States of Matter 物质状态

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

Water, for example, is the H2O molecule. 例如，水是H2O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 their 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. 一个糖分子有许多原子，包括碳、氢和氧。

Q：What is matter made of?  atoms and molecules. 物质是由什么构成的? 原子和分子。

Matter is made of molecules, such as H20, which is the water molecule. 物质是由分子组成的，比如水分子H20。

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. 当我们冷却某种物质时，分子运动得更慢。

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。

Q：What happens when we heat the substance? The molecules move faster and try to take up more space. 当我们加热物质时会发生什么？ 分子会加快移动速度并试图占据更多空间。

Q：What do the states of matter depend on? temperature. 物质的状态取决于什么? 温度。

In a solid, the molecules move very little. 在固体中，分子只有很小的移动。

Their positions are almost fixed.(R) 它们的位置几乎已经固定了。

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，它们会运动得更快并且远离彼此。

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

Q：How can we change a liquid into a solid？cool it down. 我们怎样把液体变成固体？冷却它。

Q：How can we change a solid into a liquid?  heat it up. 我们怎样把固体变成液体? 加热它。

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

At a certain temperature, the 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，比如钢，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。

Q：At what temperature does ice begin to melt?  above 0 degrees Celsius. 冰在什么温度开始融化?  0摄氏零度以上。

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 a (certain) 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.(R) 这是水的沸点。

Q：At what temperature does water boil?  100 degrees Celsius. 水在什么温度沸腾? 100摄氏度。

Inside a star, such as our Sun, the temperature is very high.(R) 在恒星内部，比如我们的太阳，温度是非常高的。

Everything inside the Sun is a gas.  太阳内部的一切都是气体。

According to (scientists), (there) are over 65 elements (inside) the Sun. 根据科学家的研究，太阳里有超过65种元素。

These include oxygen and iron. 其中包含氧气和铁元素。

Over 90 percent of the Sun is hydrogen gas. 太阳的90%以上是氢气。

Q：What is the only state of matter inside a star? Everything inside the Sun is a gas. 恒星内部只有什么物质状态？太阳内部的一切都是气体。

Q：What’s the temperature inside the star？the temperature is very high. 恒星内部的温度是多少? 温度非常高。

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