岩层与相对年代

理解岩石层（地层）是按顺序形成的：最古老的岩层在底部，最新的岩层在顶部；在越深的岩层中发现的化石越古老——这就是相对年代测定的原理。

Understand that rock layers (strata) form in sequence with the oldest at the bottom and the youngest at the top, and that fossils found in deeper layers are older — this is the principle of relative dating

学习证据 / Evidence

• 解释沉积岩是一层层形成的，最古老的岩层在底部
• 利用岩层示意图，根据化石所在的位置判断哪个化石更古老
• 把相对年代测定解释为：通过比较某物在岩层中的位置来推断它的年龄

• Explain that sedimentary rock forms in layers with the oldest at the bottom
• Use a diagram of rock strata to determine which fossil is older based on its position
• Define relative dating as working out the age of something by comparing its position in rock layers

评估问题 / Assessment

如果{{name}}看到一座有岩层的悬崖，他们能不能解释底部的岩层最古老，越深的地方发现的化石生活年代越久远？

If {{name}} saw a cliff with layers of rock, could they explain that the bottom layers are the oldest and that fossils found deeper down lived longer ago?