Why do ghostly lines show up in dry grass or crops?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do ghostly lines show up in dry grass or crops?

The Big Idea

Sometimes faint lines appear in dry grass or crops. They outline old buildings hidden underground! Archaeologists call them crop marks.

Buried Walls

Step one: Buried Walls. Buried stone walls or roads make the soil shallow above them. So plants dry out faster and turn yellow.

Buried Ditches

Step two: Buried Ditches. Buried ditches hold more water. So plants above them grow greener and taller.

From Above

Step three: From Above. From the air, these differences make faint lines called crop marks. They reveal outlines of old buildings and forts, and help archaeologists decide where to dig.

A Closer Look

Let's take a closer look! A buried wall is below. Plants above turn yellow. A buried ditch holds water. Plants above grow green.

Quick Facts

Quick facts! The lines show best during a dry summer. Drones and planes take photos of crop marks. Crop marks have revealed old forts and villages. Crop marks help archaeologists decide where to dig.

Think Like a Scientist

Now, think like a scientist! During a dry spell, look at a park's grass from a high window or hill. Look for lines or shapes. Are some patches greener or yellower? Draw what you see. What might be buried below?

Outro

Ghostly lines in dry grass or crops are crop marks. Buried walls make plants dry and yellow, while buried ditches make them greener, revealing outlines of old buildings from the air. Science is amazing! Keep asking questions! The more you look around, the more wonders you will find, so keep your eyes open! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!