1. Make your own balloon bacterium
Balloon Bugs
Make your own balloon bacterium

2. What are Bacteria Bacteria are living organisms
They are so small you need a microscope to see them
They come in different shapes and sizes
They can be found everywhere!
Bacteria are a type of microbe. They are single-celled organisms that can grow and divide rapidly in the right conditions.
Bacteria can only be seen using a microscope. They can be all sorts of shapes and sizes, and can be found in pretty much any environment you can think of, including Antarctic sea ice and deep sea vents.

3. How big are bacteria?
Bacteria are tiny! Millions can fit on a single pin head.
Bacteria are microscopic. The largest bacteria are around 10 micrometres. That is 10 millionths of a metre, or one thousandth of a centimetre, or one hundredth of a millimetre.
This image offers a sense of scale by zooming in on bacteria found on the head of a pin.
A useful video that can be used to give an idea of the size of bacteria can be found at

4. What shape are bacteria?
There are three main shapes of bacteria
Bacteria can be divided into groups by their shape. Cocci are shaped like spheres or balls, bacilli are shaped like rods, and spirochaetes are shaped like a spiral.
To help the students visualise this you can use food items. For example, cocci can be represented using M&Ms or Maltesers, bacilli can be represented using Tic Tacs, and spirochaetes can be represented using spiral pasta.
SPHERES
(cocci)
e.g. Staphylococcus sp.
RODS
(bacilli)
e.g. Citrobacter sp.
SPIRALS
(spirochaetes)
e.g. Campylobacter sp.

5. How do bacteria move?
Some bacteria have special structures that help them move. These are called flagella.
flagella
Some bacteria can move around their environment using a special tail-like structure called a flagellum. Some bacteria, like Campylobacter have just one flagellum to help them move (see left image). Others like Salmonella Typhimurium have several flagella to help them move around.
flagellum