Propeller and Globe Circuit

Propeller and Globe Circuit

Can you get the propeller and globe working together?

Suitable for kids aged 7+, with adult supervision

CAUTION

  • The light globe is glass and misuse may cause it to break, resulting in sharp pieces that could cut skin. Use carefully.
  • Do not hold the wire on the battery for long periods without removing it. The wire and/or battery terminal may get hot.
  • Do not put spinning propeller near peoples faces or hair. Hair could get tangled.
You Need:

What to do:
  1. Before you start, ensure the globe is screwed into holder and the two wires are connected. Likewise, the motor attached to the propeller should have two wires connected (see Light It Up and In a Spin experiments).
  2. Now that you have got the propeller and globe working on their own, the challenge is to get them working from the same battery at the same time. It is tricky holding everything together with your fingers!
  3. Once you have completed this challenge, can you think of a different way, or circuit, to get them working together?
  4. Joining two batteries together gives extra power.

Why is it so?

There are two main ways to get the propeller and globe working together from the same battery. The first is by making two separate circuits (or paths) by holding the free wires from the globe and propeller to the top and bottom terminal of the battery together. The electricity flows at full power through both circuits.

The second is by making a series circuit, by holding one free wire of the globe to a battery terminal, then connecting the other free wire of the globe to a free wire of the propeller. The other free wire of the propeller needs to be held to the free battery terminal, completing the circuit. The electricity flows through one component and then the other. Because the push in volts is shared, the bulb glows dimmer and the propeller spins slower.

In a parallel circuit, the components are connected to the same circuit, but not one after the other, so the electricity flows at full power through all components.

Globes, globe holders, propellers, motors and wire are available from the science supply section of this website.