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.
- 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!
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.
- 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.