Experiments with Magnets

by Elisabeth Nawroth

With a small group of five children, I carried out three consecutive activities on the theme of „The Magnet“, each of which lasted about an hour. In order to be able to respond flexibly to the needs and ideas of the children, I did not set a fixed time frame for the individual project units.

The participating children were (names changed):

Tanja , 5 years old,
Leonie, 4 years old,
Sigrun, 5 years old,
Laura, 4 years old,
Janek, 4 years old.

I got to know them all through my advisory work within the DGhK. (This is a german society for the promotion of highly gifted children). They only knew each other to some extent, so a getting-to-know-you phase had to be planned at the beginning of the project.

The children are not tested yet, they attend different kindergartens.

Preliminary information:

Magnetic is the name given to those metals that attract iron, cobalt and nickel, but not other substances such as wood, brass, lead, ceramics, etc. The natural magnetic ironstones are only very weakly magnetic. The artificial magnets used today are made of steel or certain alloys.

… in brief …

The author offers five still very young children to do experiments with magnets. The children are very interested and persistent. They easily gain insights that are sometimes only taught in secondary schools.

The points of strongest attraction of a magnet are called poles. If you hang a bar magnet in the middle on a thread, one of its ends will point to the north. The pole facing north is called the north pole, the other the south pole.

The north pole of one magnet attracts the south pole of another magnet. However, two north poles repel each other, because unequal poles attract each other and equal poles repel each other.

The magnetic lines of force run from one pole of a magnet to the other. If you attach a freely movable pole of the same name to one pole, it will be repelled along a line of force by one pole and at the same time attracted by the other pole. The totality of these lines of force is called the magnetic field.

Various magnets and compasses are available in well-stocked toy shops, for example at Wehrfritz.

Iron filings are available in locksmith’s shops.

Unit 1: What materials does a magnet attract?

Objective:
The children realise that the magnet has the power to attract some objects.

Procedure:
For 1O minutes we played getting-to-know-you games, then I brought a fishing game with magnetic and non-magnetic fish to the table.The game was familiar to the children, they now had a lot of fun fishing for things that don’t actually belong in the fishing game (paper clips, nails, screws, crown caps).

After the fishing game, the children wanted to try out the effect of the magnet on other objects in the room. They tested with their magnets whether the things could be attracted or not.

The test objects were wood, corks, crown caps, scissors, money, sponge, paper clips, keys, screws, paper notebooks, nails, wool, stones, needles, a Pixi book and a soft toy.

They distributed the tested objects on two prepared posters with the symbols for „magnetic“ and „non-magnetic“ .

The assignment of the real objects to the symbols went without difficulty. Janek had sorted the nails to „non-magnetic“, but this was then immediately noticed and corrected by the girls.

In the conversation it became clear that the children were already familiar with magnets; however, they could not name any examples from the household.

Unit 2: A magnet works through objects

Objective:
The children realise that the magnet does not always have to be in direct contact with the object to be attracted.

When the mothers brought their children to the second project unit, they reported that their children had already been waiting impatiently for the next meeting. Even Janek, whom the mother had warned me that he wouldn’t do anything if he didn’t feel like it, was happy to come back and also participated well in the second lesson.

The topic of the second lesson was introduced by the following demonstration: On the front side of a cardboard (approx. DIN A 4 size) a paper clip moves, which is „controlled“ by a magnet on the back side of the cardboard. The magnet is not visible to the children, but Laura immediately sees through this „magic trick“ and explains the connection to the other children.

We then carried out the first experiment.

EXPERIMENT 1:

Material:
a paper clip, a ruler, several magnets.

Experiment set-up:
A paper clip lies next to the long side of a ruler (in the zero area); with a magnet, the children approach from the end of the ruler and can thus read off the distance at which the magnet acts on the paper clip.

The children actually realise that a magnet can only attract an object at a certain proximity. The experiment is repeated with several different magnets. All five children understand that the magnets have different strengths.

EXPERIMENT 2:

Material:
several (school) paper notebooks / thicker and thinner cork discs / thicker and thinner wooden discs, a paper clip, a magnet.

Experiment set-up:
First one exercise book is placed between the magnet and the paper clip, then two, and so on. The children realise that a magnet works through paper (here an exercise book). By experimenting, they realise that a magnet only works through a certain number of exercise books.

Then the thinnest cork disc / wooden disc is used first, followed by thicker and thicker ones.

Here the realisation is similar.

The children have the idea to repeat the experiments with stronger / weaker magnets and observe carefully.

They found that a magnet can attract iron through paper, cork and wood, depending on how strong it is and how thick the materials are. They also swapped magnets with each other in between to try out whether the other child’s magnet really attracts better or worse.

They had the most fun with experiment 3.

EXPERIMENT 3:

Material:
Water, a little boat (=small cork plate with a paper clip attached to the bottom with a drawing pin), transparent container, magnets.

Experiment set-up:
A boat floats in the water container. The children try to guide the boat with a magnet.

At the beginning, I had five boats floating in a transparent bowl. Three of them had paper clips and two boats had no paper clips. I told the children that some boats could sail with „magic power“ and demonstrated this.

Each child was then given his or her own shell and a boat. The „magic“ worked for three children, but not for two. They had the idea to take a closer look at the boats and noticed that three boats had paper clips under the cork and the other two did not. After we had completed the rest of the boats with paper clips, the children used magnetic force to move the boats through the water for about 10 minutes.

The children realised that the magnetic force also goes through the water. By adding water, it became clear that the magnetic forces are not sufficient when the distance between the magnet and the iron becomes too great.

Unit 3: How do the poles of a magnet relate to each other?

Objective:
The children realise that magnets have poles with certain properties and that the attractive and repulsive forces are strongest at the poles.

Material:
Different types of magnets (bar, disc and horseshoe magnets), iron filings, one or more compasses.

As an introduction to the new unit, I had placed Brio train carriages on a wooden track. This way the children could experience that there are different magnets attached to the wagons. Only some attracted each other and thus connected the wagons, others repelled each other and the wagons moved a little bit apart on the track.

EXPERIMENT 1:

Experimental set-up:
A bar magnet with red/green markings is hung horizontally from the back of a chair with a string. (On some magnets the poles are also marked with an embossed S and an N).

I explain to the children that the green side of a magnet is the south pole and the red side is the north pole of the magnet.

After-the magnet had balanced itself, all the children realised that no matter how many times they moved the magnet out of its direction, the ends (the poles) always turned back to the same position, so that its ends (poles) always pointed in the same direction.

The question arose:
Why is that?

I then explained that our globe itself is also a huge magnet. The magnetic forces are strongest at the poles of the earth. The pole of a magnet that is attracted to the north pole of the earth is called the north pole of the magnet. A compass is built so that its needle always shows where north is on the earth.

EXPERIMENT 2:

Experiment set-up:
1 compass (red-green magnetised sheet metal strip, about 0.5 cm thick, 10 cm long, resting on the tip of a needle) was placed on the table so that all the children could see it clearly. The children pushed the compass needle lightly, observed it and described its behaviour when it stopped.

They noticed the similarity in behaviour between the suspended magnet (from experiment 1) and the compass needle, which also always settled in the same direction.

EXPERIMENT 3:

Experiment set-up:
Iron filings are poured onto a sheet of paper. The children try out with 4 bar magnets how the filings are attracted. They observe and describe the respective behaviour of the iron filings.

The children had a lot of fun with this experiment. They investigated what happens when two like poles are held towards the iron filings and what happens when 2 unlike magnets meet above the iron filings. Sigrun then came up with the idea of holding a magnet under the paper.

Through prolonged experimentation with the magnets, the children found out that the iron filings always contracted, „gathered“, where a north pole and a south pole acted on them at the same time. The filings then lay between the poles.

If they held two equal poles (2 south poles or 2 north poles) near the filings, then the lines that formed the filings curved outwards, away from the poles.

As Janek’s mother reported to me, the day after the third unit,
her son played „Magnets“ at home for over 2 hours,
he replayed the units.

The mother could only with difficulty stop him from calling me after 10 pm to ask for the name of the „powder“. He could not remember the word iron filings.

Visit to the Magnet Museum:

Fortunately, there was the Magnet Museum in Dortmund-Aplerbeck near us. The visit there was a worthy conclusion to the series of experiments.

The children enthusiastically accepted the offer to magnetise iron themselves under the guidance of a museum employee.

Even at the end of the almost two-hour tour, the children still showed very good concentration and attention. For all the children it was clear that they wanted to visit this exhibition again soon with their parents.