Chemical changes take place all around us.

化学变化就发生在我们的身边。

Unlike in baking, this chemical change releases heat and gives off light.

和烘焙不一样的是，这种化学变化释放了热量和光。

I hope you enjoyed learning about physical and chemical changes today.

希望你喜欢今天学习物理和化学变化的课程。

The circadian rhythm of a human being creates several physiological and chemical changes within the body.

人体的昼夜节律会在体内产生一些生理和化学变化。

After all, oxidation is responsible for a lot of chemical changes, like corrosion that breaks down metal.

毕竟，氧化是许多化学变化的原因，比如分解金属的腐蚀。

Perhaps most interesting, and most easily measured, is a chemical change in ground water before a quake.

也许最有趣、也最容易测量的，是地震前地下水发生的化学变化。

A strong blow to the head causes chemical changes within nerve cells that damage their structural proteins.

头部遭受的猛烈撞击会使得神经细胞发生化学变化，进而造成结构蛋白损伤。

It works by spotting chemical changes in fragments of genetic code that leak from tumors into the bloodstream.

其工作原理是寻找从肿瘤泄露到血液中的遗传密码片段的化学成分变化。

Chemical changes occur when the particles of two or more substances are rearranged to form a new substance.

化学变化发生时，两种或者两种以上物质微粒重新排列形成一种新的物质。

Look around and see if you can identify the physical and chemical changes around you!

看看周围，看看你是不是能不能发现身边的物理变化和化学变化吧！