Tag Archives: STEM

#TryThisTuesday Halloween Special!

Slime Two Ways

Happy Halloween! Here’s two of our favourite ways to make spooky slime with things you’ll find lying around the house, or in your local supermarket.

Magnetic Slime

Step 1

Ask an adult to help you remove the ink tube from the highlighter using a pair of scissors and squeeze the ink into the bowl. You might want to wear some plastic gloves to avoid getting the ink all over your hands!

Step 2

Add the liquid glucose and mix (we added Halloween confetti at this point for an extra spooky edge!)

Step 3

Gradually add cornflour and mix to get a slimy consistency, then add iron filings and mix, adding more as necessary.

Step 4

Move the magnet on the outside of the cup, and watch as the slime creeps up the side!

Step 5 (optional)

If you have access to a black light, shine this at the cup to make your slime glow in the dark!

      

The science!

The cornflour and liquid glucose mix together to create a non-Newtonian fluid, a fluid that changes in viscosity (how runny it is) with a change in pressure applied to it.

When the iron filings are added and dispersed throughout the slime this makes the mixture magnetic!

The black light emits ultraviolet light which is invisible to the naked eye, but when shone on the highlighter it emits a brilliant glow!

Reversible blood slime

Step 1

Carefully cut open the lining of the nappy and shake out the crystals from inside onto a sheet of paper. You may get some cotton coming out too so just be careful to take this out before step 2!

Step 2

Put the crystals from the nappy into the bowl or container, you’ll only need about a tablespoon full, and add about 250ml water and a splash of red food colouring

Step 3

Stir the mixture and watch closely as the water is absorbed by the crystals and begins to look like a thick slime! Again, we added Halloween confetti to ours to make it even more mysterious!

Step 4

To reverse this process, and turn the slime back into water and food colouring, all you have to do is add salt and mix and watch as the process takes place.

 

The science!

The crystals that are in the lining of nappies are known as a hydrogel. The hydrogel here is a polymer (a long chain of repeated molecules) called sodium polyacrylate and is superabsorbent, meaning it expands when it comes into contact with water and can hold a huge amount of liquid!

When the salt is added, the polymer collapses due to the a change in the ionic concentration of the solution and so the water-holding ability of the hydrogel is broken.

Black History Month: Influential Figures in STEM

October is drawing to a close, which means it’s time for our final installment of profiles for Black History Month. We take a look at astronaut and scientist, Mae Jemison, and renowned zoologist, Ernest Everett Just. We’ve barely scratched the surface of the achievements of black people in the STEM industries, but we hope we have inspired you with some amazing stories. If there’s anyone else you’d like to share with us don’t forget to comment below!

Black History Month: Influential figures in STEM

To honour Black History Month we’ve created a series of posts profiling inspiring and influential black people throughout history in the science, technology, engineering and maths industries. This week we’re looking at the achievements of pioneering botanist, George Washington Carver, and NASA’s extraordinary mathematician and physicist, Katherine Johnson. Visit the blog next week for more.

Sci-Fi vs Sci-Fact

It’s World Space Week, so naturally, we seized the opportunity to stick on our favourite sci-fi blockbusters. However, with our scientific minds always at work, we couldn’t rest easy without sharing with you those space movies that are more fiction than science…

Star Wars

Okay, so we appreciate this galactic fantasy series isn’t ever going to be exactly scientifically accurate, what with all the aliens, droids, space travel and the mystical “Force”. But those space battles that Star Wars is known for, featuring all kinds of explosions and blasts? Well, in reality, they would actually be silent. Sound waves travel via the vibration of atoms and molecules in a medium such as air. Space is a vacuum, devoid of all matter – including gases – meaning the sound vibrations wouldn’t work.

Armageddon

Even if it were feasible to land on an asteroid and drill into the centre of it (just in case you were wondering, it isn’t), the energy required to destroy this huge, Texas-sized, asteroid would amount to a LOT more than one nuclear bomb. The most powerful nuclear bomb ever detonated on earth, Big Ivan, has a total energy output of 418,000 terajoules. Leicester post-graduate students found that in order to split this asteroid in two, Bruce Willis would have had to detonate a bomb with 800 trillion terajoules of energy output.

The Martian

Ahh, a little respite from the scientific disaster that is Armageddon, The Martian is actually hailed as one of the most scientifically accurate sci-fi movies of all time. The main plot line (humans visiting Mars) looks to be scientifically feasible at some point in the future, and growing potatoes with a combination of your own excretion and Martian soil? Possible, apparently. However, whilst we’re willing to give credit where it’s due, this film is not without its inaccuracies.

The main scientific issue with this film is actually the driving force behind the whole plot – the sand storm that leaves Matt Damon’s character, Mark Watney, stranded on Mars. Whilst sand storms definitely do occur on Mars, the atmosphere is so thin compared to Earth’s that a 100mph wind on Mars would feel more like an 11mph wind does on Earth – making it unlikely to cause the destruction that sees Watney separated from his crew.

Interstellar

The astronauts in Interstellar make use of a wormhole next to Saturn, which enables them to travel from our galaxy to an entirely different galaxy in a short amount of time. According to Einstein’s theory of general relativity, wormholes are a possibility.

A wormhole is created by warping the fabric of space-time. If you think of space as a flat piece of paper, the distance is great between one end of the paper and the other. Bend the paper in half and the opposite ends of the paper are now much closer – punch a hole between the two ends of paper and you now have a tunnel which grants you instantaneous access between both ends, instead of travelling the long way from one end of the flat sheet of paper to the other.

However, astrophysicist Kip Thorne points out that in reality, there is a strong indication that wormholes through which humans could travel are forbidden by the laws of physics. Should we ever come across one, a wormhole is likely to be so unstable that the walls of it will collapse so fast that nothing is able to make it through.

Gravity

A central plot point in this film depends on Clooney’s character, Matt Kowalski, whizzing from the Hubble Space Telescope to the International Space Station using his jet pack. However, Hubble orbits at an altitude of 559 kilometres whilst the ISS sits at 423 kilometres; the distance in orbit between the two makes travelling between them completely unfeasible (especially in a jet pack).

World Animal Day

Today is World Animal Day, a day to celebrate and raise the status of animals. Humans are often thought to be the animals with the highest status and intelligence due to our effortless ability to use tools, develop language and dominate the globe. However there are millions of species that have evolved traits and talents that humans could only ever dream of. Here is our list of some of the most amazing animal adaptations.

1. Bioluminescence


Bioluminescence is the ability to emit light. Fire flies and glow worms are well known for their ability to light up but they are not alone, lots of insects and even a species of snail (Quantula striata) hold the protein Luciferin, allowing them to emit light. The protein reacts with oxygen using a specific type of enzyme – luciferase. The chemical reaction gives off the bright glowing colours.

Deep down in the ocean, there is little light from the sun so many marine animals have evolved bioluminence. Others, such as the Sea Goosberry above don’t emit their own light but can refract light to give this dazzling rainbow effect. Even if it’s not technically bioluminescent – we’re still very jealous!

2. Camouflage

In contrast to flashy bioluminescent animals that stand out, some creatures prefer to blend in…

When you think of a camouflaged animal, most people would think of the classic colour–changing chameleon but octopus and squids are the real masters of disguise. They have thousands of cells known as chromotaphores across their skin, these contain pigments and can expand and shrink to change the colour of the skin. These animals can also change the appearance of their skin’s texture and use their soft body and tentacles to morph into a different shape.

The Mimic Octopus takes this a step further and manipulates its body into the shape of other animals to fool its predators into thinking it’s a different marine species – now that would be a fun superpower to have!

3. Mimicry

All the most famous superheroes have a disguise! Like the mimic octopus, some relatively harmless animals have found a clever way to avoid predators by copying the colours, body shape and even behaviour of harmful species. This is known as Batesian Mimicry, and can be seen in animals such as the caterpillar Hemeroplanes triptolemus above, which cleverly disguises itself as a poisonous snake by blowing air into its head!

Mimicry can also happen when two harmful species that have a common predator evolve separately to have similar warning signals such as bright colours or patterns, that show the predators that they are poisonous or taste unpleasant.  This is known as Mullerian Mimicry and can often be seen in butterflies and snakes. So two entirely different (and possibly poisonous!) species of butterflies may look identical.

4. Invisibility

Glass Squid

If camoflauge doesn’t work, how about being invisible? Maybe not completely invisible, but many species have come close by evolving to become transparent. The glasswing butterfly has evolved to have transparent panes in its wings, making it more difficult for predators to spot.

The glass squid and some species of jellyfish have evolved transparent bodies making them extremely difficult for predators to spot them in the depths of the ocean.

5. Regrowing limbs

Image result for axolotl

If all these adaptations for hiding fail and you’re caught by a predator – what next? Well some species such as the Mexican salamander, the axolotl, have evolved the ability to regrow parts of the body so it’s not a big deal if something does take a bite out of them.

When an axolotl loses a limb, the cells at the cut off point lose their identity; they are no long skins cells or muscle cells and they become generic cells that are able to develop into whatever the axolotl needs them to be to regrow whatever was lost. Whilst humans have come a long way in developing amazing prosthetic and even bionic limbs, we’re unlikely to evolve the ability to completely regrow body parts anytime soon.

If you want to see some amazing axolotls yourself, take a trip to Newcastle University’s Natural History Museum, the Great North Museum: Hancock.

6. Outside Digestion

Speaking of regrowing limbs – starfish can also happily regrow spines but that’s not their only talent – they can also digest their food in a very interesting way. Instead of taking food in through the mouth, instead they take their stomach out of their body and put it on the food. Their stomach then digests the food into a mushy soup which the starfish can then draw into it’s body along with it’s stomach.

Perhaps this wouldn’t be top priority for a superpower but it is impressive! You can see the starfish in action in our aquarium at the Dove Marine Lab in Cullercoats.

7. Flight

Image result for bar tailed godwit

Moving from the seas to the skies, I’m sure many of us would love to have the ability to fly. Of course many creatures have mastered this, mainly birds and insects but some reptiles, fish and mammals, such as the flying squirrel, have evolved flaps of skin that allow them to glide through the air.

One of the most impressive flyers of the animal world is the bar-tailed godwit. This little bird weighs around 500g but is capable of flying immense distances. The longest recorded migration of this species was from Alaska to New Zealand – a distance of 11,680km! The journey took nine days and the bar-tailed godwit didn’t stop once. Very impressive considering most of us couldn’t even stay awake for nine days!

8. Echolocation

Onto another famous flyer – the bat. Flight isn’t this mammal’s only superpower as it can also navigate in the dark without sight. It does this by using echolocation. Bats send out a high frequency sound and listen for the echos coming back. By comparing the outgoing sound with the returning sound, bats tell how far away obstacles are, how big they are and even if they are moving. They are able to build up a picture of the world around them using sound, just as we are able to using sight.

This impressive power may not be so out of reach for humans. Several blind people have taught themselves how to navigate using echolocation. They produce sounds either by tapping a cane against the floor, creating clicks with their tongue or snapping their fingers and then listen for the echos, just as echolocating animals do.

9. UV Vision

Image result for uv light reindeer

Whilst some animals, like bats, have relatively poor vision, other see much more than we could imagine. The light that we can see, known as the visible spectrum, covers the wavelengths 380nm – 760nm. Ultraviolet light sits just outside this so our eyes are unable to detect it. Some animals including butterflies, some birds and even reindeer have evolved the ability to see UV.

Reindeer are thought to have evolved this ability as it helps them identify lichens for food, and urine indicating predators in the snow. To us, these would blend in but in ultraviolet light there is much more of a contrast.

10. Mind Control

Our final adaptation may perhaps be the most sought after superpower – mind control. This isn’t just the stuff of science fiction movies and comic books, some animals have actually achieved it. The green-banded broodsac is a parasitic flatworm that infects snails in order to reach birds, their ideal host species. The parasite infects the snails and causes their tentacles to bulge, making them look like a caterpillar. It influences the snail and makes them move from the shade and up to the tops of leaves and branches where they are easily visible to birds. As the tentacles now look like a delicious meal for the birds, they’re prime targets. Once eaten, the parasite is able to continue it’s life inside the bird.

Which of these animal superpowers would you like to have?

#TryThisTuesday: Virtual Treasure Hunt

To celebrate International Talk Like a Pirate Day we have put together a virtual treasure hunt that you can do from a phone or computer.

For this treasure hunt you will need to solve clues to find co-ordinates to the next stop . The first three people to make it to the end of the hunt will win the treasure of a Street Science Busking Kit which is filled with equipment to make amazing science demonstrations at home!

Using Co-ordinates

Geographic co-ordinates allow every place on Earth to be identified with a set of numbers. The system that we’re using for this treasure hunt gives every point a latitude number and a longitude number.

If you were to draw a line from your point on the globe into the centre of the Earth and another from the centre of the Earth to the Equator, the angle between these two lines gives you the Latitude.

Longitude is measured slightly differently.  There is an invisible line running from the North Pole to the South Pole through the Royal Observatory in Greenwich, London, known as the Prime Meridian.  All points along this line have the longitude 0. The longitude of other points are calculated as the angle east or west from the Prime Meridian.

So Newcastle Upon Tyne, where we’re starting our treasure hunt from, has the co-ordinates 54.97, -1.61 because it is 54.97 degrees from the Equator and 1.61 degrees to the west of the Prime Meridian. Going west of the Prime Meridian or south of the Equator gives the co-ordinate a negative value.

 

The Treasure Hunt

Try to solve the clues to find the co-ordinates for the next place. Once you’ve got co-ordinates type them into Google maps (just like this: 54.97, -1.61 with latitude first) and make a note of where you’ve got to.

This will test your research skills as well as your maths skills, feel free to use Wikipedia and a calculator.

Destination One

The latitude for the first place is 57.14 divided by the number of universities in Newcastle Upon Tyne.

The longitude is  equal to 10 – 90.65.

Where are you?

 

Destination Two

To find the latitude of our second destination, take the last two digits of the year the first man walked on the moon, half this number then add 3.32

The longitude can be found by taking the year Newcastle University became independent from Durham University away from the year that the oldest part of the university (the School of Medicine and Surgery) was established and adding 6.52.

What amazing feat of engineering are you near?

 

Destination Three

For the latitude of our next place, take away 3.1 from the distance that Destination Two stretches in miles.

The longitude can calculated by the number of different countries that students at Newcastle University have come from divided by -2.

Which wondrous forest have we arrived at?

 

Destination Four

The latitude of this place can be uncovered by multiplying the number of countries that share Destination Three by 5 then adding 1.234

The longitude is equal to the number of reptile species that have been discovered in our previous destination divided by 63 then add 0.053

What amazing discoveries were made here?

 

Destination Five

The above place is often known by an abbreviation of four letters. If you convert these letters to numbers (eg. a=1, b=2, c=3 etc.) and square the second number, then add 0.197 you will have the latitude of our next  destination.

To find the longitude, convert the first letter of the abbreviation to a number and take this away from 58.274.

Which incredible man made structure are you looking at now?

 

Destination Six

For the latitude of our final place – where the treasure is buried – you will need to divide the total height of the structure we just saw (in metres) by -46.1.

To find the longitude, simply take away 16 from the number of floors in this structure.

Where is our treasure buried?

If you think you’ve cracked it, either send us an email to stem@ncl.ac.uk or comment below with the six places the co-ordinates led you to!

 

#TryThisTuesday: Rice Bottle

Our #TryThisTuesday this week, is a challenge for you. The task is to fill a dry bottle with rice and lift it up using only a pencil.

Have a go or challenge your friends, once you think you’ve cracked it (or given up) scroll down to see how we did it!

The Solution

Take the lid off the bottle and push the pencil half way into the rice. Take the pencil out again and push it back in, repeat this about 10 times. Eventually, when you pull the pencil to take it out, the bottle will lift up with it!

This occurs due to the force of friction acting on the pencil and holding it in place. When you first pour the rice into the bottle, it will arrange itself with lots of gaps but every time you insert the pencil you push the rice down making it more compact or dense. Some grains may even break or change shape under impact with your pencil. The more you do this, the greater the surface area of rice that comes into contact with the pencil. This gives a greater force of friction. Friction is a force of resistance between two objects when they  move past each other. The force is so strong at this point that it doesn’t allow the pencil to slip past the rice and so the rice (and the bottle) moves with the pencil as you lift it.

In the Real World…

This works in a similar way to quicksand. If you were to step onto quicksand, you would compact the particles, making them move closer together and lock around your foot, pulling you in. The friction makes it difficult for you to pull your foot out. Don’t worry too much though – quicksand is much denser than a human being so you wouldn’t be able to completely sink in it. As we learnt from our ketchup packet submarine and the oil and water experiment – less dense substances float above denser substances so you would stay above the surface of quicksand!

#TryThisTuesday: Bending Water

This week’s experiment is quick and simple but sure to amaze!

You will need:

  • A balloon
  • An indoor tap
  • Clean dry hair

Method:

  1. Turn the tap on so there is a very thin but constant stream of water flowing
  2. Rub the balloon on your hair until you form static (about 10 seconds, until your hair begins to stand on end)
  3. Slowly bring the balloon close to the flowing water while being careful not to actually touch the water
  4. Watch the water bend towards the balloon!

 

The Science

When you rub the balloon on your hair, tiny electrons are collected on the balloon. These electrons have a negative charge. This causes the balloon itself to have an overall negative charge, therefore it is attracted to things with a positive charge (opposites attract!). The flow of water has a positive charge, therefore the attraction is strong enough to pull the water towards the balloon.

This is known as static electricity!