Eat your greens! No more sweets! Drink your milk! No fizzy drinks! Parents are always telling us what to eat but why? Investigate food packaging to find out which foods contain lots of sugar or plenty of good stuff like calcium and fibre. If you have access to the internet, you can experiment with making the healthiest and unhealthiest meals on the McDonalds nutrition calculator. Try out these investigations at home to see what happens if we don’t have enough calcium in our diet or eat too much sugar.

A trip to the dentist

Firstly, let’s look at what different drinks do to our teeth. If you can convince the tooth fairy to leave your teeth behind in the name of science, you can use real teeth. Otherwise, hard boiled eggs are a good substitute*. Pop each one in a plastic cup with a different drink; sugary cola, sugar-free cola, orange juice, fizzy water, tap water, anything you like. If you really want to see what acid does to your teeth, try putting one in vinegar! You might not think that you’d drink vinegar but bacteria in your mouth turn sugar to acid, so sugary things end up being acid in your mouth. This is why it is so important to brush your teeth! Leave the teeth or eggs in the drink for a week and then have a look for any changes.

Bendy bones

Want to see what happens to bones when they don’t have calcium in? Try bending a clean chicken bone to see how stiff it is, then pop it in vinegar for three days. Rinse it off and try bending it, has it gone all rubbery? Can you explain why?

*Note for super scientists: are eggs really a good substitute for teeth? Of course your teeth are much stronger than the eggshells but they are made of a similar material. The egg shells contain mainly calcium carbonate while tooth enamel is mainly calcium phosphate but both dissolve in acid.

You can find more cool experiments on our Home Science page…or book a Fab Scientist to visit your birthday party or school for lots of whizz-popping science fun!

Lava lamps work by taking two substances that don’t mix (usually wax and water) and then heating it to make the ‘lava’ move around. This version doesn’t need wax or heat, just cooking oil, coloured water and a bit of chemistry.

You will need:

•       1 empty plastic bottle (500ml is a good size, still water bottles work best as they have a flat bottom!).

•       Water

•       Food colouring

•       Oil (any vegetable oil will do)

•       Fizzy tablets (soluble vitamin C, cheap versions from a pound shop are perfect!)

•       Small light or torch (pound shop good for this too!)

•       A tray to catch any spillages

First we need to assemble the lava lamp. Stand the bottle on the tray and half fill with water, pop a few drops of food colouring in until you’re happy with the colour. Next, pour in the oil, nearly up to the top (you might need a funnel and a grown-up for this bit!). Leave it to settle for a few minutes, when all the oil is at the top it is ready.

Now to make it move. Drop in a small piece of a fizzy tablet and watch what happens. You should see the bubbles carrying the coloured water up through the oil. You can stand the bottle (carefully!) on a small light or hold a torch underneath it for a real lava lamp effect.

If you want to keep it for another day you can put the lid on … but you MUST wait for it to stop fizzing first. If you put the lid on too soon gas will build up and it could be dangerous.

So how does this work? Oil and water won’t mix because oil is hydrophobic (this means it does NOT like water). The fizzy tablet reacts with the water to make carbon dioxide gas (just like the vinegar and bicarbonate of soda experiments). These bubbles of gas are less dense, basically lighter, than the oil so can bubble up to the top.

You can find lots of experiments to try on our Home Science page…or invite a Fab Scientist to your birthday party or school for more cool science fun!

Oobleck is simple to make but the most messy fun you can have with your kitchen ingredients. All you need is some cornflour and water, about a cup of water mixed with a cup and a half of cornflour works well. You can add a bit of food colouring if you like. Green is slimetastic but go with any colours you fancy, pink and glittery can be lots of fun.

Now to experiment…

Try to decide if the Oobleck is a solid or a liquid. Try to press it hard, solid or liquid? Try pouring it, solid or liquid? It’s actually neither, it has a fancy scientific name of a ‘non-Newtonian fluid’, this means it can behave like either. Try stabbing it hard with a spoon, suddenly it’s solid, let the spoon rest on top and it sinks. Weird, huh? You can squeeze it into a ball, it feels all hard but as soon as you let go (or hand it to an unsuspecting victim!) it will collapse and go runny. Make up your own experiments, get your hands in it, get gooey and have fun. When you’re done, leave it to dry and keep for another day (don’t use it in the gravy though!).

Good vibrations

The Oobleck gets even more odd if you get them vibrating. I’ve put some on an old speaker (covered in clingfilm) and played some loud music through it. If you get the right sounds, the oobleck will start to jump and dance about. There is a video on our Facebook page if you want to see this without risking your speakers! There are also some amazing videos on YouTube of people who have taken the oobleck experimenting to the extreme by filling whole swimming pools with it!

So what’s going on?

The tiny bits of cornflour have jagged edges, when you press them together they get stuck and can’t move past each other, so you have a solid. If you stop pressing, they come unstuck and can flow again like a liquid.

There are lots more home science experiments to try on our Home Science page. Or invite a Fab Scientist to your birthday party or school and we’ll bring all the kit and take away the mess!

Check out any toy shop for a big selection of science kits and toys…there are so many to choose from! But which ones will keep your young scientists excited and engaged beyond Christmas or their birthday? Here are our top picks:

Hot Wires electronics set by John Adams – around £49.99

We love this kit! It is immediately accessible; anyone with no prior knowledge of electronics can make something that works within minutes of opening the box. There are so many more complex things to try as you build confidence and infinite possibilities to test out your own ideas. Everything fits together easily, making experimenting and rebuilding and (we particularly love this as we are geeks) all of the components have the circuit symbols on! Top tip: The John Adams website sells all the pieces as spares at very reasonable prices. Remember this when your budding electronic engineer loses the yellow spinner (you might want to buy two at a time). The kit itself can be found in most large toy shops or online retailers.

Virtuali-tee T-shirt by Curiscope – £24.99

We use an adult-sized version of this T-shirt for our Brilliant Bodies camps and workshops and it goes down a storm! It is just a blue T-shirt with a funny pixelated skeleton pattern on the front, you might think it does not exactly look exciting. However, download the free app on your phone or tablet, point it at the T-shirt and you can see inside your own body! Of course, it’s not really x-ray vision but it looks pretty real; it’s 3D, it moves with your body and even has a beating heart. We hook it up to a projector when we are working with big groups but it’s just as effective on a small screen when you only need one or two people to be able to see it. You can buy direct from Curiscope or other online retailers.

Whizz Pop Bang magazine – £39.99 annual subscription

OK, so this isn’t a toy but Whizz Pop Bang inspires our kids to try out more science experiments than any chemistry set we’ve ever bought! This magazine was created by the fabulous Jenny Inglis (who used to be a science presenter on Blue Peter) and it is full of interesting facts, experiments to try and interviews with real scientists. They don’t allow any advertising in the magazine, it doesn’t come with any plastic tat stuck to the front and it’s even delivered in a paper envelope. You can subscribe (if it’s for Christmas they often do offers that include a free book or similar) or buy individual copies for £3.99. Each month is a different theme so you may want to search through the back catalogue for titles that will really grab your young scientist’s imagination…Ploptastic Poo for example! Subscriptions and back issues are all available direct from Whizz Pop Bang.

Natural History Museum pocket microscope – £12 (+P&P)

Many of our activities at Fab Science events need us to see things that are very small, from bug-hunting to analysing fibres in Fab Forensics. Over time, we have spent a small fortune on various microscopes that didn’t quite fit the bill…until we found this one. We have ten of these and they have been thoroughly road-tested by our young Fab Scientists. They have been used indoors, outdoors, in mud, in bright light, in dim light, upside-down, sitting quietly, running around…and they are all still going! They will take a normal microscope slide but can also be used without the stage so you can put it straight onto the surface that you want to look at. The magnification isn’t huge at x40 but this is plenty to make everyday objects way more interesting. You can buy direct from the Natural History Museum website or usual online retailers.

Chemical Elements Top Trumps – £6

If your child loves Top Trumps and loves science…this is a perfect stocking filler! The set was designed by the Royal Society for Chemistry so the numbers are real (no ‘Cool Ratings’ here) and players learn about the elements while enjoying the game. Each card even includes interesting facts as well the chemical symbol but is bright, colourful and fun.

You can buy direct from the RSC bookshop or usual retailers.

Make your own chemistry kit

We’ve tested a few chemistry kits and haven’t yet found one that really excites us. There is often too much plastic packaging and not enough actual stuff to do anything! We’re happy to be proven wrong though so do let us know if there’s one we’ve missed. If you have a little chemist at home who wants to turn your kitchen into a lab, here’s a list of basics to get them going.

• Goggles – kids ones tend to be a bit rubbish, just buy grown up ones (from a hardware store) with an elasticated band that can be adjusted. Get a couple of pairs so they can experiment with a friend (or for when you want to join in)
• Plastic test tubes (6-10) and a rack to put them in
• Beakers
• Small measuring jug
• Plastic pipettes
• Funnels
• A big tray to catch any spills 🙂
• Things from around the house such as old spoons, empty plastic bottles, balloons, squeezy bottles etc.

All of this can found in many places locally or online. Strangely, we’ve found the best supplier of reasonably priced test tubes, racks, beakers etc is Cream Supplies. They do ‘molecular gastronomy’ equipment but it’s perfect for kitchen science! For ideas on experiments to try out, see our ‘home science‘ pages.

Fun with crystals

If you look closely at sugar or salt, you will see it is made up of lots of little crystals. We can ‘grow’ bigger crystals if we start from scratch and let them form slowly. So how do we make a crystal from scratch? We need to dissolve the salt or sugar and then let it recrystalise. You can try out these two experiments to make some rock candy and geodes. Both of these involve boiling water so definitely one for some grown-up help.

Rock candy

Heat a cupful of water in a pan until it is boiling. Then start adding sugar. Stir, add more sugar, stir, add more sugar, stir…you get the idea! Keep going until you cannot get any more to dissolve, this should be at least two cupfuls. This is called a saturated solution. Let the mixture cool down for around 20 minutes then pour into a tall glass. When the solution cools we say it supersaturated, this means it now has more sugar than it can normally hold. It’s ready to start growing crystals! If you hang a bamboo skewer into the glass (use a clothes-peg to keep it in place), crystals of sugar will start to form on the skewer. Remember we need SLOW formation so it will take a few days, perhaps even a week, be patient! It’s really important that it is left undisturbed for this time so put it somewhere out of the way.

Geodes

Geodes are mineral crystals found inside rocks, we can make our own inside eggshells. Make sure the eggshells are perfectly clean and the membrane has come away from the inside. Make a saturated solution like you did before, you can use sugar or try table salt or Epsom salts, then add a little food colouring. Pop the shells in an egg box and fill with this solution, the fuller the better but make sure they won’t spill! Leave them somewhere safe to evaporate and in a few days you should see the geodes form!

Crystals in nature

Crystals form in nature when some things become solids. This can be rocks that were molten (lava) or minerals that were dissolved in water. Molten rocks will solidify as they cool, dissolved mineral will crystalise as the water evaporates.

The size of the crystals depends on the time that they take to form. Fast=small, slow=big. Igneous rocks (ones that are made from lava or magma) might have small crystals if they came from a volcano as they would cool quickly in the air. Sometimes igneous rocks can be made slowly underground and we can often see larger crystals in these. Geodes come from dissolved minerals seeping into gaps in other rocks, the water evaporates soooo slowly that we get beautiful big crystals. You can try putting your egg geodes in different places when they are evaporating, perhaps one on a radiator, one on a windowsill and one somewhere cold. Just make sure they’re not going to get knocked over!