There are many ways you can stick something together. There are many natural kinds of glue. Egg is one of them. You can brush a beaten egg on two pieces of pastry and it will hold them together. It is quite a good glue, as you will find if you spill some on your clothes and then try to wash it off after it has dried.

Another natural glue is flour and water. This is used to stick paper together and make papier-mâché.

Starch (the white liquid that comes out of potatoes and rice, for example) is a common glue.

There are also many glues that are made from oil. Many of these are very powerful.

Some glues come in liquids, while others are a kind of a solid and are fixed to a strip of plastic. Adhesive tape is like this. The glue does not stick to shiny things like the back of the tape, so it can be wound in a roll, but it will stick to rougher surfaces like paper. Parcel tape and Duct tape are similar.

Some glues are so powerful they can be used to stick parts of cars and aircraft together.