States of Matter

Matter is made of atoms and molecules.物质是由原子和分子构成的。

Water, for example, is the H2O molecule. （分子）

This means that a molecule of water has 3 atoms. 这意味着一个水分子有3个原子。

A water molecule has 2 hydrogen atoms and 1 oxygen atom.一个水分子有两个氢原子和一个氧原子。

Substances like sugar have many atoms in the molecules. 像糖这样的物质分子中有许多原子。

A molecule of sugar has many atoms, including carbon, hydrogen and oxygen.糖分子有许多原子，包括碳、氢和氧。

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

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

物质可以是三种状态之一，固态、液态或气态。

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

 水和冰是同一种物质，但它们处于不同的状态。

These states depend on the temperature of the molecules. 这些状态取决于分子的温度。

When we heat a substance, the molecules move faster and try to take up more space. 当我们加热一种物质时，分子运动得更快，并试图占据更多的空间。

When we cool a substance, the molecules move more slowly. 当我们加热一种物质时，分子运动得更快，并试图占据更多的空间。

When we cool a substance to its freezing point, it becomes a solid. 当我们把一种物质冷却到冰点时，它就变成固体。

What do the states of matter depend on? temperature物质的状态依赖于什么?温度

In a solid, the molecules move very little. 在固体中，分子几乎不动。

Their positions are almost fixed. 它们的位置几乎是固定的。

To be fixed means that their positions don't change.被固定意味着他们的位置不会改变。

If we heat the molecules, they move faster and away from each other. 如果我们加热分子，它们会运动得更快，彼此远离。

The solid begins to melt, like ice cream on a hot day. 固体开始融化，就像热天的冰淇淋。

To change a solid into a liquid, add heat.要把固体变成液体，加热。

At a certain temperature, a solid begins to change into a liquid.在一定的温度下，固体开始变成液体。

The temperature at which a solid changes into a liquid depends on the substances. 固体变成液体的温度取决于这些物质。

For water, the solid begins to change into a liquid when its temperature rises to above 0 degree Celsius. 对于水来说，当温度上升到0摄氏度以上时，固体就开始变成液体。

For some substances, such as steel, the temperature at which it becomes a liquid is much higher. 对于某些物质，如钢，它变成液体的温度要高得多。

Steel often melts at around 1370 degrees Celsius.钢通常在1370摄氏度左右熔化。

At what temperature does ice begin to melt? below 0 degrees Celsius冰在什么温度开始融化?摄氏零度以下

If we continue to heat a liquid, the molecules move even faster. 如果我们继续加热液体，分子运动得更快。

At acertain temperature, the liquid begins to change into a gas.在一定的温度下，液体开始变成气体。

For water, the liquid begins to change into a gas at 100 degrees Celsius. 对于水来说，液体在100摄氏度时开始变成气体。

That is the boiling point of water.这是水的沸点。

At what temperature does water boil? 100 degrees Celsius

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 an iron.

Over 90 percent of the sun is hydrogen gas.

Test Results

Yesterday there was an important science test. 

Lisa, Tom and 20 other classmates took the test. 

The test was about the states of matter and how they are different. 

There were 25 questions on the test, and they had 45 minutes to take it. 

Here are some of the test results.

Two students got perfect scores. 

The lowest score was 68 out of a hundred. 

The average score was 86.3. 

Eleven students scored higher than average. 

Eleven students had below average scores.

Tom missed two questions on the test, so his score was 92. 

His score was the eighth highest in the class. 

Lisa missed two and a half questions, so her score was 90. 

Her score was the tenth highest score. 

Her score was 4 points higher than the average score. 

Lisa was disappointed with her test results. 

She studied hard for the test, but she still didn’t do well. 

As a result, she plans to study harder for the next test. 

The next test will be in about two weeks. 

Tom was surprised and happy with his test results. 

He didn’t study hard, so his result was better than he expected. 

He was also happy that he did better than Lisa did.