What is a cloud?

The following is by contributor Catherine Way of Indirect Observations.
In my part of the world (subtropical Northern Australia) at the moment, the weather is changing from cool, sunny dry season weather to hot, sticky, rainy wet season weather.  We call this time of year the ‘build-up’  The humidity builds up making it hot and sticky.  The build-up will eventually be broken by the arrival of monsoon rains.

The build-up means that clouds have returned to our skies – everything from wispy, barely there, white streaks to tall, dramatic sculptures.  We have also had many foggy mornings – my children tell me  this is ‘the clouds touching the ground.’  We have even had the odd dark, ominous looking cloud that made us talk about the possibility of rain.

It seemed a good time to do some cloud and weather related investigations.  The variable weather of Autumn or Spring in more temperate parts of the world also brings variable weather, making this an excellent time to explore weather with your children.

What is a cloud?

A cloud is a collection of tiny water or ice droplets.  All air contains water vapour.  Close to the ground, the air is warm and water is an invisible gas.  As the air rises it cools and cannot hold as much water vapour, so water begins to condense around tiny dust particles in the air.  When billions of water droplets have condensed we will see a cloud.

Clouds are white because they reflect all light.   If the cloud gets thick enough or high enough it begins to block some of the sunlight and the cloud will appear dark or grey.

Fog is formed when warm moist air is blown into a region over much cooler ground.  As the air cools, moisture condenses from the air forming fog.

Identifying cloud types

There are many different types of clouds.  Clouds are grouped according the the way they look – are there clumps, layers or streaks? – and according to how high they are – are they low, mid level or high in the sky?  The types of clouds in the sky can tell us about the type of weather we can expect in the near future.

Some examples of the types of clouds are:
High, wispy, white clouds are called cirrus and mean good weather.
Grey, heavy clouds covering most of the sky at low or mid levels are called stratocumulus and mean a change in the weather: either rain or snow is likely or the weather is clearing.
Tall, dark clouds are called cumulonimbus and show us that thunderstorms are on the way.
Low, flat layers of clouds blanketing the sky are called stratus and indicate drizzle and an overcast day.
Fluffy, low clouds on a sunny day are called cumulus and usually mean fair weather.
Thick, puffy clouds blanketing the sky at mid-heights are called altocumulus and indicate rain or snow is likely.

There are other types of clouds as well. You can read more and see pictures of the clouds at Weather Wiz Kids.

Identifying clouds is fascinating, although it can be quite difficult.  If you and your children would like to try identifying clouds, you can print and construct a cloud finder wheel to help you.

Create a cloud in a bottle

This simple experiment will help your children to understand the elements needed for clouds to form.

You Will Need:
  • a clear plastic bottle
  •  matches
  •  warm water

Put a little warm water in the bottom of the bottle and put the lid on.  As the warm water evaporates, it adds water vapour to the air inside the bottle.

Take the cap off the bottle.  Light a match and hold it in the opening of the bottle.  Drop the match into the bottle and quickly put the lid back on the bottle, trapping the smoke inside.

We now have the two ingredients needed to make a cloud in the bottle – water vapour and smoke particles in the air.

Slowly squeeze the bottle and release.  A cloud should appear when you release the bottle.  Squeezing the bottle causes the air pressure in the bottle to increase.  When you release the pressure, a cloud forms (this is equivalent to the change in air pressure in nature as air rises and cools).

Model a thunderstorm

To help children visualize how a thunderstorm forms try this experiment from Weather Wiz Kids

You Will Need:

  • a plastic container
  • red food colouring
  • ice cubes made with blue food colouring

Fill the container two-thirds full with warm water.  Let the water sit for a minute.

Place a blue ice cube at one end of the container.  Add 3 drops of red food colouring to the other end of the container.

Watch what happens.  You have modelled a thunderstorm by showing what happens when a cold air mass (the blue water) meets a warm unstable air mass (the red water).

When you look from the left photo, you can see the colours spreading out in the water.  But when you look through the side of the container in the right photo, it is clear that they are not mixing.  The cold, blue water has fallen to the bottom of the container beneath a layer of the warmer, red water (the storm clouds).

When we did this experiment, one of my son’s first reactions was to want to put his hands in and mix the water.  This gave him an additional sensory understanding of the experiment, as he discovered that the water was cold at the bottom of the tub and warmer at the top.

Visit Weather Wiz Kids for the full explanation.

Tracking the Weather

If your children are very interested in learning about the weather you may want to track the weather for a while.

Here are some helpful links:

Weather influences our lives in many ways, including influencing our decisions about what to do and what to wear. This makes weather a topic of enormous fascination and importance for children.

I encourage you to get outside and spend some time talking and thinking about the weather with your children this month.

What is your children’s favourite type of weather?

About Catherine

Catherine Way is mum to two boys living in North Australia. They read lots, run lots, love to learn new things and are good at finding fun and mischief. Catherine blogs about her family adventures and passion for lifelong learning at Indirect Observations.

Online Knitting Class
Delightful kids' crafts delivered to your door!  See sample crates>>


  1. My daughter is a little young for the thunderstorm experiment but I think she’ll love the idea of making a cloud. She likes all types of weather. We go out on the front porch and watch storms roll in. We stomp around in muddy puddles after rainstorms. And we love to make our way outside in the crispy fall morning air.
    Steph´s latest post: When you’re THAT mom

  2. Ooooo. . . I did these experiments with my older kids, but I don’t think my younger ones have ever done them. You’re right, now is a great time to do a little weather study, especially since we’re just finishing up some projects about caves. Time for a change of subject. Thanks for the websites, especially!
    Jen@anothergranolamom´s latest post: Apple Pan Dowdy


  1. […] Activity #32 – watch the clouds (and do some simple weather experiments) […]