: Learning

If you are visiting St. Fagans this month you will notice an army of gardeners and volunteers marching around the gardens with wheelbarrows full of organic matter to condition the soil of our beautiful gardens. As winter comes to an end, spring arrives with a promise of growth. This is a crucial moment in the gardening calendar to prepare for the warmer months ahead. 

Because of the over-emittance of greenhouse gases, the Earth’s surface temperature is increasing rapidly. We are noticing summer months that are hotter and drier than ever, only last year we witnessed temperatures around 40°C in some areas of the UK. The excessive heat and prolonged drought have devastating effects on our local flora and fauna. 

One of the most important tasks for this month is to mulch the soil by adding a layer of organic matter to the soil surface. Mulching brings numerous benefits to plants including moisture retention in periods of drought, weed suppression, improvement of soil structure and fertility, reducing the need for artificial fertilisers, prevention of soil erosion, and encouragement of beneficial organisms such as earthworms, soil bacteria and fungi. Additionally, it attracts wildlife to our gardens, one of my favourite memories is of being followed by Robins as we mulch the garden in spring. They patiently wait for a feast of earthworms, while gifting us with their beautiful bird song announcing the arrival of spring. 

There are many different types of mulching materials and each with their own benefits and uses. Most of our gardens are mulched with well-rotted farmyard manure sourced from Llwyn-yr-eos farm in St. Fagans and from a local farmer. The manure is gradually incorporated into the soil by the activity of earthworms and other microorganisms, which improves the soil structure and supplies the plants with nutrients. This nitrogen rich material is ideal to be used on herbaceous borders, vegetable beds, roses and newly planted trees and shrubs.

However not all plants like nutrient rich mulches, plants that are adapted to growing in hot and dry conditions often do not cope well with excessive moisture and high fertility. For example, in the Herb Garden where we have Mediterranean plants such as lavender, rosemary, sage and thyme we have opted for mulching the beds with gravel. This is an inorganic material that does not break down; therefore it does not release nutrients to the soil. In addition, gravel is great at promoting good drainage, suppressing weeds, and adding aesthetic value to the garden.  

This year we are trying new methods of mulching as a sustainable way to utilise the maximum of our local resources. We have started using raw wool provided by the Llwyn-yr-Eos farm to mulch the vines in the greenhouse. This will help with water conservation and prevention of weeds. Besides the wool fleece degrades slowly releasing nutrients into the soil and feeding the vines. Another advantage is that wool can help retain heat during colder months, keeping the root of the vines warm in winter. 

In March we cut back the ornamental grasses and perennials of the Dutch garden and a large amount of material usually ends up in the compost heap. This year we decided to skip this process and instead we added the dried grass clippings directly to the surface of the pumpkin patch. We have sprinkled a fine layer of manure on top to weigh down the grasses and prevent them from blowing in the wind. This will also aid the process of decomposition by introducing nitrogen to this carbon rich material.  While the farmers make hay for a rainy day, the gardeners mulch with hay for a hotter day.

When choosing mulches or growing mediums for your garden, prefer materials from sustainable and local sources in order reduce the carbon footprint from transportation. It is also important to avoid peat-based composts at all costs. The extraction of peat has a negative impact in the environment, it destroys the natural habitat of many species that live in peatlands, besides it releases tons of carbon dioxide into the atmosphere contributing to the greenhouse effect. 
For the home gardener the most sustainable and cost-effective option is to mulch using homemade compost or leaf mould. Why not try making your own compost using kitchen and garden waste? You will be surprised at the benefits you can reap from your compost heap. 

Hello Bulb Buddies,

Thank you for the comments and observations you sent in with last week’s weather readings. I’m expecting that some of Friday’s weather comments will mention snow, as many areas across the UK will have woken up to snow and ice this morning. I thought this might be a good time to look at how Meteorologists (weather scientists) measure snow. 

It is a lot trickier to measure the amount of snow that falls than it is to measure the amount of rain. This is because snow misbehaves! Snow is often blown by the wind into drifts, which causes some areas of deep snow and less snow in the areas around it. Because the snow fall is uneven the measurements from these places will be wrong. This is why we have to measure snow on flat surfaces, in the open and away from areas where drifts happen. Snow also likes to play games with Meteorologists who want to measure it, it melts into water and re-freezes into ice. This means that the snow measured on the ground isn’t always the same as the amount of snow that has fallen. Another problem is that new snow settles on old snow, so it is difficult to tell how much snow has fallen in one day from the snow that fell the day before.

Meteorologists have to take all these tricks the snow plays, and work around them to discover how much snow has fallen. They look at snow fall (the amount of snow that falls in one day) and snow depth (how deep the total snow level is, old snow and new snow). One way that Meteorologists measure snow fall is to use a piece of ply wood. They place the wood in an open location away from areas where snow drifts occur, and measure the snow on the board at 6hr intervals, clearing the snow from the board each time they measure it. This means they are only measuring the snow from that day, which will tell them how much snow has fallen on that day in that area.

Snow fall can also be measured in its melted state, as water. This means that you can use your rain gauge to measure the water equivalent of snow fall. If you only get a bit of snow then it should melt in your rain gauge anyway. But if you get a lot of snow, take your rain gauge inside to the warm and wait for the snow to melt into water. Then measure the water in the same way as you have done each week and report this as rain fall in your weather logs. 

If you have snow and enough time for an extra experiment – why not have a go at measuring snow depth? To do this all you need is a ruler (also known as a snow stick!). Place the snow stick into the snow until it touches the surface underneath and read the depth of the snow. Take these measurements from flat surfaces (benches work well) in open areas and away from snow drifts. You need to take at least three separate measurements to work out the average snow depth in your area. You work out the average measurement by adding the different readings together and dividing them by the number of measurements. So, if I measured the snow depth of three surfaces at 7cm, 9cm and 6cm, I would add these together (7+9+6 =22) and divide that by three, because there are three readings (22÷3=7.33). So, 7.33cm would be my average reading for snow depth on that date. 

Weather stations such as the MET Office have come up with new ways of measuring snow depth, using new technologies. The picture on the right shows one of the MET Offices snow stations. These use laser sensors to measure how deep the snow is on the flat surface placed below it. This means that Meteorologists can collect readings from all over the country at the push of a button, which is far more reliable and a lot easier than sending people out into the cold with snow sticks! The map on the right shows how many snow stations the MET office has and where these are, is there one close to you? 

If you have snow and measure the snow fall with your rain gauge or the snow depth with a snow stick, then please tell me in the ‘comments’ section when you are logging your weekly records. I would be very interested to know what the snow depth is compared to the snow fall collected in your rain gauge.

Keep up the good work Bulb Buddies, 

Professor Plant

Hello Bulb Buddies,

Thank you to all schools who have shared their weather data so far. Remember to contact me if you need any help with this. All schools that enter data to the website will receive prizes at the end of the project, including super scientist pencils and certificates!

As spring approaches, I thought we could look at the changing seasons. There are four seasons in the year. Spring, summer, autumn and winter. In the UK, spring begins in March. When in March depends on which definition you use. The Meteorological definition sees Spring start on 1 March and the Astronomical definition sees it start on 20 March (the Spring Equinox). Spring is when most flowers bloom, the weather gets steadily warmer, and many animals have their young. Lambs in the fields are a good sign that spring has arrived, why not follow the Lamb Cam at St Fagans National Museum of History to see how many lambs are born there!

The summer comes in full force from June to September, and this is when we have the warmest weather and the longest daylight hours. Luckily for you, it’s also when you get your longest school holidays!

Autumn takes hold from late September, and this is when the days become shorter and the weather begins to get colder. This is when the leaves change colour from greens to oranges, reds and browns and fall from the trees. And, when animals like squirrels hoard food for the long winter ahead. Winter arrives again in December, and stays until mid-March.

Do you know why we get seasons? What causes the weather to change so dramatically throughout the year? Well, it’s because the Earth is turning around the Sun at an angle. The picture to the right shows the earth in relation to the sun. The earth turns (rotates) on its axis (imagine a line joining the North and South poles) as it moves around (orbits) the Sun.

It takes the Earth 365 days to travel once around the sun. The length of a planets year is the time it takes for it to complete one orbit of its star. So a year on Earth is measured as the passing of 365 days. 

The picture to the right shows the Earth’s rotation around the Sun. The axis is shown by the white line at the North and South poles. You can see that the axis (white line) is at a different angle to the Earth’s orbit (shown by the white arrows). This means that each day we are at a slightly different angle to the Sun than we were the day before. This is what causes a difference in the number of daylight hours we get. Fewer daylight hours (winter) means less light and heat, making this time of the year colder. More daylight hours (summer) means more light and heat, which makes it warmer!

Many of you have noticed that temperature increases throughout the morning, and decreases in the late afternoon. This is because the heat from the sun gradually warms our surroundings throughout the day. Materials and living things absorb this energy, and become warmer themselves, heating the air around them. The sun is at its highest point around noon, so this is when the earth gets the most light and heat energy from the sun. In the afternoon the heat and light from the sun gradually decreases. However, the materials and living things around you will continue to radiate heat, gradually cooling throughout the afternoon and evening. This is why the temperature is often higher between 2-3pm than it is at midday. This is also why temperatures are lower in winter than they are in summer, because the days are shorter and as such our surroundings receive less heat and light energy from the sun.  

The UK is in what is known as the ‘North hemisphere’, this means we are closer to the North Pole than the South Pole. Notice that in the picture the North pole (the white line pointing up) is leaning towards the Sun in summer and away from the sun in winter. This angle is what causes the change in daylight hours as the Earth orbits the sun over the course of the year.

Other countries experience the changes in daylight hours at different times of the year. In Australia it is summer in December! And in Iceland they have continuous sunlight for days in a row in the summer and darkness for as long in the winter! Imagine having sunlight at midnight!

Keep up the good work Bulb Buddies,

Professor Plant

The MET Office have issued weather warnings for fog for large parts of the UK today. Fog is dangerous when travelling because it causes poor visibility. Have you walked in a thick fog before? I’ve walked into a fog where I could only see about a foot to either side of me. It was thrilling, but I was on a long, even, mostly empty beach at the time. I wouldn’t have liked to be crossing roads or surrounded by obstacles I couldn’t see. 

Fog is made of water droplets smaller than rain drops. Some parts of the world use nets designed to capture the water droplets of fog, which provides a supply of water in areas that don’t see much rain. Some places call this ‘sky fishing’ or ‘stealing from the sky’. How much water do you think can be collected from fog? The MET Office website states that ‘if you were to fill an Olympic sized swimming pool with fog and then somehow condense it, you would be left with around 1.25 litres of water (or just over 2 pints).’ 

Do you know the difference between mist and fog? It’s visibility! The Met Office states that ‘If you can see more than 1,000 metres it's called mist, but if it is thicker and the visibility drops below 1,000 metres it's called fog.’ Mist and fog are both formed from water droplets collecting in the air, but mist is less dense (meaning an Olympic sized pool full of mist would provide less water when condensed) this means it can be seen through easier and is less likely to stick around for a long time. 

Fog can also be described as a cloud forming at ground level. This is because fog and clouds form in the same way. They are the result of warm, moist air being cooled. Water vapour in the air cools to form water droplets. For example, think about how the water vapour from a hot shower, clings to the cool glass of a mirror as condensation. Or, how on a cold day your breath forms a mist when you exhale, as your warm breath mixes with the cold air. Clouds form when warm, moist air meets with cooler air flows. Fog often forms when warm, moist air is cooled by cold surfaces. For this reason, fog is more common in autumn and winter when the ground is coldest. Except for coastal fog, which is more common when warm, moist summer air meets the cold surface of the sea. 

Water droplets in fog cause poor visibility by reflecting light, which can distort shapes and make it difficult to judge distances. The MET Office refers to thick fog when visibility is below 180m and dense fog when it’s below 50m (that’s the length of the Olympic sized pool we’ve been talking about!). It’s interesting to note that thicker fogs often form in industrial areas. This is because water droplets cling to tiny particles in the air. At the coast the water usually attaches to salt particles in the air. In industrial areas it’s often particles of air pollution that the water collects around. This means that industrial areas (which are usually the areas of highest air pollution) are more likely to see thicker fogs, because there are more particles in the air for the water to cling to. 

Fog that mixes with air pollution is often called smog (smoke fog). Smog can turn the sky green, yellow, red, brown, black or grey. It’s been a problem since the onset of the Industrial Revolution in the late 1700’s, which saw an increase in coal burning for industry (for example to fuel factories and steam trains). In December 1952 London saw what become known as ‘The Great Smog’, during which weather conditions trapped the smoke from coal fires and produced ideal conditions for the formation of a dense fog. Combined, this caused poor air quality that was extremely dangerous. The Clean Air Acts of 1956 and 1968 were a direct result of this, reducing emissions of black smoke. As a result, fewer smogs were reported in the UK in the following decades. 

However, since then something known as Photochemical smog (or summer fog) has become more common, especially in largely populated industrial cities with warm climates. This forms when sunlight reacts with pollution particles in the air (nitrogen oxides from car exhausts or coal burning and volatile organic compounds from gasoline, cleaning products and household aerosols). Photochemical smog is bad for our health and damaging to crops and plants. It forms without smoke or fog and is only named the same (smog) because the resulting haze is similar. 

So, what can we do? Well, raising awareness by talking to others about what you learn is key. That's why I'm writing this blog and telling you!  We can also think about how we can reduce chemicals in the atmosphere. We might choose to walk, cycle or get the bus rather than travel by car. We might choose natural household cleaners and detergents over chemical ones. It can be as simple as choosing a roll-on deodorant over a spray (aerosol) one. By talking about what we learn we can encourage others to sign petitions that raise awareness of issues like air quality and  to vote for politicians who show by their voting record that they take issues relating to climate seriously. There are lots of things that can be done, gaining an understanding of the problems and their causes is the first step. 

Let’s look at the weather observations sent in by schools this week. I wonder if anyone has mentioned the fog!

School comments:

Stanford in the Vale Primary School: It’s been a windy week and we have finally got to see two digit numbers with the temperatures finally. We can see spring is just around the corner with buds on the trees and snowdrops around the school grounds. We are checking our bulbs every day at the moment. 

Livingston Village Primary School: We noticed that all the bulbs have started to grow which are the daffodils. Last year’s daffodils have started growing too.

Irvinestown Primary School: We had snow this week!

Logan Primary School: We have some little green shoots in our plantpots

Sacred Heart Primary School – Omagh: Our bulbs are shooting in both the pots and the ground

St Mary's Primary School (Newry): Still no sight of flowers but the shoots are up for the leaves. 

Gavinburn Primary School: After all the rain last week the has been none at all this week and it has felt really cold.

Roseacre Primary Academy: WE can't wait for the flowers.

St Anne's Catholic Primary School – Knowsley: Other days not recorded as ground frozen and path slippery

Fleet Wood Lane Primary School: We are starting to take pictures of the bulbs because we can see the start of the daffodil flowers.

Hello bulb buddies,

What an interesting time to be studying and observing the weather! Most of you will have had frost and cold winds this last week. I've heard that many schools have had to close in January because of the effects of extreme weather conditions, such as ice and floods.  Even on days where schools were open, conditions in the school grounds may have meant you weren’t able to collect weather data.

It’s likely that you’ve heard people talking about weather warnings a lot recently. Weather warnings are released by the MET Office (the UK’s official weather service) and are colour coded (green, yellow, amber and red) to indicate how extreme the weather will be in different areas.

Green: weather is not expected to be extreme.

Yellow: possibility of extreme weather so you should be aware of it.

Amber (orange): strong chance of the weather effecting you in some way, so be prepared.

Red: extreme weather expected, plan ahead and follow the advice of the emergency services and local authorities.

The Met Office also use symbols to indicate what type of weather to expect. For example, the symbols to the right show (in order) a red warning for rain, green for wind, green for snow, amber for ice and green for fog. This means there will be heavy rain and that you should prepare for ice. Why not have a look at the Met Office website and see what the weather forecast is for where you live?

The Met Office warn us about bad weather so that we can prepare for it. This is because extreme weather (such as strong winds and ice) can cause difficulties and make it hard to travel. Roads and train lines can close, flights can be cancelled, and walking conditions can be dangerous.

What was the weather like where you live? If you weren’t able to collect weather records you can enter ‘no record’ on the online form, but please let me know in the comment section what the weather was like! You can also let me know how your plants are doing and whether they have begun to sprout!

Keep up the good work Bulb Buddies,

Professor Plant