Fill both jars with warm water. (From the tap is fine.)
Add washing soda to both jars and stir until no more washing soda dissolves.
Attach a paperclip to each end of the string or wool.
Place the ends of the string in the jars, so the string hangs between the jars.
Place a plate between the jars to catch the drips of the solution flowing along the string or wool.
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.
Heat proof surface, for example a pan or a ceramic plate
If you are allergic to nuts you can use sunflower and pumpkin seeds instead.
What to do
Cut a potato into a long cylinder or a tall rectangular cube.
Carefully cut a long thin strip from the peanut, almond and walnut.
Stick 1 peanut strip into the top of the potato. The potato will hold the peanut while it is burning.
Light the peanut strip with a match. Let it burn until it goes out.
Repeat steps 3 and 4 with one almond and one walnut strip.
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?
Measure out 1 cup of cornflour and place it in a bowl.
Measure out ½ cup of water.
Slowly add some of the water to the cornflour and mix with your hands.
Then add some more water and keep mixing with your hands.
Continue adding water and mixing until your slime has the right consistency.
If gets is too runny you can add some more cornflour.
Add about 10 drops of food colouring until your slime and mix it.
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”.
Shine the torch through the beaker of water. It looks white like the sun when it is high up in the sky.
Pour a little milk into the water in the beaker.
Stir the water gently, so that it all goes slightly white.
Shine the torch through the water again. It will look different.
Again, add a bit more milk to your glass and stir again.
Shine the torch through the water again and observe what the light looks like now.
You can repeat the steps of adding milk, stirring and shining a light through several times.
When the sun is low in the sky, in the morning and the evening, its light passes through more air than at other times of day. Tiny particles of air stop much of the sun’s light. Only orange and red light gets through. The same happens when you shine your light through the milk-water mixture. Tiny particles from the milk stop most of the light. Only some colours pass through. Which colours did you see?
Place the open bottle in the freezer for 10 minutes.
Remove the bottle from the freezer and moisten the rim of the mouth with some water.
Cover the rim of the coin with some water, so that nor air can pass through.
Place your hands around the bottle.
Observe what happens.
You will be able to observe the coin moving as if a ghost was in the bottle. The cold air in the bottle is warmed by your hands and expands. The coin and water prevent the air from escaping the bottle. However, if the pressure gets high enough, the coin acts like a valve and moves releasing the warm air from the bottle.
You can watch the video for this experiment on YouTube:
Arrange the baking soda in the bowl around the tea light using the tea spoon.
Light the tea light.
Slowly add vinegar to the baking soda around the tea light. Be careful not to put the vinegar directly into the flame.
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.
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
What to do
Once you start this experiment, you cannot move it. So, make sure you choose a good spot to start.
Pour the bag of M&Ms or Smarties onto your plate.
Remove the sweets that landed in the middle of your plate.
Place the remaining sweets in a circle around the outside of your plate.
Remove any remaining M&Ms or Smarties that do not fit in the circle.
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.
Catalysts are substances that speed up chemical reactions. However, they do not directly take part in the reaction and are not used up themselves.
Cars contain catalysts in catalytic converters that split toxic substances released by the car’s engine into less harmful ones.
The gas bubbles inside coke are the result of a chemical reaction where carbonic acid decomposes to water and carbon dioxide gas. The bubbles you feel when drinking coke are carbon dioxide. The word equation for this reaction is:
Carbonic acid → Water + Carbon dioxide
Carbonic acid is the reactant. Water and carbon dioxide are the products.
Mentos can act as a catalyst and increase the speed of carbon dioxide production. This causes the foaming you can see when adding Mentos to coke. The scientific word for bubbles, fizzing or foaming is effervescence.
You will need:
1 bottle with coke or diet coke (Normal coke and diet coke both work, but diet coke is less sticky and easier to clean up afterwards.)
1 pack of Mentos
What to do:
Go outside to do this experiment.
Put the coke bottle on the floor and remove the lid.
Put about 5 pieces of Mentos inside at the same time.
Step back and watch.
You should see a lot of foaming due to the increased carbon dioxide production.
What is meant by a “catalyst”?
What is the catalyst in this reaction?
Is the Mentos used up in this reaction or not? Why?
What is meant by the “reactant” in a reaction? What is the reactant in this reaction?
What is meant by the “product” in a reaction? What are the products in this reaction?