Condensation station

• It’s up to you when you make your cloud – we think it’s best to learn about the names first.
• You may want to run this activity over two sessions. 
• You may want to step outside your meeting place and do some cloud-watching if you're able to, so make sure everyone brings suitable clothing. 
• You may want to show everyone some pictures of different types of clouds to help you explain the differences between them and how they're formed.

Learn about clouds

1. Gather everyone in a circle. Explain that today you're going to find out more about clouds. 
2. Ask if anyone knows anything about clouds that they'd like to share.
3. Clouds are one of nature's most consistently visible wonders and can also tell us a lot about what is going on up in the atmosphere.
4. Explain that clouds form when water vapour that's evaporated into the air cools down and condenses, which is when the water turns back into liquid. This water in the sky forms clouds. The water droplets form more easily if they have something to stick to, like dust or smoke.

Naming clouds

1. Tell everyone that cloud names often combine the type of cloud with its height. ‘Alto’ is used to describe mid-level clouds and ‘Cirro’ is used to describe  high clouds.
2. Where these names are combined, we can often build up an idea of that cloud's character. For example, if we combine nimbus and stratus we get 'nimbostratus' - a cloud which is flat and layered and has the potential for rain.
3. Most of our names for clouds come from Latin and are usually a combination of the following prefixes and suffixes:

• Stratus/strato: flat/layered and smooth
• Cumulus/cumulo: heaped up/puffy, like cauliflower
• Cirrus/cirro: high up/wispy
• Alto: medium level
• Nimbus/Nimbo: rain-bearing cloud

The 10 main groups of clouds

1. The World Meteorological Organization (WMO) have 10 main groups of clouds, called genera.
2. These 10 groups of clouds divided into three levels - cloud low (CL), cloud medium (CM) and cloud high (CH).
3. High clouds are usually 20,000 ft or above over the UK, and the cloud types are Cirrus, Cirrocumulus and Cirrostratus.
4. Medium clouds are usually between 6,500 and 20,000 ft over the UK. The cloud types are Altocumulus, Altostratus and Nimbostratus.
5. Low clouds are usually between usually below 6,500 ft over the UK. The cloud types are Stratocumulus, Stratus, Cumulus and Cumulonimbus.
6. There are many possible variations in the shape of clouds. 

What do the main clouds look like?

1. There are lots of different shaped clouds. Here's what the main 10 groups of clouds look like in the sky. 
2. You could print out or write out these descriptions and have a different person read each one. You could also write or print out the cloud name and the description separately, then cut them out and have it as a matching pairs challenge in small groups. 

High clouds

All high clouds are a type of cirrus, a common cloud that can be seen at any time of the year.

1. Cirrus: Cirrus clouds are short, detached, hair-like clouds found at high altitudes. These delicate clouds are wispy, with a silky sheen, or look like tufts of hair. In the daytime, they are whiter than any other cloud in the sky. While the Sun is setting or rising, these clouds may take on the colours of the sunset.
2. Cirrocumulus: Cirrocumulus is a relatively rare cloud. They're made up of lots of small white clouds called cloudlets, which are usually grouped together at high levels. The little cloudlets are regularly spaced, often arranged as ripples in the sky which may resemble honeycomb or look like the scaly skin of a fish. These clouds are made up almost entirely from ice crystals.  
3. Cirrostratus: Cirrostratus are transparent high clouds. They cover large areas of the sky. They sometimes produce white or coloured rings around the Sun or Moon. They can span thousands of miles, can be smooth or fibrous (which is when a cloud looks like lots of threads of hair). Cirrostratus clouds often have with cirrus clouds near their edges. Shadows will normally still be cast by the Sun when shining through cirrostratus clouds.

Medium clouds

1. Altocumulus: Altocumulus clouds are small mid-level layers or patches of clouds, called cloudlets. The cloudlets most commonly exist in the shape of rounded clumps. There are many varieties of altocumulus, so they can appear in a range of shapes. Altocumulus clouds are generally associated with settled weather and will normally appear white or grey with shading.
2. Altostratus: Altostratus are large mid-level sheets of thin cloud. Usually composed of a mixture of water droplets and ice crystals, they are thin enough in parts to allow you to see the Sun weakly through the cloud. They are often spread over a very large area and are typically featureless.
3. Nimbostratus: Nimbostratus clouds are dark, grey, featureless layers of cloud, thick enough to block out the Sun. Producing persistent rain, these clouds are often associated with frontal systems provided by mid-latitude cyclones. These are probably the least picturesque of all the main cloud types.

Low clouds

1. Stratocumulus: Stratocumulus cloud consists of large, rounded masses of flat, hazy, featureless clouds that form groups, lines or waves. They vary in colour from bright white to dark grey. They're the most common clouds on earth recognised by their well-defined base/bottom edge. Some parts are often darker than others. They usually have gaps between them, but they can also be joined together.
2. Stratus: Stratus clouds tend to be featureless, low altitude clouds. They cover the sky in a blanket of white or grey. Stratus clouds have a fairly uniform grey or white colour. Often creating dull, overcast days, they can persist for long periods of time. They're the lowest-lying cloud type. They sometimes appear at Earth's surface in the form of mist or fog.
3. Cumulus: Cumulus clouds are fluffy and cauliflower-shaped. They’re one of the most common and distinctive types of cloud. Cumulus clouds are detached from other clouds, being individual, and are usually spotted in fair weather conditions. The tops of these clouds have brilliant white tufts when lit by the Sun, although their base is usually relatively dark.
4. Cumulonimbus: Cumulonimbus clouds are menacing looking multi-level clouds, extending high into the sky in towers or plumes. More commonly known as thunderclouds, cumulonimbus is the only cloud type that can produce hail, thunder and lightning. The base of the cloud is often flat, with a very dark wall-like feature hanging underneath. They may only lie a few hundred feet above the Earth's surface. 

Practising the cloud names

1. Everyone should step outside, or find a window, and try to name any clouds they can see. 
2. Everyone should keep practising the new cloud words until they’re confident about what they mean.
3. You could play a game of bingo with the cloud names and read out the descriptions. Everyone would just need a piece of paper and a pen to draw a grid on, then write in their choice of cloud names. 

Create some cotton wool clouds

1. Everyone should take some card, cotton wool, glue and any other craft materials. 
2. People should use the cotton wool to make different clouds on their card and label them. They should try to make as many different types of clouds as they can. This is a great chance to practise using the scientific words!

Make your cloud

1. Everyone should get into their small groups and each small group should work with an adult.
2. Each group needs a 2L empty bottle with a cap, some matches, and a jug of warm water.
3. One person should remove any labels on their bottle.
4. Next pour a few centimetres of warm water into the bottle. They should screw the lid back on tightly and shake the bottle, so the inside’s coated with water.
5. When the group's ready, take the lid back of the bottle. 
6. The supervising adult in each group should carefully light a match. They should let it burn most of the way, then blow it out and quickly drop it into the bottle. This is where working together comes in handy – someone can focus on opening and closing the bottle while the adult’s blowing out the match and dropping it in the bottle.
7. Someone in the group should squeeze the bottle as hard as they can. They could try putting the bottle on the floor and standing on it to squeeze it harder. However, no one should jump on it – it might make the bottle burst.
8. When the bottle's been squeezed, everyone should let go of the bottle and watch a cloud start to form.
9. Someone should hold the bottle sideways, open it and gently squeeze the cloud out. Watch the cloud float away!

Clouds and pilots

1. Ask everyone whether they think clouds affect planes and pilots.
2. Explain that planes cope well with clouds. Most of the time, pilots use autopilot (a system used to control the path of an aircraft) or digital maps when visibility’s reduced. Pilots may sometimes navigate differently around big clouds, especially cumulonimbus clouds, because they can cause storms and turbulence. Navigating around them makes the flight smoother for passengers.