moves to
the atmosphere which is called evaporation. Water can also evaporate into
the atmosphere from plants this is called transpiration.
As the water vapour goes up into the atmosphere, it cools down into drops of
rain in the air forming clouds. This process is called condensation.
When the water droplets in the clouds become too heavy for the air to hold
them, the droplets fall back as rain, snow, heal, and sleet. This process is
called precipitation.
The precipitation that falls then collects in open waters. Some water will sock
into the ground water. Water that reaches the surface of the land may flow
directly across the ground into the rivers, lakes, and oceans. This water is
called surface run-off.
2.5
Democritus is the man who discovered atoms.
Atoms mean cannot be divided.
Nano-tubes Nano mean very, very, small.
Sciences have discovered 94 different types of atom that occur in naturally in
the universe, another 24 kinds of atoms have been made in laboratories.
Some substances are made up of just a single kind of atom. A substance
made of just one kind of atom is called an element. For example, carbon is
made only of carbon atoms. Gold is only made of gold atoms.
In the periodic table rows are called periods and columns are called groups.
From left to right the atoms increase in mass, hydrogen atoms have the
smallest mass, then helium atoms and so on.
Each element is given a symbol.
Sometimes the symbol is the first letter or the first and second or by its
accent name. The first letter is upper case and the second letter is lower case.
