All posts by Ellie

#TryThisTuesday: Rock Candy

This weeks Try This Tuesday takes a while, but you end up with a tasty treat!

You will need:

  • A wooden skewer or chopstick
  • Peg
  • 1 cup of water
  • 2-3 cups of sugar
  • A narrow glass or jar

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Clip the wooden skewer into the peg so that it hangs down inside the glass and is a couple of centimetres off the bottom.

Put the water into a pan and bring it to the boil. Pour about a quarter of a cup of the sugar into the boiling water and stir until it dissolves.

Keep adding more and more sugar, each time stirring it until it dissolves, until no more will dissolve. This might take quite a while!

When no more sugar will dissolve remove it from the heat and leave it to cool for about 20 minutes.

Pour the sugar solution into the glass or jar almost to the top. Then put your skewer back into the glass so it hangs down and doesn’t touch the sides.1st

Leave your glass in somewhere it won’t be disturbed. The sugar crystals will grow over 3-7 days. Once these have grown you can eat them!finished-product

The Science

By mixing the sugar and water together when they were really hot, you have created a super saturated solution. This means that the water contains much more sugar than in could in normal circumstances. As the water cools back down the sugar leaves the solution (mixture) and becomes sugar crystals again, forming on the skewer.

Supersaturated solutions are used in real life. In a sealed fizzy drink the drink is saturated (full) with carbon dioxide, as the carbon dioxide is put in using pressure. When you open the drink, the pressure of the carbon dioxide is decreased, which causes your drink to be supersaturated as there is much more carbon dioxide dissolved than there would be at normal pressure. The excess carbon dioxide is given off as bubbles.

#TryThisTuesday: Exploding Lunch Bag

Today we are going to make an explosive lunch!

You will need

  • One small (sandwich size) zip-lock plastic bag
  • Bicarbonate of soda
  • Warm water
  • Vinegar
  • A tissue

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Do this experiment outside, or at least in the kitchen sink. Put about a quarter of a cup of warm water in the bag with half a cup of vinegar.

Put three teaspoons of the bicarbonate of soda into the middle of the tissue and fold it up into a little parcel.

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Partially zip the bag closed but leave a little space to add the bicarbonate of soda parcel in. Put the tissue parcel in the bag and quickly zip the bag completely closed.

Put the bag on the ground and step back. The bag will start to expand and hopefully pop!

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The Science

The bicarbonate of soda and the vinegar eventually mix together, the tissue just gives you enough time to get the bag shut. A reaction takes place between the alkaline bicarbonate of soda and the acidic vinegar, this is know as an acid-base reaction. The reaction produces carbon dioxide, which begins to fill the bag. After a while the bag can no longer hold any more gas so it pops!

The reactions between acids and alkalis are used lots in real life too. Farmers can treat acidic soil with alkaline lime fertilisers to neutralise the soil and allow plants to grow. It’s also a good way to treat a wasp sting; wasp stings are alkaline so you can treat them by putting vinegar on the sting.

#TryThisTuesday: Chicken Sounds from a Cup!

This week we are going to make chicken sounds from a cup!

You will need:img_4715

  • plastic cup
  • string
  • paperclip
  • paper towel
  • scissors
  • water
  • pin

 

 

 

First put a hole in the top of your cup. We found it easiest to push a pin through and then make the hole larger with scissors.

Cut a piece of string that is about 20cm long and put it through the hole in the cup.

Tie the top end of string to the side of the paper clip.img_4716

Wet the paper towel. Hold the cup in one hand and wrap the paper towel around the string near the paper cup. Squeeze the string and pull down in sharp jerks to make the chicken noise!

The Science

Sound travels in waves, which cause particles to vibrate and causes the sound. The vibrations from the string would normally be almost silent without the cup.

When you add the cup it amplifies the sound and makes it much louder. This is because the cup is a solid object, and there are lots of closely squashed together particles in a solid object for the sound waves to hit and vibrate. The more vibrations the LOUDER the sound.

 

International Girls in ICT Day 2017

There is a huge shortfall of ICT professionals worldwide, with many companies looking to increase the number of women working for them. However, many girls don’t even consider a career in ICT. We decided to celebrate some influential women in ICT from the times computers were invented to now.

Ada Lovelace

Ada Lovelace

Ada was an English Mathematician who worked on the ‘Analytical Engine’, one of the first designs for modern computers.  She recognised that computers could do a lot more than was previously thought and designed the first algorithm that could be carried out by computers. She is often called the first computer programmer for designing this.

Joan Elisabeth Lowther Murray

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Joan was an English cryptanalyst (analysing information systems to breach cryptographic security systems) who is best known for her work as a code breaker at Bletchley Park during World War II. She worked on the Enigma project, which cracked the German system of encoding their messages and led to WWII being much shorter and saving thousands of lives. The Enigma project was a very early form of ICT.

Grace Hopper

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Grace was an American Computer Scientist and a United States Navy Rear Admiral. She was the first person to develop a compiler, despite being told by many people that it would never work. A compiler is a programme that changes what you write on a computer into a language that can be understood by the computer. This allows computers to work with words rather than just numbers as was previously done. There is now a yearly Grace Hopper Celebration of Women in Computing, giving women in computer science a chance to share their research.

Anita Borg

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Working as a computer scientist  she developed ways to analyse high speed memory systems in computers. She founded Systers, a network for women in technology, and the Grace Hopper Celebration of Women in Computing. In 1997, she founded the Institute for Women and Technology (now the Anita Borg Institute), to increase the number of women in technology and their impact on the world.

Marissa Mayer

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She joined Google as employee number 20 and as their first female engineer after studying computer science at university. She oversaw the layout of Google’s home page and became Vice President of search products and user experience. In 2012 she became president and CEO of Yahoo! and led them to buy Tumblr in 2013.

Earth Day 2017

It’s the planet that we live on and home to 7 billion people as well as billions of plants and animals. But with climate change and other issues such as pollution, we need to do more to look after our home. Earth Day gives the opportunity to come together and work toward a greener future, showing support for the environment. earth-day

Why is it important?

Humans are using resources at an alarmingly fast rate, currently using more resources than the Earth can produce. Today humans use 1.5 planets’ worth of resources every year!

Climate change is a huge problem for the future of our planet. It will lead to things like increased sea level and flooding, drought, and a rise in temperature. This will make it more difficult for plants and animals to survive and hence humans. Scientists agree that we can reduce the impacts of climate change, but we need to act as fast as we can.

There are lots of other environmental issues such as deforestation, pollution and ocean acidification that are affecting the environment.  These problems can lead to a loss in the number of animal and plant species causing the Earth to have reduced biodiversity (the number of species). Lots of plants and animals are interlinked in food chains, so losing one can have a knock on effect on other species. Biodiversity is vital to our survival, for supporting the ecosystem, finding things like new medicines and for providing humans with lots of raw materials.

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How can we help?

There are lots of things we can do to reduce our footprint on the Earth. These are just some things you could try and do:

  1. Shop for locally sourced produce
  2. Eat food that is in season
  3. Eat less meat
  4. Bring your own shopping bags
  5. Use a reusable water bottle rather than bottled water
  6. Don’t drive if there is an alternative
  7. Take holidays closer to home
  8. Recycle
  9. Use energy saving lights
  10. Unplug your electronics when not in use
  11. Plant a tree
  12. Use a reusable coffee cup

 

Ten Amazing Facts about the human body!

You take it everywhere you go, but I bet that there are a few facts about your body that you didn’t know!

1. There is enough DNA in the human body to stretch from the Sun to Pluto and back – 17 times! 

There are about 37 trillion cells in the human body, all of them containing about 5cm of of DNA (when uncoiled). DNA is made up of lots of different nucleotide pairs that can decide some of our features such as eye and hair colour.

2. The average human body contains ten times more bacterial cells than human cells.

However bacteria are much smaller so don’t take up that much space. Lots of these bacterial cells are important, such as intestinal bacteria that help keep our immune systems healthy.unravelled-dna

3. Except for identical twins, each person on Earth has a unique smell.

Just how we each have individual finger prints we all have our own smell. This is determined by your genes, and can be used by other animals to identify individuals.

4. An individual blood cell takes about 60 seconds to make a complete circuit of the body. 

The average heart pumps about 70ml of blood out with each beat and a healthy heart beats around 70 times a minute.

5. By the time you go to bed at night you are about 1 cm shorter than when you woke up that morning.

This is because the cartilage between your bones is compressed throughout the day.

6. Nerve impulses to and from the brain can travel as fast as 250 miles per hour. 

A nerve impulse is an electrical signal that sends messages to the brain when the nerve is triggered by a stimulus. It is really important that they travel fast, for example, if you burn your finger it’s important that your brain gets the message to stop touching it quickly.nerves

7. There are as many hairs per square inch on your body as a chimpanzee.

Humans are not quite the naked apes that we’re made out to be. We have lots of hair, but on most of us it’s not obvious as a majority of the hairs are too fine or light to be seen.

8. The human body is estimated to have 60,000 miles of blood vessels.

To put that in perspective, the distance around the earth is about 25,000 miles, so your blood vessels could travel more than two times around the Earth if laid out.blood-vessels

9. Babies are always born with blue eyes.

The colour of your eyes depends on the genes you get from your parents, but at birth most babies appear to have blue eyes. The reason behind this is the pigment melanin. The melanin in a newborn’s eyes often needs time after birth to be fully deposited or to be darkened by exposure to ultraviolet light, later revealing the baby’s true eye colour.

10. Every day an adult body produces 300 billion new cells.

Your body not only needs energy to keep your organs up and running but also to constantly repair and build new cells to form the building blocks of your body itself.

Exoplanet discovery

Recently NASA have found the TRAPPIST-1 Solar System (named after the TRAnsmitting Planets and Plantisemals I Small Telescope). It is 40 light years away in the constellation of Aquarius and has seven Earth size Exoplanets (planets that orbit a star that isn’t the Sun) that have the potential to support life.

This is a big discovery as it is the largest amount of Earth sized planets ever found around a single star and it might help in the search for life on other planets. trappist

How did they find the TRAPPIST-1 Solar System?

  • The Star in the centre of the solar system glows brightest in infra-red light which can’t be detected by the human eye
  • The infra red light was detected by an infra red telescope called the Spitzer. This telescope is in space and follows the orbit of the Earth.
  • The radiation (light) detected from the TRAPPIST-1 star would periodically dim and then brighten again; this could show that a planet could be passing in front of the star.
  • The dips in light were not always the same amount, showing that there were actually seven exoplanets orbiting the star.
  • NASA used the dips in radiation to calculate the size of each planet in the solar system.
  • Space in between the dips in radiation means they can work out how it takes for a planet to orbit the star.
  • The planets were found to be very close together with orbits that interfere with each other due to gravity.
  • They used the estimated size of the planets to work out what the density of each planet is, to work out what the planet might be made of.
  • All seven planets may be suitable of supporting liquid water, with three in the habitable zone capable of having oceans.
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The Spitzer Telescope

What next?

It’s really rare to find this many planets that may support life in one solar system so its important to find out more about them. NASA are going to use transmission spectroscopy to study the composition of the seven exoplanets. This is a technique that gives information about the chemical composition of a planet and whether a planet has an atmosphere.

They are using more telescopes to study some of the other ultracool dwarf stars (like TRAPPIST-1), to see if they also have exoplanets that could support life.

#TryThisTuesday: Guess The Flavour

For this Try This Tuesday all you will need is some starburst or chewy fruit sweets.img_4490

Close your eyes and pick a starburst at random without looking. Unwrap it with your eyes closed.

Hold your nose and eat the starburst, make sure you keep holding your nose the whole time.

Can you guess the flavour without looking at the colour of the sweet or the wrapper? You might get some of them wrong!

If you let go of your nose halfway through chewing, you might suddenly be able to taste the flavour.

The Science

Smell and taste are really closely linked, so it is really hard to guess the flavour of the starburst when you hold your nose. About 90% of what we taste is due to smell. Both senses use similar receptors and rely on the same molecules to send messages to the brain about what you can taste and smell. Flavour is actually a mix of taste, smell, texture and other cues like temperature.

It is also important to close your eyes when you eat the starburst, as you can make unconscious links between colour and flavour. Our brain is really good at picking up associations such as a purple coloured sweet is likely to taste of blackcurrant. When the colour makes us expect something to taste a certain way, we taste what we expect unless it’s really different.

This colour association affects some people worse than others,  the pathways to the brain can get crossed over causing synaethesia. This might mean that when they see yellow – they taste lemon.

#TryThisTuesday: Making coins shiny again

New coins are always bright and shiny but they quickly become dull and tarnished. Today we are going to make our coins shiny again!

You will need 100ml of vinegar, some tarnished copper coins and a bowl.vinegar

Pour the vinegar into the bowl and add the salt. Mix until the salt is dissolved.

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Try dipping a coin in and holding it there for 5 minutes. See how half becomes really shiny!

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Put all your coins in and leave for 30 minutes. If you put lots of coins in the vinegar may turn green.img_4337

Make sure you rinse all the coins with clean water.

The Science

Coins become dirty due to oxygen in the air reacting with the metal to form copper oxide. They become darker as they age as the oxide layer increases. Vinegar is an acid (acetic acid) which can be used to clean up surfaces and remove the unwanted oxides. Acids release positively charged hydrogen atoms, also known as Hydrogen ions (H+) which react with the negatively charged oxygen in copper oxide and produce water (H2O). The copper that was linked to the oxygen dissolves leaving a nice shiny surface.

If your vinegar turned green this is due to all the copper dissolving and producing copper acetate.

Real World Applications

Iron that is used to make cars, trucks and boats can also react with the oxygen in the air and oxidise, producing rust. If a car gets rusty, mechanics can use phosphoric acid  to remove it. It reacts with the rust, removing the oxide and replacing it with a layer of iron phosphate. This also protects the metal from rusting further.

Phosphoric acid is also found in coca cola, which is why it is so good at dissolving your teeth!

#TryThisTuesday: Oil and Water

For this experiment all you will need is a clear bottle or jar with a lid, water, cooking oil and some washing up liquid.

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Fill the water bottle half full with water.

Pour about 100ml of oil in to the bottle and observe what happens.

The oil should float on the water. Try and mix them together or challenge other people to mix them! It is impossible, the oil and water always separate out again.

Add a squeeze of washing up liquid to the bottle and shake. The oil and water now mix together.

The Science

Oil is less dense than water so floats on top. Oil and water don’t mix together as the water molecules are more attracted to each other than the oil molecules. Oil molecules are hydrophobic or ‘water-fearing’.

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Washing up liquid molecules are attracted to both water and oil. When you add a squirt in, one end of the washing up liquid molecule attaches to a water molecule and the other end attaches to an oil molecule. This creates a mix of water with oil droplets spread throughout it. This is because one end of the washing up liquid molecule is hydrophobic (water fearing) and one is hydrophilic (water loving).

The washing up liquid acts as a stabiliser and creates an emulsion. This is a mixture of two liquids that wouldn’t normally mix.

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Real Life Applications

We use washing up liquid when we are washing up as it attaches to the oil on the dirty dishes and lifts it off into the water.

Animals that live in the ocean also stay warm by producing an oily substance on their fur or feathers which keeps the cold water away from their skin.