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Doc. Yard's

... kitchen science

Doc.Yard is tucked away, self-isolating in his secret lab but he’s worried that his budding students are going to forget their passion for science. To help curb the boredom at home, Doc will be releasing a series of easy to follow kitchen experiments for everyone to try at home.

A new experiment will be released each week on our social media accounts. Don’t forget to share your results using #DocYard

Week 1: Ooblek

... is it a liquid or a solid?

Oobleck is a non-newtonian fluid. It acts like a liquid when being poured but like a solid when a force acts on it. Make it into a ball, release the pressure and it will ooze through your fingers – make enough and might be able to walk on it!

You will need :

  • 1 cup of water
  • 1 – 2 cup of cornflour
  • 1 bowl
  • 1 mixing spoon
  • Food colouring (if desired)

Method:

Place 1 cup of water in a bowl. Add ½ cup of cornflour and stir in. Add small amounts of the remaining corn flour and repeat until the mixture becomes difficult to stir quickly. You might not need all of the cornflour. If the mixture becomes a solid add a little more water.

Your aim is to get a consistency which is hard when you stir it quickly, but runny when you stir it slowly.

Add a few drops of food colouring if you want to make it a fun colour.

 

The Science Bit what’s going on?

‘Oobleck’ changes its properties from a liquid to a solid by adding pressure. Usually normal solids and liquids require heat to do this, but a non-Newtonian fluid uses pressure to do this. The particles within this mixture are suspended in a way that make them very close to being both liquid and solid.

If you stir quickly the added pressure forces the particles closer together and they form a solid structure. When you stir slowly the particles have time to ‘get out of the way’ and the spoon passes by as if in a liquid.

What next?

If you get a really good Oobleck consistency, you can give it a squeeze and pick it up in your fingers and hands like putty, but a soon as you stop squeezing it’ll run through your fingers like milk. Lots of messy fun!

If you’ve ever made custard from a powder – it contains cornflour so behaves in the same way.

A groups of English scientists on ‘Brainiac’ filled a swimming pool full of custard, and one of them was able to walk across the surface without sinking – Amazing!

Week 2: Going Underground

... the great bean experiment

An experiment to show the germination process of a seed to plant.

You will need :

  • 2 runner bean seeds (or other seeds are ok)
  • 1 glass/plastic jar (no lid)
  • 1 small plant pot
  • Compost
  • Paper towel
  • Black card
  • Scissors
  • Sticky tape

Method:

You are going to plant one seed as normal, then plant one so that you can see the process a seed goes through to change to a plant.

First place compost in a small plant pot and poke a 3cm deep hole. Drop in one of the beans, cover with compost and add water until the soil is moist. Some may come out of the bottom of the pot, which is fine. Place this on a warm windowsill. You will need to water this every few days to keep the soil moist. You will see things begin to grow after 1-2 weeks.

 

 

Second, cut a piece of paper towel to the height of the jar and wrap it around the inside of the jar. It is ok if the paper towel overlaps. Place the second bean between the paper towel and jar, about half way down the jar is best. If it keeps dropping to the bottom of the jar, pinch the paper towel to create a little ridge to hold it in place. It’s important that it is around half-way up the jar. Not at the top, or the bottom.

Now add water to the middle of the jar. About 1cm deep is fine. The paper towel will draw the water up to the bean in a process called ‘capillary action’. The holes in the paper towel pull the water upwards against gravity.

Now make a tube of a black paper so that it surrounds the jar and stick with a piece of tape. Place this in a warm dark place. Check it each day. Over the next week, you will see a root first reaching down to the water, then you will see a shoot moving upwards until it gets to the top of the jar.

 

The Science Bitwhat’s going on?

How can a bean possibly grow without soil? Actually, all of the food that a new plant needs to germinate (start to grow) is stored within the shell of the seed – in this case the bean. The water triggers the growing process. You may have seen this if you have ever grown cress on a tissue, or a carrot top in a saucer.

The first stage is to send out a root. How does the seed know where the water is? How does it know how to send the roots downwards and the shoot upwards? This is the clever bit! There is no light under the soil, so it doesn’t know where the sunlight will be. It actually uses gravity. It feels the pull of gravity on the roots and sends them downwards. It then sends the shoot the opposite way, which means that it eventually pops up out of the soil. So be re-assured – it is impossible to plant a seed ‘upside down’!

Did you know?

Many growers now use a new scientific method of growing plants where they don’t use soil at all. This method uses hydroponics. As long as the plant has water, sunlight and a few dissolved minerals, it can create its own food. It doesn’t eat soil – it uses sunlight in a process called photosynthesis.

Week 3: Under the sea

... the science of submarines

This week Doc has not one but two experiments showing the principles of a submarine – inspired by our resident submarine, HMS Ocelot. 

Experiment 1: Raisin Submarines

You will need : 

  • 1 clear glass / jar.
  • Bottle of fizzy drink (transparent works best). 
  • 1raisins/sultanas. 

Method: 

Pour the fizzy liquid into your glass or jar. Be careful not to over fill it. Leave a gap at the top. Add 10 raisins into the glass. The raisins should fall to the bottom. 

 

 

Watch the raisins carefully over a few minutes. You should see them begin to float up towards the surface at different times. When they get to the top they will release the fizz then drop to the bottom of the glass again. This should be repeated by the different raisins at different times. You have made mini submarines! 

 

 

The Science Bit what’s going on? 

The fizzy drink contains a gas called Carbon Dioxide (CO2). The surface of a raisin is rough, so will trap any gas forming at the surface. As the amount of gas trapped increases, it will displace more liquid, increasing a force called upthrust being exerted on the raisin. It becomes more buoyant and rises to the surface. When the raisin gets to the surface, the bubbles pop, the gas is released, so the raisin sinks back to the bottom of the glass. 

Did you know HMS Ocelot used the exact same science to move up and down in the water when on her missions? She would fill her ballast tanks with air to go up, but release the air in her ballast tanks (letting in sea water) to go down. 


 

Experiment 2: Underwater Diving Bell 

This at first this seems a little bit like magic…. 

What you’ll need:

  • 1 sink of water.
  • glass.
  • large tissue or piece of kitchen paper.

Method: 

Place the screwedup tissue or paper towel into a glass. Make sure it is wedged at the bottom of the glass, so that it doesn’t fall out when you turn the glass upside down. 

Fill a sink with water, so that it is deeper than the height of your glass. Now carefully turn the glass upside down so that the tissue is at the top and rim is at the bottom. Slowly lower it into the water. Keep lowering it, until it is completely submerged (under water). You may get the odd bubble escaping from the glass, but that’s fine, don’t let too much trapped air escape.

Once you are sure that the glass has been completely submerged, lift it up slowly out of the water. You will find that the tissue in the glass is completely dry – even though it has been for a trip underwater! 

 

The Science Bit … what’s going on? 

It’s not magic – it’s pure Science. When the glass it submerged under the water, a body of air is trapped within the glass, as well as the tissue. Below the surface, the water in the sink is pushing trying to get into the glass, but the trapped air is pushing back. This is called air pressure. It is strong enough to keep the water out of the glass. This is why the tissue stays dry – even though it has been underwater!  

Before Submarines existedopen bottomed machines called Diving Bells were used to transport people to the sea floor. Eventually ‘Closed Diving Bells’ were developed that were sealed all around and could be lowered into deeper water. Vessels like this are still used today to rescue crews from submarines in difficulty. 

 

Week 4: Ships and Shipmates

... the power of pressure

An experiment to show the power of air pressure.

You will need :

  • 1 balloon.
  • 1 plastic drinks bottle (no lid).
  • 1 pair of scissors or pen to pierce a hole.

Method:

First – blow up the balloon but don’t tie it. This will show the amount of effort needed to inflate the balloon using your own lung pressure. Now deflate your balloon (let the air out).

Next – Place the balloon inside the bottle, making sure to keep the neck (the bit you blow into) on the outside. Wrap the neck of the balloon around the neck of the bottle. Now try and inflate the balloon (blow it up). You should find that it is impossible to inflate however hard you blow.

 

Using adult help if necessary, place a small hole in the bottom of the bottle with a pair of scissors or pen. Now it should be possible to blow the balloon up.

 

Once you have blown up the balloon inside the bottle, cover the hole in the bottom. When you stop blowing, the balloon will remain inflated inside the bottle…even with the neck of the balloon open. Only when you uncover the hole will the balloon deflate!

 

The Science Bitwhat’s going on?

When you blow up a balloon you increase the air pressure inside the rubber skin and it inflates (if you let go it escapes and goes flying off).

When the balloon is stretched around the bottle neck, the air around the balloon is trapped inside the bottle. As you try to inflate the balloon, the trapped air in the bottle pushes back – it can’t escape. The balloon can’t inflate however hard you try to blow, the pressure from the air trapped in the bottle is too strong.

When you piece the bottom of the bottle the trapped air now has a way to escape, so it is possible to blow up the balloon, although it may be a little tougher. Now with the balloon inflated, when you cover the hole – air cannot get back into the bottle, so the balloon stays inflated. When you uncover the hole, air rushes back in and the balloon deflates.

Did you know?

If you take a sealed bottle to the bottom of the ocean the water pressure increases and crushes the bottle. If you take a sealed bottle to the top of the mountain where the air is thinner (less air pressure) the air pressure in the bottle is greater than outside. The bottle expands and can split. Mountain walkers with sealed packets of crisps in their backpacks often find the packets expand and sometimes explode! Very messy!

Week 5: Secrets & Spies

... pinhole camera & mirror writing

Two experiments showing how light travels in straight lines.

Experiment 1: Pinhole Camera

A Pinhole Camera- or ‘camera obscura’ as it’s sometimes known, will allow you to project an image onto a screen through a tiny hole (aperture). This demonstrates how real spy cameras work.

You will need:

  • 1 empty crisp tube
  • Scissors
  • Sellotape
  • Baking paper
  • Kitchen Foil
  • 1 drawing pin


Method:

Remove the lid of the crisp tube. Measure a line around the tube 5cm from the aluminium base. With adult help, cut the tube along the line so that you have a short tube with a base and a long tube open at both ends.

Now, use the lid to draw a circle on the baking paper and cut this out. Place the circle of paper inside the lid and tape it in place. This will be the screen where the camera’s image will be projected onto. Place the lid on the end of the short tube, opposite the base. This will create a sealed short tube.

Use the drawing pin to poke a tiny pinhole in the centre of aluminium base. Try to get it as close to the centre as you can. This is where the camera gets its name.

Next, tape the hollow long tube to the short tube so that the lid remains in the middle, and the pinhole you just made is at one end. You should now have a full-length crisp tube, with the lid (screen) in the middle and the pinhole (aperture) at one end.

It is important to have no light entering the tube, apart from through the pinhole and viewing end, so now wrap kitchen foil around the tube a few times then stick it with tape.

Take the pin hole camera outside or to a window where it is light. Looking down the tube you will be able to see the image on the lid, but it will be upside down!

The Science Bit … what’s going on?

Light travels in straight lines, so as it passes through the tiny pin hole it continues on a straight path. That means that things at the top of the image of the outside world are now are at the bottom of the screen. Things at the bottom outside are now at the top. This is how a camera captures an image on a negative – upside down. A mirror in the view finder flips it the right way up.

Did you know … that is how our eye works? Our pupil lets in the light, and the image appears at the back of our eye upside down. It’s our brain that turns it the right way around!

2nd Experiment – Mirror Writing

If you want to be a super-spy then send a secret message by writing it backwards!

You will need:

  • Pencil
  • Paper
  • Small Mirror

Method:

Holding the mirror next to your paper, begin to write your message – starting on the opposite side to the one you normally start with. Looking into the mirror, begin to write your message.

Be careful with tricky letters like ‘y’ and ‘s’ which will be the other way around. It’ll take a bit of practise. Your writing should be able to be read in the mirror but look backwards on your page.

Now give your message to a friendly spy – the receiver can use a mirror to decode what you have written.


The Science Bit … what’s going on?

A reflective surface, like a mirror, allows light to bounce off. Since we know light travels in straight lines – just like in the pinhole camera experiment – the mirror reflects an image in reverse. The light enters the mirror at the ‘angle of incidence’ then bounces off at the same angle – ‘angle of reflection’. The parts of a letter closest to the mirror will be appear close in the reflection. Parts of the letter further away from the mirror will be reflected deeper into the mirror. This means that the letter is reversed.

Did you know … HM Submarine Ocelot has two mirrors inside the Periscope? This means that the image you see at the eye piece is the correct way around – not in reverse.

Week 6: Levitation

Make a ball magically levitate in the air.

You will need :

  • 1 table tennis ball
  • 1 hair dryer.

Method:

Turn the hair dryer to a cold setting and rotate it to face the ceiling. Turn on the hair dryer so that it is blowing a vertical column of air upwards.

Gently place the table tennis ball within the stream of air.

 

You will see that the ball levitates within the column of air – moving neither left or right. Move the hair dryer to the left or right, forward or backwards. The ball travels too, remaining in the column of air.

Now here is the cool bit – very slowly and carefully rotate the hair dryer to the left or right. The table tennis ball will remain in the air stream and levitate above the floor. You can rotate the hair dryer up to a maximum of 45 degrees from vertical (in between vertical and horizontal).

 

 

The Science Bit … what’s going on?

The body of air travelling from the hair dryer is travelling at a constant speed and therefore pressure. This force pushes the ball upwards overcoming the force of gravity – it levitates!

As the air passes by the ball it has a greater distance to travel. The air particles spread out and are forced to travel further. This reduces the air pressure at the surface of the ball. All of the rest of the air in the room is at an even pressure, so presses against the sides of the ball, holding everything in place. Even when the ball is at a 45 degree angle, it is still within the moving air stream. If you rotate past 45 degrees then the force of gravity is greater than the upward force of air pressure holding the ball in place. Gravity wins and pulls the ball to the ground.

What next?

You could try this experiment using larger balls or even a balloon. It is important that you choose light balls, so that the hair dryer is strong enough to overcome gravity.

Try placing more than one ball in the air stream can you make two or three levitate?

If you have a leaf blower then it is possible to do this experiment with a beach ball!

Did you know that the 18th century scientist Daniel Bernoulli explained the phenomenon? Although we’re pretty sure he didn’t have a hair dryer!

Week 7: Eggstra Strong Eggs

An experiment to show the natural strength within a thin egg shell.

You will need :

  • 2 eggs
  • 1 knife to crack the eggs
  • 1 bowl
  • Scissors
  • Paper towel
  • Several books.

Method:

With adults help use a knife to carefully crack an eggshell in half, emptying the contents of the egg into a bowl. Try to break the shell so that you have two equal halves. Repeat this with the second eggshell. The eggs in the bowl can be saved to cook later.

Carefully rinse your four halves of eggshell to remove any left-over egg whites and gently dry them with a piece of paper towel. You can trim the eggshell halves with a pair of scissors to get them roughly the same size if you need to. You can see they are very delicate and could break easily.

Place all four egg halves on a flat surface with their points facing upwards, broken parts resting on the surface.

Next carefully and gently place one book on the top of the eggs, trying to spread the weight of the book evenly across the eggs. You will see that the eggs hold up the weight of the book easily.

Next add a second book on top of the first, again gently being careful to place the book centrally on the first.

This can be repeated over and over again until the eggs finally give way and are crushed below the pile of books.

You will be amazed at how many books the eggshells will hold before they give way.

The Science Bit … what’s going on?

Gravity pulls all objects to the ground. The weight of an object is called its ‘mass’ often measured in grams or kilograms.

Birds eggs have a natural strength from top to bottom but are very week from side to side. That’s why it is easy to break an egg by squeezing it from the sides, but really difficult to crush it from point to base.

When you place a book on the points of the four eggshells, they are able to take the mass of the book resting on it and transfer that down the walls of the eggshell down to the surface. The weight is shared across the walls of the egg. The more eggs you have – the more weight can be shared between the shells. When you add more books, the extra mass is also transferred down the walls of the egg to the surface. This is continued until the mass is too great and the shells fail (get crushed). You will notice that one of the eggshells gives way first, transferring all of the weight to the other three, they then quickly follow, and all get crushed under the books.

The shell of an egg is like an arch. This scientific principle of weight transferal allows arch bridges to be built. When a heavy car goes over the top, the extra mass is transferred down the sides of the arch to the ground. Also eggshells are so strong that if you had enough of them, they will support a person standing on top?! Just don’t lay them on their sides…stand them up, you’ve shown they are stronger that way!

Did you know that at the Dockyard we have a beautiful building called Slip 3 where ships used to be constructed? The roof is a magnificent arch of timbers designed and built by shipwrights in the mid 19th century. The weight of the heavy roof is transferred down the support posts holding up the roof. This meant that they could design a larger, heavier, wider roof to span the gap below.

classical music concert

 

Week 8: Magic Pencil

An experiment to show how light travels through different liquids in different ways.

You will need:

  • 1 wide glass or glass jar
  • Water
  • Cooking oil
  • Some liquid honey or syrup
  • A pencil.

Method:

Pour water into your glass or jar until it is half full. Place the pencil into the water at a diagonal (45 degrees is best) and look from the side. You will see that the pencil seems to bend and grow slightly in size as it enters the water. Now remove the pencil.

Next, pour cooking oil on top of the water so that you have a thick layer. You will notice that the oil sits on top of the water. There may be bubbles trapped between the water and oil, so leave it for a few minutes to settle.

Place you pencil in the jar again at a diagonal as before and again look from the side. This time you will see that the pencil looks like it has broken when entering the oil, but repairs itself as it enters the water. Now remove the pencil again – see it is not broken- it is still in one piece.

Is this magic? …No, it’s science!

The Science Bitwhat’s going on?

When light travels through a liquid it is ‘diffracted’ or bent slightly. Water also helps to magnify light like a lens, so when you place the pencil in at an angle it bends a little and grows a little thicker.

Different liquids have different densities – some are ‘gloopier’ or thicker than others. Oil is less dense than water so it sits on top. Even if you add a lid and shake vigorously, they will still separate into two layers and not mix.

To explore liquid densities, now add a different liquid to the jar by adding the liquid honey or syrup. You will see that it is denser (thicker) than water so sinks to the bottom of the jar. The water sits on top of the syrup and the oil sits on top of the water. You have shown three different liquids with three different densities.


Did you know?

When water freezes into ice, its density is lowered, so ice will float on top of water, however only around 1/10 of an ice cube floats above the water. 9/10 floats below the surface. When HMS Cavalier travelled around the Arctic ocean during the second world war protecting the Allied convoys, the sailors had to be careful to steer well clear of icebergs, because they were much bigger that they appeared and could have easily damaged the hull.

HMS Cavalier 1945

Week 9: Paper Helicopter

An experiment to explore air resistance.

You will need:

  • 1 sheet of paper (A4 is fine)
  • A paper clip
  • A Pencil
  • A ruler
  • A pair of scissors.

Method:

Use your pencil, ruler and scissors to cut a rectangle with a length (top to bottom) double the measurement of the width (side to side). I measured and cut a rectangle with sides 18cm long and 9cm wide.

Next, half-way down the long side, make two cuts in from the edge 3cm long (a third of the width). This means you will have a 3cm gap between the cuts.

Fold the two sides in so that you have a bottom half which is a third the width of the top half. This creates the body of the helicopter.

Fold up the base 2cm and secure with a paper clip.

Now, draw a line down the centre of the top half, and cut along this line, but stop 2 cm before the middle line. This creates the blades.

Fold one blade forwards and the other backwards.

You now have completed your paper helicopter ready for testing.

Drop the helicopter from above head height. It should begin to rotate (spin) and as it spins its rate of decent will decrease (it will fall more slowly).

You can investigate how different sized paper helicopters fall at different speeds.

The Science Bit … what’s going on?

The paper helicopter uses air resistance to slow it down as it falls through the air. The paper clip adds a little weight to make sure that it falls the correct way each time. Because you folded one blade forwards and one backwards, it has created an angle at which the blade ‘attacks’ the air, which causes the spin. As it spins a cushion of air forms below the blades and this slows the helicopter as it falls. Although Gravity pulls everything to the floor, any movement downwards creates air resistance… the air literally gets in the way.

Did you know?

We have a Royal Naval helicopter at the Dockyard. It is a Westland Dragonfly helicopter. It is called a ‘dragonfly’, because its rotor blades can fold back like a dragonfly’s wings. The reason for this is so that they could fit more easily on the deck of a ship.

If you have ever seen a sycamore seed in the autumn, you will see that the shape is like a blade with a weight at the bottom (the seed). It falls just like your paper helicopter. This is an advantage for the tree, because its seeds will fall slowly, allowing them to be blown by the wind. This means that a seed travels further away from the parent plant and grows in a new spot. Nature using air resistance – very clever!

Week 10: Colourful Rainbows

Two experiments exploring paper chromatography and water stratification.

1st Experiment: Paper Chromatography

You will need:

  • 1 paper towel
  • Scissors
  • Ruler
  • Colouring pens (including black)
  • A pencil
  • A jar/glass
  • Sticky tape.

Method:

Cut a strip of paper towel as wide as your jar/glass and a couple of centimetres longer. Place the top of the paper towel around a pencil and stick down with tape. Trim the length of the paper towel so that it is long enough to just touch the bottom of the jar.

Next using the colouring pens, draw small dots of each colour about 2 cm from the base of the paper towel. Add water to the jar so you have about 1/2cm in the base. You want the water level below the height of your colourful dots. Now suspend the paper towel into the jar, so that the end just dips into the water.

Watch the water get ‘sucked’ up the paper towel and pull the ink with it. Each colour should give a different result. You’ll be surprised at what colours go together to make the black.


The Science Bit … what’s going on?

Often the colour of a colouring pen is actually made up of several colours of ink. The paper towel uses capillary action to ‘draw’ the water up to the top. As the water travels past the colourful dots, it dissolves the different ink colours and carries them with it up the paper. Each of the coloured inks have a slightly different density, so the denser (heavier) inks are dropped first lower down and the less dense (lighter) inks are carried further up the paper towel. From this you will be able to see which different coloured inks go together to make up which coloured pen.

2nd Experiment: Skittle rainbows.

You will need:

  • 1 bag of skittles
  • 1 plate
  • Warm water.

Method:

Place a circle of the sweets on a plate. You can choose how many you use. Using more than 10 makes a great effect.

 

With adult help if necessary, carefully slowly pour the warm water in the centre of the circle until the sweets are half covered. Now wait and watch.

You will see the warm water begin to dissolve the colourful shells of the sweets, but they don’t mix. This creates a wonderfully colourful pattern. If you carefully remove the sweets, the pattern will remain on the plate.

 

The Science Bit …what’s going on?

Each of the colourful sweets have food colouring that gives them their bright colours. Each of these food dyes when dissolved in water have slightly different densities. Because the water is at different densities it will not mix together. This scientific process is called ‘water stratification’.

Did you know?

This process also works with different temperatures of water. Have you ever paddled in the sea on a hot day? If so, you may have felt the water at the surface can be warm, while the water down by your toes is a lot cooler. The different temperatures stop the water from mixing because of water stratification.

Around the world currents flow throughout the oceans, warm currents of water from the equator to the poles, and cold water from the poles to the equator. The water doesn’t mix because it is different temperatures.

In the past the sailors of the Royal Navy learnt to use these strong currents to help them travel around the world’s oceans. The historic ships at Chatham, HMS Gannet, HMS Cavalier and HMS Ocelot have sailed in the South Pacific, the Mediterranean, the Arctic, the Baltic Seas and the Red Sea.

HMS Gannet

Week 11: Making Magnets

This experiment explores the two ways to create a magnet at home.

You will need:

  • A fridge magnet
  • 2 paper clips
  • A long nail
  • Some wire (electrical or garden wire)
  • 1 battery

Method:

First – it is possible to create a magnet field around a metallic object by ‘magnetising’ it – with another magnet.

Take a paper clip and gently stroke along the length with a fridge magnet. Always travel the same direction…like you are stroking a pet. If you do this lots, your paper clip will become magnetised and pick up a second paper clip.

If this doesn’t work – try holding the fridge magnet at one end of the paperclip. This will turn the paperclip into a magnet and you will be able to pick up extra paperclips.

Second – It is possible to make something magnetic by adding electricity – this is known as an electromagnet.

Take a length of wire with a metal core. Strip a small amount of plastic coating from each end of the wire so the metal wire inside is ‘bare’. This will give a good contact with the battery.

Now – coil the wire around a metal nail. Wrap it around tightly but leave enough wire at the ends to reach the ends of the battery.

You’ll need an extra pair of hands for this next bit. Ask an adult to hold the ends of the wire to the ends of the battery. When the wire is connected it will be possible to pick up a paperclip on the end of the nail because the nail is now an electromagnet.

When your helper breaks the circuit and removes a wire from the end of the battery, the paperclip will fall. The nail is only an electromagnet when the electricity is flowing down the wire.


The Science Bit … what’s going on?

A fridge magnet is made of a material containing a ferrous material (like iron) that has been magnetised. It will hold its magnetic power. When you stroke a paper clip with a magnet, the electrons within the material line up in one direction, and this creates a magnetic field which can pick up another paperclip. This is a weak magnetic field so it won’t pick up anything heavy.

When electrons pass through a wire a tiny magnetic field is created around the wire. When the wire is coiled around a nail, the tiny magnetic fields join to create a more powerful magnetic field. The greater the electrical power running through the wire, the stronger the electromagnet. When the wire is removed from the battery, the electricity stops flowing through the wire, so the magnetic field disappears. These types of electromagnets can be switched on and off as required.

Did you know?

When the Dockyard began to make metal ships at the end of the 19th century, large sheets of heavy steel were needed to be moved around the Dockyard. It was possible to move these large iron and steel sheets by using electromagnets fitted to cranes. By turning on the power, it turned on the magnet to lift the heavy weight. The magnet could be turned off to drop the sheets where they were needed.

World record worthy bubbles

An experiment to allow you to create giant sized bubbles.

You will need:

Bubble Mixture:

  • Water
  • Glycerine
  • Washing Up Liquid
  • Large Bowl
  • Measuring Jug
  • Teaspoon

Bubble Wand:

  • 2 long sticks
  • String
  • Scissors
  • Tape measure
  • A small weight (nut or washer is perfect)

Method:

For the bubble mixture we use three liquids that combine to form a strong giant bubble. Pour 250ml of washing up liquid into a large bowl. Add 2 tsp of glycerine, this can be easily found in the baking section of supermarkets. Slowly add 1 Litre of water and stir together. You do not want to create bubbles at this stage by mixing it quickly.



When you have mixed the bubble solution together, leave this to rest while you make the bubble wand.

For the Bubble Wand, take two long straight thin sticks – garden canes are best. Cut one length of string 1m long. Cut the next length of string 2m long.



Tie each end of the 1m length of string to the top of each of the two sticks.


Next tie both ends of the 2m piece of string, to the ends of the short string – not the sticks. You need to create a loop of strings like a smiley mouth that the bubble can form within.



Now add a small nut or washer to the middle of the long piece of string to act as a weight.


To create the giant bubbles, take your rested bubble mixture and bubble wand outside.


Place the two sticks of the wand together and dip the string into the bubble mixture, making sure it’s fully submerged (dunked in).

Lift out the string allowing the weight at the bottom to hang freely. Now slowly, carefully separate the sticks to create a bubble within the string. Slowly swing the weight to one side so that you trap air inside the bubble. When you close the sticks back together, it will complete the bubble and your giant bubble will float away.


On windy days, the bubble will create itself!


 

The Science Bit … what’s going on?

Bubbles are great fun! Adding washing up liquid to water will always create small bubbles when you are doing the washing up. However, these will pop easily. If you want to create giant bubbles, you need to add a bit of strength to the mixture. Adding Glycerine to the bubble solution gives the surface of the bubble that extra strength.

When you blow a bubble, it ends up as a perfect sphere (ball shape), that is because the forces within the skin of the bubble are shared equally all around the surface which results in a perfect shape. This is called surface tension.

With larger bubbles there are larger forces acting on the skin, and you can sometimes create a wonky bubble that has trouble becoming a sphere. Often at this stage the skin would rupture, and the bubble would burst. This is where the Glycerine comes in to help. It gives the bubble skin the extra strength it needs to stay together.

How big can you make your giant bubbles?

Did you know?

Many people have attempted to break the Guinness World Record for the world’s largest soap bubble. The current record holder created their bubble in 2019. The largest bubbles are always created using this exact same bubble wand method.

Maybe you could become the next World Record holder?

COVID-19 (Coronavirus)
Notice to Visitors

Chatham Historic Dockyard Trust welcomes the news that museums and visitor attractions are able to reopen to visitors from 4 July.

We are actively planning to welcome visitors back to the Dockyard as soon as we are safely able to do so but this will be some time after 4 July.

We will make a further announcement to confirm the exact date as soon as we can.

In the meantime, much of Dockyard life has never stopped. Master Ropemakers has started operating again and we are taking forward bookings for filming, group travel and hospitality, including weddings. Call the Midwife Official Location Tours will resume shortly.

We would like to thank all our visitors for their understanding during this challenging period.

Last updated: 25 June 2020

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