# #TryThisTuesday: Walking Water

#### Our Try This Tuesday series of experiments to try at home is back with a colourful water-based experiment from Street Scientist, Ailie.

You will need:

• Red, yellow and blue food colouring
• Kitchen roll
• 6 Clear cups, roughly the same size
1. Add water to three of the cups so they are 3/4 full. Then add 5 drops of red food colouring to one cup of water, blue into the second and yellow into the third.
2. Place the cups in a circle with the empty cups in-between the ones with water in (You may want to put some paper underneath the cups if you are worried about spills).

3. Take 6 sheets of kitchen roll and fold them twice to make a thick strip as below. You may want to cut them to be a bit shorter if you are using small cups, I cut off the bottom 1/5th.

4. Place one end of each strip of kitchen roll into one of the cups with water in and the other end into an empty cup next to it. Can you predict what colours might form in the empty cups?

5. Wait an hour then check back in to see if your experiment is working! Mine looked like this:

Eventually the empty cups will be as full as the cups feeding into them!

### Colour Theory

Did you notice something the 3 colours you started with had in common? They are the primary colours. Therefore, mixing them creates the 3 secondary colours – purple, green and orange.

This gives us a simplified version of a colour wheel. The colours opposite each other on the wheel, and in our cup circle, are ‘complimentary’ meaning they contrast one another i.e. purple and yellow.

If we were to add more empty glasses in between the colours we have here we would make tertiary colours!

### The Science

The water moves up the paper towel through a process called capillary action which is the ability of water to flow through narrow spaces, even against gravity! Capillary action works as molecules in liquid like to stick together (cohesion) and also like to stick to walls of a tube (adhesion). Together these forces act to propel the liquid through the tube or narrow space. The narrower the space, the quicker the water moves and the higher up it can go.

Plants rely on capillary action to move water all the way up from their roots to the leaves at the very top, where it is needed for photosynthesis (the production of glucose for energy). Just as humans have blood vessels to carry important substances around our body in the blood, plants have a tissue called xylem which is made up of millions of tiny tubes. Water moves up through the tiny cubes by capillary action, without wasting any of the plant’s energy.

One way to easily see capillary action working in the xylem is to cut the very bottom off the stem of celery or cabbage and put it into some water with food colouring. Given enough time, you will see the coloured water move to the top of the plant and stain the leaves. When a plant has been picked it is no longer undergoing photosynthesis and producing energy, therefore we have shown that the water is moving up to the top of the plant by a passive process.

Kitchen roll is designed to be very absorbent meaning it is able to hold lots of liquid – great for kitchen spills. To be able to do this, there are lots of little spaces in-between the fibres in kitchen roll which fill with water. Together they form the narrow spaces which the water uses to move up the tissue and into the adjacent empty cup. There, the colour mixes with the water from the cup on the other side to form our secondary colours.

# STEM Students answer Children’s Questions #4

### What is blood made of?

-asked by Lacey, 8, from Simonside Primary School

There are many things which make up blood! The easiest way to think about it is that it contains liquids and solids. The liquid part of blood is called plasma which is mainly water with some salts dissolved in it and also some proteins. The plasma allows blood to flow, carrying the solids around the body to where they are needed. The salts are important in controlling how much water is in the body, this is why it is dangerous to eat lots of salt!

The plasma makes up around half of blood, the rest is made up of red blood cells, white blood cells and platelets. Red blood cells have a dip in the middle which gives them lots of space to carry oxygen from the lungs to the body. Oxygen bound to red blood cells is what makes blood red.

The white blood cells come in lots of different types and are part of the immune system which protects the body from germs like bacteria and viruses. They recognise germs which don’t belong in the body and kill them in lots of different ways before they can make us sick.

Platelets are important in allowing us to form scabs when we cut ourselves. The platelets all stick together over a cut and stop us losing too much blood.
-Ailie, Medical Student & Evolution and Human Behaviour Masters Student

### Why do people get allergic reactions to things?

-asked by Abbie, 11, Burnside Primary School

Allergic reactions happen in some people when the immune system overreacts to something harmless, called an allergen, because it thinks it is dangerous to the body. Our immune system is very important to keep our bodies safe from germs such as bacteria and viruses that can cause disease. While the red cells in our blood carry oxygen all around the body, the white blood cells make up the immune system.

The white blood cells are very clever at recognising germs in the body and realising that they don’t belong and can be harmful. When they find a germ, they activate other white blood cells to attack the germ in lots of different ways. Some white blood cells can swallow a germ whole and then dissolve it – this is called phagocytosis. Other white blood cells release antibodies which stop the germs being harmful and cause them to all stick together, others release chemicals such as histamine which causes swelling and brings in more white blood cells to help.

However, in some people the white blood cells get confused and think something safe, like peanuts or shellfish, are harmful to the body. Scientists haven’t figured out why this happens to some people but not others although sometimes it runs in families and is linked to other conditions like asthma and hay-fever. When people with allergies eat or touch something they are allergic to the immune system becomes activated causing redness, swelling and itching. In a serious case the throat may swell up making it hard to breathe, this is why some people with allergies carry an EpiPen which contains adrenaline to stop the swelling.
-Ailie, Medical Student & Evolution and Human Behaviour Masters Student

### How many medicines are in the world?

-Asked by Ruby, 10, from Simonside Primary School

It is impossible to know exactly how many different medicines there are, it will be thousands and thousands! The types of medicines used in different parts of the world are very varied and medicines are always changing.

Doctors used to think that all sickness was due to ‘bad blood’ so they put leaches on sick people to suck it out! Luckily, they don’t do that anymore. For most diseases there are many treatments available. For example, there are lots of different inhalers for asthma which are different colours depending on which medicine is inside, and there are tablets you can take too. Which medicine works best depends on the person, sometimes doctors have to try a few before they find the right one. Medicines come in lots of different forms, sometimes you may take an antibiotic as a pill, drink it as a liquid, or have it as an injection.

In summary, there are too many medicines to count! Some things we use every day such as garlic and ginger can be used as medicine if you know what you are doing! Luckily for everyone Scientists and researchers are creating more medicine and treatments every day!
-Ailie, Medical Student & Evolution and Human Behaviour Masters Student

### I would like to work in Tropical Medicine. How long would I need to study for?

-asked by Liam, 11, Burnside Primary School

Lots of people work in tropical medicine including biomedical researchers, epidemiologists, doctors and microbiologists to name a few. So the length of time you have to study for will really depend on what aspect of tropical medicine you want to end up in, most researchers for example will have done 4 or 5 years of university and doctors need to have done 5 years of university and 9 years of specialist training. People who work in tropical medicine are always learning new things even after they’ve officially stopped studying.
-JC, Medical Student

# STEM Students answer Children’s Questions #3

### What made you want to become a scientist?

-asked by Dylan, 10, from Simonside Primary School

Interesting question. I wanted to become a scientist because I find that science is a great way to find out more about the world and how it works. It gives me a whole different way of looking at and understanding the world.

For example, look at your hand and wiggle your fingers, that is all happening due to nerve impulses, which are a form of electricity that travel from the brain along nerves to your fingers instructing them to move.

Or even the reason we see colour such as green is because a green object will absorb all light but green light, and this reflects back making the object look green!

And that’s just the tiniest part of it. There is so much to discover and it’s all so intricate and fits together in such a clever way.

So, a bit of a lengthy answer but in short there is far too much interesting stuff out there for me not to become a scientist and try and find out as much as I can. The best thing is, I will never be able to find out everything, there will always be something for someone else to discover, someone like you, if you wanted!
– James, Biology & Psychology Student

### Does your experiments work all the time?

-asked by Farah, 8, from West Jesmond Primary School

Unfortunately they don’t always work out, but that’s what makes science so exciting since we can still learn things from the times things didn’t work out like we planned. Loads of scientific discoveries and new inventions have been made by accident including X-rays, corn flakes and Velcro.
– JC, Medical Student

### Why do we need to do science?

-asked by Harith, 7.5, from West Jesmond Primary School

That’s a great question. Science is really important because it helps us answer so many questions like ‘why is the sky blue’ but it also can be used to design and make cars, computers and other great things that people use every day.

It can also help us save and improve lives by creating medicines and new treatments for diseases; figuring out the best way to grow enough food for millions of people; and generating electricity to power homes.

Science is even used in places you might not expect like in producing the colour dyes for your clothes and in your favourite sweets!
-JC, Medical Student & Clare, STEM Outreach Officer

-asked by Jonathon, 11, from Burnside Primary School

I love how science lets me understand all the amazing mysteries in the world, from gravity which stops us from flying into space to electricity which powers my home!

I’m particularly interested in the science of biology and the human body, I find all the different ways the body adapts to change to keep us healthy very clever. Everything in the body is in balance, the lungs breath in more oxygen to supply our muscles when we exercise, and the kidneys hold in salt and water when we are dehydrated. Wanting to learn more, I decided train to be a doctor to learn how to fix the body when things go wrong.

I am amazed by the inventions and discoveries by scientists that help us treat diseases more efficiently. X-rays and CT scanners allow us to see inside the body from the outside while antibiotics and vaccinations treat and prevent infections that would otherwise be fatal.

My overall favourite thing about science is that as it is so broad, there is something to interest everyone! A scientist can be anyone from a zoologist to a nuclear physics to students doing experiments in school! Science is always changing as scientists and researchers making new discoveries that challenge the way we see the world, and engineers and computer scientists come up with inventions that change our day to day life.
-Ailie, Medical Student & Evolution and Human Behaviour Masters Student

# International Asteroid Day!

### What is an asteroid?

You may be wondering what the difference is between an asteroid, meteor, meteorite and every other name given to a shooting star or flying clump of rock in space. Well we have broken it down into an answer that is simple….. Sort of. It all starts with an asteroid.

An asteroid is a large rocky (planet looking) body, in orbit of the sun, that is too small to be classified as a planet. In space there are millions of asteroids and lots of them are a potential threat to Earth. Asteroids range in size from hundreds of miles to several feet in diameter.

A meteoroid is a particle of an meteoroid that has broken off and is now orbiting the sun. If a meteoroid enters the Earth’s atmosphere it is then known as a meteor. A meteor shower is a group of meteoroids all travelling in parallel trajectories from one point in space. Most meteors burn up when they are travelling through our atmosphere and therefore never hit the earth’s surface. The meteors that do hit earth are called meteorites.

### Asteroid defence?

Over the past 4.5 billion years since the Earth was formed, about 4.5 billion meteors (the sizes of cars) have made their way through its atmosphere. Yes, that’s around one automobile sized meteor every year. Although, these are meteors and not meteorites, therefore they create a substantial fireball but burn out before hitting the ground.

Scientists these days are able to tell if an asteroid or meteor is en route to earth 30-40 years before it does. This is enough time for us to destroy it before it destroys us. We can do this by exploding the asteroid or meteor, although sometimes we can divert them away from earth instead.

### When is the next meteor shower?

Unfortunately you will have to wait a couple months for our next meteor shower, it is called Perseid and will be peaking in our skies on the 12- 13th of August. In order to get the most out of your meteor shower view, we recommend getting out into the middle of nowhere where there is little to no light pollution; bringing a friend or your family and a warm blanket (also a telescope if you’ve got one). Once you’re comfortable, sit tight and wait for the spectacular starry show!

# Earth Day | Plastic Pollution

On the 22nd April 1970, millions of US citizens united to celebrate the first ever “Earth Day“. This brought together people from all walks of life and political backgrounds who each had one thing in common – they cared about the environment. The fight to keep environmental protection on the global agenda and to push for change becomes ever more urgent as we face imminent threats from pollution and climate change. Today, billions of people from around the world are using Earth Day to try and galvanize a global movement towards ending environmental destruction and tackling crises such as climate change and plastic pollution.

Plastic pollution, the focus of 2018’s Earth Day, is an issue that has exploded into prominence over the past couple of years. Relative to human history, plastic has been around for an incredibly short amount of time – around 60 years – and yet, in that time, we have produced over 8.3 billion tonnes of plastic, nearly all of which still exists on earth in one form or another – predominantly as waste, either in landfill or the natural environment.

Only a small percentage of plastic, under 9%, ever gets recycled, meaning that tonnes of virgin plastic continues to be produced all of the time. An estimated 300 million tonnes of plastic now litters the oceans, posing a threat to marine ecosystems and wildlife. At the rate plastic is making it’s way into the sea, it will outweigh fish by 2050.

A study, led by Newcastle University’s Dr Alan Jamieson in 2017 uncovered evidence that not only have plastics now reached the deepest chasms of our oceans but they are being ingested by the animals that live there. Using deep sea landers to bring samples to the surface, the research team examined 90 individual animals and found ingestion of plastic ranged from 50% in the New Hebrides Trench to 100% at the bottom of the Mariana Trench.

This type of work requires a great deal of contamination control, but that the results were undeniable, with instances where synthetic fibres could actually be seen in the stomach contents of the specimen as they were being removed. Dr Jamieson explains that this finding likely means that there is not a single marine ecosystem left that is not impacted by anthropogenic debris.

“The fact that we found such extraordinary levels of these pollutants in one of the most remote and inaccessible habitats on earth really brings home the long term, devastating impact that mankind is having on the planet,” says Dr Jamieson.

“It’s not a great legacy that we’re leaving behind.”

Litter is not the only plastic problem; plastic is a petroleum product and it is estimated that plastic products account for around 8% of global oil production.

“The drilling of oil and processing into plastic releases harmful gas emissions into the environment including carbon monoxide, hydrogen sulfide, ozone, benzene, and methane (a greenhouse gas that causes a greater warming effect than carbon dioxide) according to the Plastic Pollution Coalition. The EPA estimated that five ounces of carbon dioxide are emitted for every ounce of Polyethylene Terephthalate produced.” (Earth Day Network)

Plastic is undoubtedly having a hugely negative impact on our planet and it’s inhabitants, but it is a problem that can be solved. As research, such as that from Newcastle University, brings the extent of the problem to the forefront, more and more people begin to take notice. As individuals begin to realise that everyday actions have wider consequences for the environment, we can start to implement change.

We can each take responsibility for our choices and choose to make simple changes in our lives that will cut the demand for single use plastic, such as swapping out plastic drinks bottles for reusable ones and remembering to take reusable shopping bags with us to the supermarket. Changes are also starting to come around on a larger scale, as governments become more informed on the plastic problem, they can create more widespread change; for example, the UK government have proposed a ban on plastic straws and cotton buds and are discussing plastic bottle return schemes.

The scale of the issue can make it seem as though any small changes we make will not be enough, but just as scientific research continues to uncover the dangers of plastic pollution, it can also work towards solutions.

Find out more about the impact of Newcastle University’s research here.

# National Tea Day | The Science of a Perfect Cuppa

#### This National Tea Day, Hattie explores the science behind a top notch cuppa…

76% of people in Britain drink at least one cup of tea a day, but when it comes to making the perfect brew opinions are divided, arguments ensue, disagreements are rife. How long do you brew? Do you add milk? If so, when? And let’s not even begin to talk about the different shapes of tea bag. Everyone has their perfect method, but we decided the best way to settle the debate was, of course, to use science!

The Water
Firstly, aim to use soft water, that is, water with low concentrations of ions of calcium and magnesium, to avoid that unwanted scum on the top of your tea. Also, try and use water that hasn’t been previously boiled. This is because pre-boiled water has lost some of the oxygen that tea needs to release all those lovely flavours. For black tea in particular, the highest possible temperature is desirable to ensure a lot of oxygen is involved in the brewing process.

The mug
In terms of mugs, historically tea should be drunk from a fine porcelain cup, as it can withstand the high temperatures of the boiling water, when in bone china cups this may cause cracks. According to the Institute of Physics however, the temperature problem can be avoided by (controversially) adding the milk to your mug first to cool the tea and prevent the mug cracking. Also, if you have more of a sweet tooth, opt for a red or pink mug as this can bring out the tea’s natural sweetness.

The milk
According to the Royal Society of Chemistry, when milk is poured into hot tea, the overall taste of the drink can be significantly affected. This is because proteins in the milk begin to degrade when heated above 75°, changing their taste. On the other hand, however, University College London claim that adding milk last allows the compounds within a teabag that make your cuppa delicious to be released more effectively as the temperature isn’t reduced by the milk.

The time
Researchers claim that 3 to 4 minutes brew time is optimum to ensure maximum flavour is released and the levels of tannins and antioxidants are just right. Tannins have been proven to hold some health benefits including reducing blood pressure, however they can leave a nasty aftertaste in your tea.

There you go, the science behind a good old cup of tea! How will you be drinking yours this National Tea Day?

# Smell and Memories

#### In this week’s blog post, psychology graduate, Maria, explains the science behind smells that help us recall vivid memories.

We probably don’t analyse why we see the world around us, feel, touch or smell a wide range of scents…but all of these senses require a complex system of brain areas. Our sense of smell in particular has an amazing ability to ‘mentally transport’ us back to previous emotions or memories –  but why does this happen? How does this happen?

Psychological and neurobiological research has shown that when we sense an incoming smell, it is processed through many brain areas that are directly connected to emotion and memory brain centres. The olfactory bulb, which starts in the nose and runs alongside the bottom of the brain, has strong connections with our amygdala (an emotion centre of the brain) and hippocampus (helps in memory). Interestingly, our visual, sound and touch information don’t pass through these areas, explaining why olfaction (smell) can so successfully trigger emotions and memories. Although we tend to rely heavily on vision, our sense of smell can be a very powerful tool in day-to-day life!

This association between smells and remembering can also have valuable implications for revision and learning information.  Psychology researchers have found that smells can be associated with facts or information, to allow for better recall in the future. In principle, we may be able to train our brain to remember information using scent, maybe by using different scents for different concepts. Give it a go and put those candles to good use!

# #WorldWildlifeDay – Big Cats: predators under threat

World Wildlife day aims to celebrate and raise awareness of the world’s wild plants and animals. The theme for this year is Big Cats: predators under threat and aims to highlight the ecological importance of charismatic creatures such as cheetahs, jaguars, leopards and lions and promote their conservation and survival in the wild.

Humans have always been fascinated by these animals as is made clear by their influence on high fashion, fast cars and sports teams the world over. However they are becoming increasingly rare due to human-led activity such as poaching and deforestation. Conflict often occurs between humans and big cats due to lack of prey such as deer for the animals. This can cause the big cats, such as tigers, to predate on livestock, causing humans to poach in retaliation to protect their livelihoods.

Collectively, big cats are under threat and many species are classified on the International Union for Conservation of Nature (IUCN) Red List as being endangered or critically endangered, meaning the range they inhabit in the wild is getting smaller and their population sizes are rapidly declining.

Many efforts exist for conserving these animals, including breeding programmes in captivity, maintaining protected areas to prevent poaching, and projects such as World Wildlife Day increasing awareness of the threats to populations.

# The Science of Santa

We all know Father Christmas is one of the most wonderful and magical parts of Christmas, so we thought we’d use our scientific knowledge to work out how the fastest man in the universe delivers all those presents in one night!

There are approximately 2 billion children in the world. Of those, about 700,000,000 celebrate Christmas (and make the nice list!). With an average of three children per house, that’s a whopping 233,000,000 stops that Saint Nick has to make! Now bear with us…

If those stops are distributed evenly around the world, with a total surface area of 317,000,000 miles, each stop is 0.91 miles apart, making a total of 212,030,000 miles that Santa has to travel.

Because of the time differences across the globe, Santa has approximately 32 hours to complete his trip, maximising the night time (and sleeping children) available. Using speed = distance ÷ time, we can then work out that he has to travel at 6,650,807.72 mph! That’s about 1,800 miles per second.

So, remember to leave out a mince pie or two to help him along on this, his busiest of nights!

# #TryThisTuesday Crystal Christmas Decorations!

## Crystal Christmas Decorations

It’s the most wonderful time of the year… and for this #TryThisTuesday Christmas Special, we’re making beautiful decorations for your Christmas tree using science!

### Step 1

Mould your pipe cleaners into the desired shape, we chose to make a Christmas tree out of green pipe-cleaners, and a snowflake out of white pipe-cleaners

### Step 2

Carefully fill a large container with boiling water then add the salt bit by bit, stirring continuously, until the water is saturated.

This means that the salt stops dissolving and instead sits at the bottom of the water, as the water can no longer hold any more salt crystals.

### Step 3

Tie one long piece of string around your decorations in a row

### Step 4

Dip the decorations in the water, and suspend over the container (as shown in the picture)

### Step 5

This next part will take some patience!

Over the next 24 to 48 hours, watch as the crystals develop around the fibres of the pipe-cleaners, and see your beautifully festive decorations develop!

### Step 6

Tie a piece of string around the top of your decoration and hang on your tree!

### The Science

Salt crystals are formed due to ionic bonding, meaning they form a specific pattern which is always a square shape. When salt is dissolved into water, the water molecules separate the salt molecules. This means that even when it looks like the salt has disappeared in the water, it is actually there all along.  This happens especially well in hot water, as the heat means the water can hold many more salt molecules than cold water. As the water cools and evaporates, the salt crystals bond again as the water can no longer hold all the salt. The crystals stick to the pipe-cleaners because as the water evaporates, it takes some of the salt with it which clings to our suspended decorations, leaving beautiful crystal ornaments!