Candy Crystals and Chocolate Brownies

Although not strictly a supper, these gluten-free brownies are our absolute favourite and whilst you have the sugar out you can set up a little science activity…growing your own crystals.

Our blue sugar crystals after two days

Science Ingredients

  • Sugar
  • Food colour (optional)
  • Hot water
  • Egg cup
  • Small plate
  • Foil

Supper (sort of) Ingredients

  • Sugar
  • 3 eggs
  • Chocolate
  • Ground almonds
  • Butter
  • Salt
  • Vanilla essence
  • Chocolate chips


  • Line a small traybake/cake tin and pre-heat oven to 170°C
  • Melt 225g chocolate and 225g butter in a bowl (I give it a minute in the microwave, stir and repeat till melted)
  • Leave to cool a little whilst you set up your crystals
    • Cover a small plate with foil
    • Half fill an egg cup with hot water
    • Stir in a tsp sugar and a dash of food colour
    • Put a few spoonfuls of the solution onto the plate
    • Pop on the windowsill, or somewhere it won’t get knocked, for a few days
  • Add 150g ground almonds and 200g sugar to 3 beaten eggs
  • Add a pinch of salt, 2 tsp vanilla essence and combine with the chocolate butter mixture
  • Stir in 200g chocolate chips (yes you read that right)
  • Bake for 25-30 mins and leave to cool in the tin

Science in a Sentence

The water from the plate evaporates into the air as water vapour; sugar molecules are left behind and link together to form crystals (molecules arranged in a regular repeating pattern).


The brownies are more like truffles or very dense chocolate cake, they are devine but not even slightly healthy. You can use any type of sugar; we usually use granulated but it works well with caster and demerara and also with dark, softer sugars although the end result is stickier. Once cooked, we cut these into small cubes and keep half in the fridge and freeze half. They are gluten-free but if you need nut-free or don’t have almonds then you can use rice flour or similar instead. You can also leave out the chocolate chips or substitute chopped nuts, dried fruit or mini-marshmallows.

We use a square brownie tray but have also done these in a round cake tin. If your mixture is less than an inch deep, bake for 15 mins then check and cook a little longer if needed. The end result should be slightly risen with a wobble.

Check your crystals each day, you should see crystals appearing after a day or two. Once the first sugar solution has evaporated, you could carefully add another colour to make a crystal garden.

A warm room will speed up seeing crystals but they will be smaller than a cooler room where the crystals have time to grow as the water slowly evaporates.

The Unmixables

Turn your salad dressing into a science experiment…

The Unmixables: Oil and Water

Science Ingredients

  • Oil
  • Vinegar
  • Jar with lid
  • Honey (optional)
  • Coloured washing up liquid (optional)
  • Water coloured with food colouring (optional)
  • Pipette or dropper (optional)

Supper Ingredients

  • Oil
  • Vinegar
  • Honey (optional)
  • Dijon mustard (optional)
  • Salt and pepper
  • Cucumber
  • Tomato
  • Cheese (optional)


  1. Measure 2 tbsp oil and 1 tbsp vinegar into a jar
  2. Notice that they settle into two layers; which is on top?
  3. Pop the lid on and shake – what happens?
  4. Leave it a few minutes and they will seperate again
  5. Add a pinch of salt and pepper and 1 tsp each of honey and mustard, if liked, and shake again
  6. Chop up your veggies, grate in some cheese, drizzle over the salad dressing and serve
  7. If you have a pipette or dropper, try squeezing some drops of coloured water into a glass of oil
  8. Another science trick is to use different liquids to make a density column using a tall, thin glass or tube
    • Start by adding a layer of honey to your container
    • Then carefully squeeze in a layer of washing up liquid
    • Next add a layer of coloured water (dribble it slowly down the side to avoid spoiling the layers)
    • Lastly add a layer of oil
    • Enjoy the beautiful coloured layers but definitely don’t put this one on your salad!

Science in a Sentence

Oil and water-based liquids like vinegar don’t mix (the proper term is immiscible). When you shake, small vinegar droplets are temporarily suspended in the oil – but they will separate out again in time.

Density Details

Oil floats on the top of the water/vinegar because it is less dense. Density is a measurement of how much matter is in a given volume or how much stuff is packed into a given space. Imagine a jar stuffed full of marshmallows – if you take some out and eat them, the contents are less densely packed in – there is less matter in the same space.

Even for liquids that will mix, we can use different densities to create the tower of layers – we love this sugar solution rainbow in a jar. In our tower, the most dense liquid (honey) is heavy and stays sunk at the bottom; the next most dense is the washing up liquid; the water floats on top of that and finally the oil floats on top of the water because it is the least dense.


Kids like this simple cheese salad but you could go gourmet and use feta, onion and olives to make a Greek salad. The honey and mustard dressing also goes well with grilled chicken.

For the unmixables experiment, we used vegetable oil and balsamic vinegar to get contrast but any vinegar will work.

To add drops of coloured liquid to oil, we used a dropper from an empty medicine bottle and a shot glass of oil.

To avoid wasting ingredients for the density column, a small tube is ideal. If you have a science set, it may have a test tube or a measuring cylinder. We repurposed a medicine syringe and sealed the bottom with some sticky tack.

If you are feeling ambitious, you could try making a rainbow coloured density tower from different liquids. Try different syrups, coloured alcohols and flavoured oils to get the range of colours. Grown-ups may find this activity a good use of that green Crème de Menthe or blue Curacao lurking at the back of the spirits cupboard (check out this list of alcohol densities to plan your creations).

Image courtesy of Pexel

Spaghetti and Rainbows

Add a sprinkle of science to the popular rainbow spaghetti activity; the uncooked spaghetti is great for building structures and, after cooking, it can be used to talk about polymers.

Science Ingredients

  • Spaghetti or linguine pasta
  • Marshmallows

Supper Ingredients

  • Spaghetti, linguine or noodles
  • Food colouring
  • Butter or oil
  • Salt and pepper


  1. Connect lengths of uncooked spaghetti by pushing them into the marshmallows
  2. Start by building a square base, then a cube and then try a pyramid – which feels more sturdy?
  3. Who can build the tallest tower?
  4. There is a brilliant activity worksheet from the Science Museum that has lots of ideas and pictures
  5. Cook the pasta according to the instructions, drain and rinse under cold water
  6. Set up small pots or bowls (lidded plastic containers are ideal)
  7. Add a glug of food colouring to each one, then divide the pasta between them
  8. Cover, shake and leave for a few minutes
  9. Cooked spaghetti can be used to illustrate the difference between amorphous and crystalline structure (see below)
  10. To eat your rainbow spaghetti, reheat in the microwave and add oil, butter, salt and pepper to taste

Science in a Sentence

In the spaghetti structures activity, you can see that a wide base and lots of triangles make for a sturdy tower. We love this Science Channel video about triangles (and donuts).

Polymers in a Paragraph

Some polymers have crystalline regions, where the chains line up, and amorphous areas that are messy like a bowl of spaghetti

Polymers are made by chemical reactions that join many small molecules into a long chains. Plastics such as polythene and nylon are polymers. Polymers can be strong, durable and flexible and are important materials. Polymer chains can be arranged in different ways. Polythene has an amorphous (messy) structure like the cooked spaghetti. PET, a type of plastic often used to make bottles, has a semi-crystalline structure where some of the chains are lined up. You can learn more about this difference and the resulting material properties here.


Experiment with the food colouring , mixing different colours to make the whole rainbow. If you only have a few colours, try worms, slime, traffic light pasta or unicorn tails (use red and blue to make pinks and purples).

If you don’t have any marshmallows, use gummy sweets or sticky tape. See who can build the tallest tower with a limited amount of material (Engineers are always thinking about how to optimise resources). Next time you go for a walk, see how many structures you can see that use triangular shapes, there is a nice video from Design Squad here.

Prior to that we built three structures, a cube and a couple of pyramids and were able to confirm that triangles are indeed, to use the technical term, not wobbly.

Vinegar, Volcanoes and Veggies

Fizzing fun with vinegar and baking soda plus a bubbly batter recipe to liven up a few of your five-a-day…

Our space volcano



  • Bicarbonate of soda (baking soda)
  • Vinegar
  • Flour
  • Salt
  • Oil
  • A selection of vegetables such as onions chopped into rings, peppers, courgettes or carrots chopped into thin sticks


  • Bicarbonate of soda (baking soda)
  • Vinegar
  • Foil
  • Egg cup or shot glass
  • Plate
  • Tray
  • Food colour or paint (red, yellow or orange)
  • Washing up liquid



  1. Use foil to make your volcano around the egg cup or shot glass (sit it on a tray to contain the mess)
  2. Add 1 tsp baking soda to the egg cup
  3. Add some red, yellow or orange food colouring, or paint if you have any, plus squirt of washing up liquid
  4. Add a spash of vinegar and watch it erupt


  1. Mix half a cup of flour with 1/2 tsp salt and 1/2 tsp baking soda
  2. Add half a cup of water and 1 tbsp vinegar and mix well
  3. Heat 2 tbsp oil in a frying pan or wok
    1. Dip the vegetables in the batter and fry in batches until golden (take care with the hot oil and lay away from you as you put them in)
  4. Drain on kitchen paper and sprinkle with a little salt
Our onion rings were actually slices and look a lot like crispy prawns!

Science in a Sentence

Vinegar (an acid) reacts with the bicarbonate of soda (a base) to produce the bubbles of a gas called carbon dioxide.


This is our space volcano erupting

Experiment with different containers (thin tubes work well), colours and quantities for the volcano. Can you make a rainbow one? There are some great videos of vinegar volcanos online; check out this one from Ryan’s World.

The batter works well with fish – serve with chips and peas for the perfect Friday night supper. If you find the batter doesn’t stick, try dusting with flour first.

Egg Bounce

Omelette is one of my favourite suppers. Here it’s paired with a fun science experiment that needs just two ingredients: vinegar and an egg. You need to leave it overnight to see the results but it takes seconds to prepare and is worth the wait.

Bounce it gently…oops!

Ingredients for Science

  • Egg
  • Vinegar
  • Jar

Ingredients for Supper

  • Eggs
  • Butter or oil
  • Salt and pepper
  • Milk (optional)
  • Cheese (optional)


  1. Firstly pop your egg into the jar and cover with vinegar
  2. Watch as tiny bubbles form on the shell, pop a lid on and set aside
  3. Now make the omelette: crack three eggs into a bowl, add salt and pepper plus a dash of milk and whisk well
  4. Heat a knob of butter in a non-stick frying pan, then add the whisked eggs and cook on medium for a couple of minutes
  5. Reduce the heat; use a spatula to gently lift the edges and tilt the pan so the runny egg flows into the gaps
  6. Grate some cheese on top and cook on a low heat for a couple of mins before serving
  7. Leave your egg in vinegar for at least 24 hours, ideally 3 days
  8. When it looks translucent (a bit see through) carefully rinse the egg with water and then see if it bounces!

The Science in a Sentence

Egg shell is made of calcium carbonate that reacts with the acidic vinegar releasing bubbles of carbon dioxide, dissolving the hard shell and leaving just the rubbery membrane (skin).

Our bouncy egg


This BBC Good Food omelette recipe gives more detail on how to involve the kids in the cooking plus ideas for fillings. If you want to go gourmet then how about Jamie Oliver’s tomato and basil omelette.

You may notice the egg gets bigger. This is because some of the water in the vinegar has moved through the membrane into the egg.

Bang Goes The Theory has a super explanation of osmosis and also a fun follow-up experiment: you can shrink your egg and dye it with food colouring – that is if it’s not gone splat already like ours did!

You can use any type of vinegar for this but a clear one is best, for example distilled vinegar. If the shell is not coming off easily, put your egg back into the vinegar for another day. When you bounce your egg, start off small and do it in the sink or on a tray to catch the mess if it breaks.

This is what happens if mummy forgets about the eggsperiment…the vinegar evaporated and we grew crystals!

Super Simple Slime

There are thousands of recipes for slime out there but for simplicity you can’t beat cornflour and you can also use it for a yummy cheese pasta for tea.

Fun outside with cornflour gloop

Ingredients for Science

  • Cornflour
  • Water
  • Food colouring (optional)

Ingredients for Supper

  • Cornflour
  • Butter
  • Milk
  • Salt
  • Nutmeg (optional)
  • Pasta shapes
  • Frozen peas (optional)
  • Cheddar cheese (optional)

One of the first things I learned to cook on the hob was white sauce and this recipe uses the method I was taught.


  1. Firstly make the slime…put approx. one cup of cornflour in a bowl
  2. Add half a cup of water and a few drops of food colour
  3. Carefully stir it and add a little more water to make the slime the desired consistency
  4. Whilst that entertains the kids, boil a kettle and cook the pasta according to the pack instruction
  5. Meanwhile, melt 40g of butter in a saucepan then remove from the heat
  6. With a wooden spoon, stir in around 25g cornflour and cook, stirring, for one minute
  7. Off the heat, gradually add 450mL milk, stirring to mix well (you can also use a whisk)
  8. Back on the heat, stirring all the time, cook until you feel it thicken and it coats the back of the spoon
  9. Add salt, pepper, nutmeg and grated cheese to taste and set aside
  10. Just before the pasta cooking time is up, add a handful of peas to the pasta water
  11. Drain the pasta and peas, add the white sauce and serve topped with more cheese if liked

Science in a Sentence

The mixture flows like a liquid but when you squeeze it feels like a solid; this is called a non-Newtonian fluid. You can find out more here.


If sauce stirring seems like too much hard work, there is a microwave white sauce recipe here on the SimplyBeingMum blog.

You can use leftover white sauce to make all sorts of dishes including lasagne, pasta/potato/vegetable bakes and fish dish.

You can also add food colour to the white sauce to make slime pasta 🙂

If you have the stuff, there are some great recipes for different types of slime on Science Sparks.

Fizzy Fruit

A simple experiment with raisins and fizzy drink, paired with a healthy dinner for the whole family.

Ingredients for Science

  • Raisins
  • Fizzy drink (lemonade, tonic water or similar)
  • Glass or clear plastic cup
  • Tweezers

Ingredients for Supper

  • Raisins
  • Cous cous
  • Stock cube
  • Onion
  • Oil or butter
  • Mild curry powder
  • Frozen peas
  • Tinned tomatoes


  1. Chop the onion and fry gently until soft
  2. Add 1tsp curry powder (if liked) and fry for a minute more
  3. Add a tin of tomatoes and a few handfuls of raisins
  4. Simmer the sauce gently whilst you do some science…
  5. Use the tweezers to drop a few raisins into a glass of lemonade and watch what happens
  6. Back to supper…add a handful of frozen peas to the pan
  7. Boil the kettle and dissolve the stock cube in 350mL hot water
  8. Add 200g cous cous to the jug
  9. Cover and leave for five mins
  10. Fluff up the cous cous with a fork and add to the sauce.
  11. Serve with a glass of lemonade (or G&T for grown-ups!)

Science in a Sentence

Bubbles of a gas called carbon dioxide, that make the drink ‘fizzy’, cling to the raisins which makes them float to the surface; as the bubbles pop, the raisin sinks again. The Naked Scientists have a nice explanation here if you want to know more.

Super simple fizzy fruit
Look at those bubbles!
Dancing raisins


A clear fizzy drink works best, I have not tried Prosecco yet! For the fruit, you could also use sultanas or cranberries. The supper serves 4 although if grown ups are eating too, you might want to accompany with some bread or you could add in some meat or fish to increase the portion size. Instructions for cooking cous cous vary; the quantities above work well for the one I buy.

Supper sorted

Cabbage Chemistry

Royal Institution At Home Science

As the nights draw in, red cabbage with sausages makes for a comforting supper. Whilst it’s cooking, learn about acids and bases by making a pH Indicator just like this one from the Royal Institution.


Red cabbageRed cabbage
Onion (red or white)Jug of hot water
Salt and pepperThree glasses or clear plastic cups
SugarBicarbonate of soda


  1. Pre-heat the oven to 190 degrees C (or 170 fan), put the sausages in an oven tray with a little oil and cook for 20 – 25 minutes or according to the pack instructions.
  2. Cook the cabbage
    • Shred about half a cabbage and chop one onion
    • Put in a microwavable dish with some salt and pepper
    • Add 2 tablespoons each of sugar, vinegar and water
    • Cover and microwave for 5 mins
    • Check, stir, re-cover and cook for a further 5 mins
  3. Cabbage chemistry
    • Chop up around a quarter of cabbage
    • Add to a jug of hot water, stir and wait a few minutes
    • Pour some of the purple liquid into each glass
    • To one glass, add some vinegar – see the colour change
    • To another glass, add some bicarbonate of soda
    • Compare these colours to the original
  4. Serve supper
    • Check the sausages are piping hot in the middle
    • Serve with the cabbage and some instant gravy (I use gravy granules mixed with hot water from the kettle)


What’s going on? The science in a sentence…
A chemical in the cabbage, called anthocyanin, changes colour depending on whether it’s mixed with an acid (like vinegar) or a base (like bicarbonate of soda).

Other ideas for supper…
If you fancy something even easier, this cabbage recipe goes well with leftover turkey, shop-bought breaded chicken or oven-baked chicken drumsticks. If you don’t eat meat then try it with some grilled halloumi cheese or vegetarian/vegan sausages. If you want to go gourmet then add some apple and spices and slow-cook the cabbage as in this recipe from BBC Good Food.

And finally….
If you want to experiment further, try using your cabbage indicator to test other things to find out if they are acid or base. You can try lemon juice, egg, washing-up liquid, cola, orange juice, coffee, toothpaste, soap and apple juice and make a rainbow like this school science club did. You can freeze your indicator liquid into ice cubes as shown here by The Science Kiddo. You can also see if you can make the cabbage indicator go back to it’s original colour (neutral pH).

Pizzas and Lava Cups

Pizza is really easy to make with just a few ingredients: flour, salt and oil. Top with tomato puree and add some cheese for a super-simple supper. Whilst it’s cooking, use some oil and salt to make lava flows just like in this video.

Make lava-like flows in the cup using oil, salt and food colouring


Pizza:Lava Cups
FlourFood colouring
Tomato pureeA glass or clear plastic cup
Toppings e.g. cheeseWater


  1. Boil the kettle and pre-heat the oven to 220°C (the pizzas can be finished in the oven…or a pan in which case skip this bit)
  2. Make the pizza bases
    • Measure 400g plain flour into a bowl
    • Add a pinch of salt
    • Make a well in the middle and add 1tbsp oil and 240ml warm water
    • Mix until the dough comes together then tip out onto a large sheet of baking paper
    • Divide into four balls and roll them out as thinly as you can
  3. Cook the base
    • Heat a little oil in a frying pan over a medium-high heat
    • When the oil is hot (has a slight shimmer and flows freely when you tilt the pan), carefully put the pizza in, laying away from you into the pan
    • Cook for a few minutes until the underside starts to brown then turn off the heat
    • Flip the base over so the cooked side is facing up and remove to the baking paper
    • Repeat for the other pizzas
  4. Add the toppings
    • Spread with tomato puree (or I have been known to use ketchup)
    • Sprinkle with grated cheese (cheddar works fine)
    • Top with any other favourite toppings like ham, sweetcorn or peppers
  5. Cook the pizzas
    • Place the pizzas directly on the oven shelf
    • Cook for 5-8 mins at 220°C
    • You can also cook pizza in the pan (heat a little oil on a medium heat, add the pizza and cook until the cheese has melted and the underside is starting to brown; to help the cheese melt, cover with a lid for a few minutes).
    • Whilst the pizza cooks, do a little science….
  6. Lava cups (adapted from the brilliant Science Bob)
    • Fill a glass or clear, plastic cup with water to around 3/4 full
    • Add a few drops of food colouring
    • Pour some oil into the cup
    • Sprinkle some salt on top of the oil


What’s going on? The science in a sentence…
The salt sinks down taking some of the oil with it; the salt dissolves in the water so the oil floats back up to the surface.

Other ideas for supper…
If you fancy something even easier then supermarkets sell dough mixes (and if all else fails order a takeaway and do the science whilst you wait for it).

The recipe here is quick and easy but pizza is traditionally made with “00” flour and yeast so if you want to go gourmet then check out this more authentic recipe here.

There is also a great one for kids (pizzas with veggie faces) here. Lastly check out this quick and easy homemade pizza sauce.

If you have time to melt some butter then the dough recipe from Recipetineats is amazing. I make a batch every week and use it for wraps, pan pizzas and flatbreads.

And finally….
If you enjoyed the lava in a cup and have any fizzy vitamins or Alka-Seltzer® tablets and a glass bottle or jar, then you can make your own lava lamp using similar principles. I love the themed ones on Science Sparks – there is even a Minion one.

Making some yellow lava cups outside