States of Matter

Matter is made of atoms and molecules.

ps:物质是由原子和分子组成的。

Matter课题; 事情; 问题; 事态; 当前的状况; 怎么了; 事关紧要; 要紧; 有重大影响

made of“make certain”的变体

atoms原子; atom的复数

molecules分子; molecule的复数

Water, for example, is the H2O molecule. 

This means that a molecule of water has 3 atoms. 

A water molecule has 2 hydrogen atoms and 1 oxygen atom.

Substances like sugar have many atoms in their molecules. 

A molecule of sugar has many atoms, including carbon, hydrogen and oxygen.

Exercises:

1.how many hydrogens atoms are in their water molecules?

A water molecule has 2 hydrogen atoms

Put the sentences into correct order:

Matter is made of atoms and molecules.Water, for example, is the H2O molecule. This means that a molecule of water has 3 atoms. A water molecule has 2 hydrogen atoms and 1 oxygen atom.

Matter is made of molecules, such as H20, which is the water molecule. 

Matter can be in one of three states: solid, liquid or gas. 

Water and ice are the same substance, but they are in different states. 

These states depend on the temperature of the molecules. 

When we heat a substance, the molecules move faster and try to take up more space. 

When we cool a substances, the molecules move more slowly. 

When we cool a substance to its freezing point, it becomes a solid. 

Exercises:

1.what happens when we heat a substance?

 the molecules move faster and try to take up more space.

2.these states ... on the temperature of the molecules.

depend

Fill in the blanks:

Water and ice are the same substance, but they are in different states. 

In a solid, the molecules move very little. 

Their positions are almost fixed. 

To be fixed means that their positions don’t change.

If we heat the molecules, they move faster and away from each other. 

The solid begins to melt, like ice cream on a hot day. 

Exercises:

1.how can we change a liquid into solid?

cool it down

Fill in the blanks:

To be fixed means that their positions don’t change.

Read and repeat the sentences:

1.Matter is made of atoms and molecules.

2.Water, for example, is the H2O molecule. 

3.to change a solid into a liquid, add heat.

4.A molecule of sugar has many atoms, including carbon, hydrogen and oxygen.

5.Water and ice are the same substance, but they are in different states. 

At a certain temperature, a solid begins to change into a liquid.

The temperature at which a solid changes into a liquid depends on the substance. 

For water, the solid begins to change into a liquid when its temperature rises to about 0 degree Celsius. 

For some substances, such as steel, the temperature at which it becomes a liquid is much higher. 

Steel often melts at around 1370 degrees Celsius.

Exercises:

1.At what temperature, does ice begin to melt?

above 0 degrees.

Fill in the blanks:

The temperature at which a solid changes into a liquid depends on the substance. 

If we continue to heat a liquid, the molecules move even faster. 

At a certain temperature, the liquid begins to change into a gas.

For water, the liquid begins to change into a gas at 100 degrees Celsius. 

That is the boiling point of water.

Exercises:

1.At what temperature, does water boil?

100 degrees Celsius.

Fill in the blanks:

1.At a certain temperature, the liquid begins to change into a gas.

Inside a star, such as our Sun, the temperature is very high. 

Everything inside the Sun is a gas. 

According to scientists, there are over 65 elements inside the Sun. 

These include oxygen and iron. 

Over 90 percent of the Sun is hydrogen gas.

Exercises:

1.what the temperature inside a star?

the temperature is very high

Fill in the blanks:

According to scientists, there are over 65 elements inside the Sun. 

Read and repeat the sentences:

1.That is the boiling point of water.

2.Over 90 percent of the Sun is hydrogen gas.

3.According to scientists, there are over 65 elements inside the Sun.

4.For water, the liquid begins to change into a gas at 100 degrees Celsius.