## How to make electricity: Falling Magnet Experiment!25/09/2019

Can we make a magnet fall in slow-motion? Is copper magnetic? How do we make electricity?

All great questions…Let’s find out!

#### You will need:

• A straight copper pipe (at least 100cm in length)
• Small neodymium magnets *adult supervision required*
• A stopwatch/egg timer *optional*

A length of copper pipe and a neodymium magnet.

#### Method:

• Try holding a magnet against the outside of the copper pipe and let go – it doesn’t stick! That’s because copper is not magnetic.
• Now try holding the copper pipe upright and drop the magnet through the pipe – the magnet should take several seconds to appear at the bottom of the pipe.
• You can try timing how long the magnet takes to fall to the floor inside the pipe and outside the pipe with a stopwatch or egg timer.
• Longer or thicker copper pipe will slow the magnet down even more.

#### The science bit:

• Inside everything, there are electrons. If these electrons are facing or moving in a certain way they produce electricity.
• Copper is not usually magnetic, so when a magnet is brought close to the copper pipe nothing happens. But when a magnet is in motion (when it’s moving) inside the copper pipe the electrons in the magnet pull on the electrons in the copper pipe which creates a small bit of electricity! This electrical energy doesn’t come from nowhere – the magnet has to convert some of its momentum (kinetic/movement energy) into electrical energy, and that’s why the magnet slows down while it’s falling through the copper pipe.
• We make most of our electricity using large magnets and copper!

## Mind-Boggling Bubbles: 3-Dimensional Bubble Wand!04/06/2019

The special tool you use to make bubbles is called a “Bubble Wand”. Bubble Wands come in all shapes and sizes but no matter what 2-dimensional shape you make your wand, the bubbles will come out round like a ball (sphere). But what if we make a 3-dimensional bubble wand? Can we make a bubble that is a different shape? Time to find out!

#### You will need:

• A washing up bowl
• Measuring jug
• Washing up liquid (any brand)
• At least 4 metres of medium thickness aluminium wire (can be found in most craft or DIY stores – Hobbycraft, Wilkos etc.)
• Pliers for cutting/bending the wire (adult supervision may be required)
• Glycerin for bubble mixture (optional)

#### Method – Bubble Mixture:

• Fill your washing up bowl with water (most washing up bowls hold around 5 litres of liquid)
• For every 1 litre of water, add 70ml of washing up liquid.
• Mix gently, try not to let lots of bubbles form on the surface of the mixture.
• Optional – Once the washing up liquid has been mixed in, add 15ml of Glycerin for every litre of water (Results are best if the Glycerin-bubble mixture is left overnight)

#### Method – Bubble Wands:

• Get your grown up to cut the wire into the appropriate length using the pliers
• Bend one piece of wire into a 3-dimensional triangle (tetrahedron)
• Bend the other piece of wire into a 3-dimensional square (cube)
• Fun Science Tip! – Make sure your 3-dimensional bubble wands are small enough to be fully submerged in the bubble mix.
• If you have leftover wire, try making other 2-dimensional or 3-dimensional bubbles wands.

#### The Experiment:

• Submerge your tetrahedron bubble wand into the bubble mix and then take it out. You will see the bubble mixture meets in the centre of the wand, creating a strange geometric shape!

• Now try with your cube bubble wand… The bubble mixture meets in the centre of the wand just like before, but this time there is a flat square in the middle!

• You can try blowing a bubble into the centre of your cube bubble wand to create a smaller cube!

#### The Science Bit:

The bubble mixture wants to pull together tight and get as small as possible, scientists call this Surface Tension. When you blow a bubble, the bubble mixture pulls together around the air inside the bubble and the smallest shape it can pull itself into is a sphere. That’s why all 2-dimensional bubble wands make bubbles that are spheres.

When we use a 3-dimensional bubble wand and don’t let any air inside the bubble, the surface tension of the bubble mixture pulls tight into a different shape because a sphere is not the smallest shape possible.