Magnets at Science Club

Magnets and Electricity
image

Introduction

Has anyone heard of magnetic poles? A magnet has two poles: North and South. If you put two South poles near each other, they will repel each other; if you put two North poles together they will repel each other; if you put a North pole near a South pole, they will attract each other.

Give out coloured magnets and let the children try this out for themselves.

How strong are these magnets? Magnets exert their force over some distance, but what is the farthest distance we can put our magnets and still have them affect each other?

Hand out tape measures and encourage the children to experiment.

 

Individual Task

Give out Magnet Experiment sheets. The children should predict which items will be magnetic, then test their predictions and see if they were right.

Magnets

Did you predict which things would be magnetic? Can you suggest some rules about what substances are magnetic and what substances aren’t?

Some metals are magnetic, more specifically iron and steel (an alloy of iron and carbon) are magnetic (also samarium and neodymium). In fact, the name for things that are attracted to magnets and are magnetized by touching magnets is Ferromagnetic, from Ferro meaning iron.

(If a material lines itself up with a magnetic field it is dangled in, it’s Paramagnetic.)

Paperclips are magnetic, so we’re going to use them to make a magnetic fishing game. Draw some fish and cut them out, then attach a paperclip to each one. Tie your ring magnet to a rope and a stick to make a fishing rod. See how many fish you can ‘catch’ in a minute, or time how long it takes you to catch them all.

 

Break for drink and snack

 

Gather Together

Does anyone know how to make a magnet?

Most of the electrons in an atom exist in pairs that spin in opposite directions, so the magnetic effect of one electron in a pair cancels out the effect of its partner. But if an atom has some unpaired electrons (iron atoms have four), these produce net magnetic fields that line up with one another and turn the whole atom into a mini magnet. When you put a paramagnetic material such as iron in a magnetic field, the electrons change their motion to produce a magnetic field that lines up with the field outside.

To make a magnet, we need to line up these unpaired electrons, and the magnetic fields throughout our object, to create one unified magnetic field.

There are three ways to do this.

The first way is with electricity. You may remember from our generators session that there is a connection between magnets, movement and electricity, if you have two of them, you can make the third. We used this theory to make electricity by spinning magnets set around a coil of wire. If I put electricity through a coil of wire around something iron, I can make an electromagnet.

Demonstrate making an electromagnet.

There are two other ways of making a magnet, and we’re going to test them both and see which is best.

First we’re going to try touching a magnet to a needle to magnetise the needle. We can check that our needles are magnetised using paperclips.

Then, we can use our magnetic needles to make simple compasses. If we put our needles on a bottle cap and float them in water, they will align themselves up with the Earth’s magnetic field and point North.

Let all the children have a go at making simple compasses.

There is one final way of making magnets. If we can line our metal up with the Earth’s magnetic field (which we can use our compasses to help us with!), and give it an encouraging tap – or twenty – then we should be able to magnetise our metal in that fashion.

Let all the children have a go and discuss the easiest method for magnetising metal.

Advertisements

Science Club – Cams

Cams and pulleys
image

Arrival Craft: make wheels for tiny cars using plasticine; children should make one car with round wheels and one with different shaped wheels and see the ways they roll.
image

 

Demonstration: what was the difference between the round wheels and the different shaped wheels? Round wheels roll more smoothly, but different shaped wheels bump a lot. We can use that ‘bumping’ action to push things up. Show the children a ready made cam toy.

 

Individual Task: make a moving toy using the techcard kit, smaller children will need a lot of grownup help.
We’ve used tech card before, and I really love it! It’s so easy to use and the children can make some fantastic models very quickly.
 

Gather together: Cams are one of the ways that engineers can turn one type of movement – going round and round – into another – going up and down.

Break for drink and snack, read Did I Ever Tell You how Lucky You Are?

 

Final Activity:

    We finished off the session by making very simple rocking animals. We folded paper plates in half to make the rocking base, then decorated with pens to make animals. I made a rabbit to show the children, with a little cotton wool tail, but they all had their own ideas!

Bones at Science Club

Bones

humanskeleton

  • Guess the animal quiz. Lay out animal Xrays, give each child a sheet to write their guesses.

I got a couple Xray sets for Christmas, which I wanted to share with the children:

This is the animal one.
image

  • Make model bones. Take wool – one red piece, one blue (artery & vein) – lay the wool on top of a piece of tissue paper (bone marrow), wrap the tissue around, wrap this tube in a sponge (soft part is spongy – cancellous – bone, scratchy bit is compact bone), put the whole thing inside a toilet roll tube (periosteum).
  • I found this craft on another fantastic home educator’s blog here.

  • Sort the animals. Divide the children into two groups & give each group half of the pictures. Encourage them to examine the Xrays & compare the animals. See if the children can identify the groups that the animals belong to. Ask if the children know what all the animals have in common (a spine!)
  • Make model spines. Cut egg boxes into sections (vertebrae), cut some spongy discs (intervertebral discs), punch holes through them all, thread egg box sections alternated with discs on a pipecleaner (spinal cord).
  • Another borrowed craft! I was inspired by this blog.

  • Break for drink & snack – icing our own gingerbread men.
  • image

  • Lay out the human Xrays to make a skeleton.
  • image

This is the set of human Xrays I got for Christmas. If you don’t have these sets, you could print Xray pictures of the internet.

  • Use pre-printed slips to label the bones.
  • Hand out Human Body Ratio Experiment sheets and tape measures. Bone relationship is represented by the following formulas:

P represents the person’s height. The last letter of each formula stands for the known length of the bone (femur, tibia, humerus, or radius) through measurement.

Femur:

P = 61.412 + 2.31F

Tibia:

P = 72.572 + 2.533T

Humerus:

P = 64.977 + 3.144H

Radius:

P = 73.502 + 3.876R

Children should measure their height, the length of their femur, tibia, humerus and radius. Then they should work out whether the formulae are correct in their case.

Here’s the sheet I made to give the children: Bones

In theory, this will be more accurate for the adults than the children, because children are still growing. However, our sample size is not very big!

Growing Up

Eldest and Middly are quite close in age. One if the ways we’ve tried to help Eldest feel confident in his role as the oldest brother has been The List.
It’s a slightly bizarre list of privileges and special things that come with reaching certain ages. We tried to choose things that required little in the way of maturity since you can’t always expect maturity to come with age.
After Baby was born, we went back and  added things to the lower ages, so we had one for every birthday.
1) Choose a meal on special days (since we always have a meal plan we regularly have weeks when the children pick meals to have, when Baby reached one, we figured he was old enough to have a pick in there too).
2) Pour juice.
3) Spread jam.
4) Choose your own clothes after school and at weekends.
5) Pause the TV.
6) Sit – on the correct car seat – in the front of the car sometimes.
7) Get an electric toothbrush.
8) Light candles under supervision.
9) Turn on the computer – though Mum & Dad might ask you to turn it off again if you chose a bad time.
10) Get an approved pet.
11) Get a mobile phone.
12) Get a front door key.
13) Get a laptop or contemporary equivalent.
14) Choose your own bedtime.
15) You may use your computer alone in your room (currently, all electronic devices remain downstairs at all times).
16) You can choose your own clothes to buy.
17) Mum and Dad will fund a couple of days away for you and a friend – details to be agreed.
18) You can come and go as you please, but Mum and Dad don’t promise to fund all excursions.

The boys love the list. Even though not everything on it is exciting in itself, the fact that it’s only available at a particular age makes it special. It remains to be seen whether it’s as popular when they get older.