55 Impact Craters-Mid

Impact Craters FOCUS Question How do impact craters form on Earth's surface?

撞击坑焦点问题撞击坑是如何在地球表面形成的?

What Is a Crater A crater is a round dent in Earth's surface. Craters can be as small as a truck tire. Most are bigger. The largest known crater is in South Africa. It is the size of Maine!

什么是陨石坑陨石坑是地球表面的圆形凹陷。 弹坑可以像卡车轮胎那么小。 大多数都更大。已知最大的陨石坑在南非。 它有缅因州那么大!

What Causes Craters? Some craters. form when a volcano erupts Others form when rocks from space hit Earth. These rocks are called meteors. Meteors can crash into Earth so fast and hard that they leave a hole. These holes are called impact craters. Earth has over 180 known impact craters! Word Wise A meteor is also called a shooting star. It looks like a streak of light that flashes across the night sky. Once a meteor lands on Earth we call it a meteorite.

是什么导致了陨石坑?一些陨石坑。 另一些则形成于来自太空的岩石撞击地球时。 这些岩石被称为流星。 流星撞击地球的速度之快、力度之大，会留下一个洞。 这些洞被称为撞击坑。 地球上有超过180个已知的陨石坑!流星也被称为流星。 它看起来就像一道划过夜空的光。 一旦一颗流星落在地球上，我们就称之为陨石。

Kinds of Craters There are two kinds of impact craters. A simple crater is shaped like a smooth bowl. It is usually a shallow dent in the ground Complex craters are usually much larger and deeper. They are rough and have bumps and valleys.

陨石坑的种类有两种。 一个简单的陨石坑形状像一个光滑的碗。 复杂的陨石坑通常要大得多，也深得多。 它们很粗糙，有凹凸不平的地方。

Parts of a Crater Craters have three main parts. Each crater has a floor, a wall, and a rim. These parts are easier to see on a simple crater.

火山口有三个主要部分。 每个陨石坑都有地板、墙壁和边缘。 这些部分在简单的陨石坑上更容易看到。

A Young Crater Barringer Crater in Arizona is very young for a crater. It formed less than 50,000 years ago. It is also a simple crater. It is 1 kilometer (3/4 mi.) across. Math Moment How much wider is South Africa's Vredefort Crater than Arizona's Barringer Crater?

亚利桑那州的巴林杰陨石坑是一个非常年轻的陨石坑。 它形成于不到5万年前。 它也是一个简单的陨石坑。 它有1公里(3/4英里)宽。 南非的弗里德堡陨石坑比亚利桑那州的巴林杰陨石坑宽多少?