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The Scientific Method:

Scientific Method - A Flow Chart

The scientific method is one particular way to ask and answer scientific questions by making observations and doing experiments. Some people argue that there is no such thing as 'The Scientific Method' - make up your own mind:

The steps of the scientific method are to:

No matter what your method is, it is important for your experiment to be a fair test:

A fair test means that you should set up your experiment so that everything is fair. You should only change one thing at a time, and note down the results. If you change more than one thing at a time, you can not tell which thing (variable) it was that affected the results.

You should record your observations in a Table of Results


Comparison of conductive materials using MakeyMakey (see the experiment below):

Switch Material Sound YES/NO Comments
Finger YES I had to watch the MakeyMakey howto video to work this out http://makeymakey.com
Aluminium foil

Table 1: Comparing conductive materials used to activate electrical switch

Write the reason you think that some things work and some things do not work:

What other kind of experiment would you like to do using a switch:

Practical Experiments with Switches

A switch is a device that is used to OPEN or to CLOSE a circuit. Many simple switches, are made from two pieces of conductive material (for example; metal), that made to touch to CLOSE the switch (to turn the circuit ON), and pulled apart to make the switch OPEN (to turn the circuit OFF).

  • When a circuit is OPEN, individual components may be active but the circuit as a whole is not operating.
  • When a circuit is CLOSED, both the individual components and the circuit as a whole should be operating.

Surprising Facts About Switches

It May Surprise You To Know… that computers recognise only two numbers, zero and one. In computers the numbers are represented by electronic switches. An OPEN switch represents a zero and a CLOSED switch represents a one. With enough switches, almost anything can be stored and represented as numbers. Another name for these computer switches is “bits”. The 'bits' are stored in computers' memories and recalled using the keyboard and an application.

It may not be obvious, but it is true to say that almost all of shared human knowledge is now stored in switches. That is one reason why it is so important to understand how switches work!

Why switches are useful

Circuits without switches are not very useful because, without a switch, you would have to actually remove or add a component to the circuit to turn the device on/off.

Turning devices on/off without using a switch is also often unsafe.

Make or Break - Practical Experiments with Switches

Adding or removing a wire may have the same effect as CLOSING or OPENING a circuit.

You can think of a switch as being a way to MAKE or BREAK a circuit (in the same way that adding or removing a wire can make or break a circuit).

Opening/closing a switch or adding/removing a wire, may have the same effect, but using a switch is usually easier, more efficient and safer.

To make a circuit, use one or two Alligator Clips to connect objects to the circuit. To make a simple switch, almost any metal object will work. Simply connect the object to the circuit using alligator clips. You may also create a switch using a MaKey MaKey board and some other object - for example, using an apple. If the apple is conductive, connecting alligator clips to the apple will CLOSE the circuit and the computer thinks that someone has pressed a key on the keyboard. Because a computer key is only a switch, it is true to say that you are using an apple and a Makey Makey to create a switch.

Circuit with switch CLOSED

Magnetic Switches - Reed Switches

Try connecting a reed switch using your test lead alligator clips.

Use the magnet to CLOSE the circuit and turn the torch OFF and ON.

Record your results in the results table.

Electrical Conductivity

Try creating a simple switch using some conductive materiala and your test lead alligator clips.

Connect the material into the circuit and try to turn the torch OFF and ON.

Record your results in the results table.

Electronic Switch

You can use the Makey Makey as an electronic switch. Find four items to connect to your test leads.

Try connecting each item to CLOSE the circuit and use the Makey Makey to play a sound or enter a key on a computer.

Record your results in the results table.

Closed Circuits

Collect four items to connect to your test leads. Try connecting each item to CLOSE the circuit and turn the torch OFF and ON.

Record your results in the results table.

Electrical Circuit Symbols

Circuit Symbols for common components

Circuit Diagaram example

Musical Birthday Card

Musical Birthday Card

Working with LEDs

Most bulbs and globes are being replaced by devices called Light Emitting Diodes (LEDs). Unlike bulbs/globes, LED's have a positive and negative lead and must be connected the right way round in a circuit (bulbs and globes don't care which way round they are connected in relation to positive and negative. LEDs also require an additional component called a resistor to limit the amount of electrical energy flowing through them. Here are some examples of what LED's look like:

More Challenges

Tired of boring old wires and buzzers….

learn/circuits/example-activities/switch-conductivity.txt · Last modified: 17/07/2017/ 11:33 by