Natural structures

Bis forBubble

Bubbles are a pocket of air surrounded by a thin coating of something else. Bubbles are usually made from blowing air into soapy water. They are round, and float through the air. There are pretty colours on the surface of the bubble.

jennifer.zhou / CC BY-SA

Bis forBurrow

Natural structures

A burrow is a hole in the ground that animals like foxes and badgers dig as homes for themselves.
Burrowing can also be used as a verb, as in "the rabbit was burrowing into the side of the hill".

Lee Haywood / CC BY-SA

Cis forCocoon

Natural structures, Containers

A cocoon is a place a caterpillar makes for itself. The caterpillar goes to sleep inside it for some time and then comes out as a butterfly.

Renee Grayson / CC BY-SA

Nis forNest

Natural structures

Birds build nests to lay their eggs in. Nests are usually made from sticks and lined with feathers and anything soft that the bird can find, such as threads from clothes and even cobwebs. Some birds make nests out of mud.

Nils Söderman / Public Domain

Sis forShell

Natural structures, Body parts

A shell is the hard outside coating found on many animals. Snails have shells that form a spiral that was built up as the snail grew bigger. crabs and turtles have a hard shell that perfectly fits the animal inside. Most animals that have shells can hide inside them if they are scared.

Karunakar Rayker / CC BY-SA

Wis forWeb

Natural structures

Spiders spin webs between twigs (or anything) to catch insects in. Webs are sticky, so insects that fly into the web get stuck. The spider sits on the web and feels for the vibrations of a struggling insect with its feet, and then comes over to wrap it up in more webbing and eat it.

Jan Smith / CC BY-SA