Grow a Crystal

You will need

  • Short length of wool or string
  • Warm water
  • 2 Paperclips
  • 1 Plate
  • 1 Spoon
  • 2 Glass jars
  • Washing soda

What to do

  1. Fill both jars with warm water. (From the tap is fine.)
  2. Add washing soda to both jars and stir until no more washing soda dissolves.
  3. Attach a paperclip to each end of the string or wool.
  4. Place the ends of the string in the jars, so the string hangs between the jars.
  5. Place a plate between the jars to catch the drips of the solution flowing along the string or wool.
  6. Leave the jars for one to two weeks in a safe place and observe what happens.


The washing soda solution slowly soaks the string or wool and flows along it. As the solution drips off some washing soda is deposited slowly forming a crystal.

Water flowing underground dissolves minerals when it seeps through rocks. The minerals are deposited when the water drips of a cave roof. A crystal is formed that hangs off the cave rood which we call “stalactite”. When the water drips to the floor it deposits minerals there forming a crystal growing up from the ground which we call “stalagmite”.

In your experiment a stalactite grows hanging from the string or wool.

You can watch a video of this experiment:

Combustion of Christmas Nuts

You will need

  • 1 Sharp knife
  • Matches
  • Heat proof surface, for example a pan or a ceramic plate
  • 1 Potato
  • 1 Peanut
  • 1 Almond
  • 1 Walnut
  • If you are allergic to nuts you can use sunflower and pumpkin seeds instead.

What to do

  1. Cut a potato into a long cylinder or a tall rectangular cube.
  2. Carefully cut a long thin strip from the peanut, almond and walnut.
  3. Stick 1 peanut strip into the top of the potato. The potato will hold the peanut while it is burning.
  4. Light the peanut strip with a match. Let it burn until it goes out.
  5. Repeat steps 3 and 4 with one almond and one walnut strip.
  6. Which nut burns longest? Which nut is easiest to light?


Nuts contain oil that can be lit to create a fire. The oil and the oxygen from the air undergo a chemical change during the fire turning them into carbon dioxide gas and steam. This type of reaction producing a fire is called “combustion”.

The nut that lights fastest and burns longest contains most oil. Which nut contained most oil?

You can watch a video of the experiment here:

Home Experiment: Halloween Slime

You will need

  • Bowl
  • Measuring cup
  • Spoon
  • 1 cup of cornflour
  • ½ cup of water
  • Food colouring (you can choose which colour)
  • Plastic container with lid for storage

What to do

  1. Measure out 1 cup of cornflour and place it in a bowl.
  2. Measure out ½ cup of water.
  3. Slowly add some of the water to the cornflour and mix with your hands.
  4. Then add some more water and keep mixing with your hands.
  5. Continue adding water and mixing until your slime has the right consistency.
  6. If gets is too runny you can add some more cornflour.
  7. Add about 10 drops of food colouring until your slime and mix it.
  8. You can store your slime in a plastic container with a lid. Your slime might still dry out a bit over time. If this happens you can just add some more water.


Mixing cornflour and water gives you a slime that behaves very peculiar. If you touch it very lightly it feels liquid like water. If you hit it very hard and fast it feels solid like a rubber ball. The slime reacts differently depending on the force that acts on it. The bigger the force, the harder the slime. The smaller the force, the more liquid the slime behaves. These kind of liquids are called “non-Newtonian”.

You can watch the experiment as a video here:

Air Pressure Experiments

You will need:

1st experiment:

  • Glass bottle
  • Balloon

2nd experiment:

  • One piece of card board
  • Glass
  • Water

What to do:

1st experiment:

  1. Stretch the opening of the balloon over the rim of the bottle’s mouth. Make sure that the body of the balloon is inside the bottle.
  2. Try to blow up the balloon.
  3. The air in the bottle has nowhere to go and pushes on the balloon. This increases the pressure in the bottle when you try to blow up the balloon and you will not be able to blow it up.

2nd experiment:

  1. Pour water into the glass until it reaches the rim of the glass.
  2. Place the piece of card board on the glass. Hold it down so the card board covers the rim all the way around.
  3. Still holding the card board, move above a sink.
  4. Turn the glass upside down while still holding the card board. Then let go of the card board.
  5. Air pressure forces the card upwards, against the glass. The pressure is strong enough to stop the weight of the water pushing the card away.

You can watch a video for this experiment here:

Home Experiment: Fire Extinguisher

You will need

  • Tea light
  • Tea spoon
  • Small bowl
  • Vinegar
  • Baking soda
  • Match to light the candle

What to do

  1. Place the tea light in the middle of the bowl.
  2. Arrange the baking soda in the bowl around the tea light using the tea spoon.
  3.  Light the tea light.
  4. Slowly add vinegar to the baking soda around the tea light. Be careful not to put the vinegar directly into the flame.
  5. Observe what happens to the candle.


When vinegar reacts with baking soda, the gas carbon dioxide is formed. Carbon dioxide is heavier than air and stays in the bowl. Carbon dioxide gas replaces the air with the oxygen needed for the tea light’s flame in the bowl. Finally, the non-flammable carbon dioxide gas smothers the flame.

You can watch this experiment as a video here:

Vinegar and Baking Soda Bomb


Vinegar is an acid and reacts with baking soda to form salt, water and carbon dioxide gas. The extremely fast formation of carbon dioxide gas will cause your zipper back bomb to explode.

You will need

  • Plastic zipper bag
  • Vinegar (any kind will do, but you will need quite a lot of it)
  • Baking soda
  • Cup, glass or mug
  • Table spoon

What to do

  1. Go outside to do this experiment.
  2. Check your zipper bag to make sure that it does NOT have any holes or rips before the experiment.
  3. Fill your glass or mug completely with vinegar
  4. Pour the vinegar from your glass or mug into the plastic zipper bag.
  5. Place the zipper bag on the ground.
  6. Add one heaped table spoon of baking soda and quickly close the bag.
  7. Quickly step away from the zipper bag and watch what happens.

You can watch this experiment here:

Best of Current Science Documentaries

From dinosaurs to the Solar System, here is a guide to the best Science documentaries on Netflix and BBC iPlayer right now.


Science and Technology

  • Revolutions: From the car to the robot, this series takes you through humanity’s greatest inventions and their history.
  • Apollo 11: This documentary explores the adventure of the first moon landing with recently rediscovered original footage.
  • Mission Control: From flight doctor to IT, this film highlights the importance of the jobs on the ground during the moon landings.
  • The Universe: Explore the secrets of the universe in this series which also teaches you about the latest discoveries.

Nature and Natural History

  • Walking with Dinosaurs: Dive into the world of dinosaurs as they come to life in this series.
  • Night on Earth: This nature series’ new technology lifts the darkness and reveals the lives of animals at night.
  • The Tigers of Scotland: This film tells you about the life of the endangered Scottish wild cats.
  • A Plastic Ocean: This documentary investigates the environmental impacts of plastic pollution on animals living in the ocean.

BBC iPlayer

Science and Technology

  • Chemistry – A Volatile History: This series shows the breakthroughs that made it possible to harness elements and compounds.
  • Shock and Awe: This series takes you through the history of electricity and the latest discoveries in the field of electricity and magnetism.
  • The Planets: Professor Brian Cox takes you to the origins of our Solar System and its planets, from Mercury to Neptune and even Pluto.

Nature and Environment

  • War on Plastic: This documentary explains how you can reduce your use of plastics to help the environment.
  • Seven Worlds, One Planet: This series takes you to each continent and shows you how its animals live.
  • Forces of Nature: Professor Brian Cox explains how natural events create Earth’s beauty.
  • Dynasties: From tigers to penguins, this series follows endangered species that fight for their survival.

M&M Diffusion Experiment


Diffusion is the movement of particles from a place of high concentration to a place of low concentration. We can also say that particles move from where there are lots of particles to where there are less particles.

In this experiment we are going to look at the diffusion of colour particles. You will observe the colour moving away from the sweets where lots of colour particles are found to places with less colour particles in the middle of the plate.

You will need

  • M&Ms or Smarties
  • Plate
  • Water

What to do

  1. Once you start this experiment, you cannot move it. So, make sure you choose a good spot to start.
  2. Pour the bag of M&Ms or Smarties onto your plate.
  3. Remove the sweets that landed in the middle of your plate.
  4. Place the remaining sweets in a circle around the outside of your plate.
  5. Remove any remaining M&Ms or Smarties that do not fit in the circle.
  6. Slowly add water to your plate. It needs to reach the M&Ms, but they should not float. From now on you cannot move the experiment.
  7. Observe what happens to the colour of the sweets.

You can also watch this experiment on YouTube:

Reading Exercise: Titration

Titration experiments can be used to produce pure salts by reacting acids and alkalis in a very controlled way. A neutralization reaction takes place where acid and alkali react to form the neutral products salt and water.

In a titration, the acid is added to a fixed volume of alkali, for example sodium hydroxide, in a conical flask. A burette is used to slowly drip the acid into the conical flask. The burette is a tall apparatus with a tap at the bottom that controls the flow of the acid (see image above).

A few drops of indicator are added to the alkali, so you can follow the reaction. The end-point is when the indicator changes colour. A single indicator like phenolphthalein is used because it shows only one very obvious colour change and gives you a sharp end-point. Phenolphthalein will change from pink to colorless at the end-point.

To obtain the pure salt, the water needs to be evaporated from the solution after the end of the titration by heating.

In industry, titration is used in many fields not only to produce pure salts, but also to test the amount of acids or alkalis in materials. For example, titration is very common to determine the amount of acids and alkalis in foods like chocolate. The method is also applied by construction companies to investigate the quality of building materials.


  1. What is produced by a titration experiment?
  2. Which reaction takes place generally during a titration experiment?
  3. Name the tall apparatus used to add the acid to the conical flask with the alkali.
  4. Which indicator can be used to identify the end-point of a titration experiment.
  5. Why is universal indicator not used to identify the end-point?
  6. What are the colours of phenolphthalein in an acid and in an alkali?
  7. What needs to be done after the titration to obtain the pure salt?
  8. Name two uses of titration experiments in industry.

Rainbow in a Glass


Density tells you how heavy a certain volume of a substance is. It decides which materials can float on water and which sink. For example, a rock will sink because its density is higher that the density of water. However, wood floats because its density is lower than that of water.

The same is true for liquids. Liquids with high densities sink, while liquids with lower densities float. We are going to use this to make a rainbow in a glass. Chocolate sauce has a highest density of the four liquids and will stay at the bottom. However, water has the lowest density and will, therefore, float on top.

You will need

  • 1 Glass
  • 1 Spoon
  • Chocolate sauce
  • Honey
  • Washing up liquid
  • Water
  • Red food colouring

What to do

  1. Start by pouring chocolate sauce into your glass until it is one quarter full.
  2. Use the spoon to carefully add the honey until your glass is half full. Do NOT stir!
  3. Now add the washing up liquid slowly and until your glass is three quarters full.
  4. In a separate glass mix water with red food colouring.
  5. Carefully add the water dropwise until your glass is full. Do NOT stir!

You can watch this experiment as a YouTube video: