If you go into Dr Mike Spearpoint’s office at the University of Canterbury and quietly stand still, you can hear lots of beeping noises. If you ask him what the noises are, he will tell you, “They are my smoke alarms.” Mike has cupboards packed with working smoke alarms.

Mike’s research project has been going for 12 years. This project investigates the long-term performance of batteries or back-up power supplies. People want to know how long their batteries will last. They don’t want to have to change smoke detector batteries too often.

Some companies have said their batteries will last 10 years, so Mike decided to test it out. He collected a large number of different sorts of batteries from different companies. Then he stored them in cupboards in his office for 12 years!

Nature of Science

Scientists are always enquiring – asking themselves questions and thinking about how they can improve things.

Every month, Mike checks the alarms to see which ones have stopped working. He replaces the batteries and puts the alarms back. He then records the data in a journal so he knows which batteries have lasted the longest.

How long do they last? Mike says cheap batteries don’t last very long at all. More expensive batteries have lasted 10 years, even 11 years.

Mike is working to find out which smoke alarms are the easiest to use. They need to be attractive too – some people won’t use them because they think they look ugly.

Mike thinks about things that could extend the life of smoke alarms. He wonders about fitting the smoke alarm to the mains power supply so you wouldn’t have to worry about changing batteries. But what if the power supply is cut?

People do unsafe things when the power stops working. When lights and stoves are not working, people light candles and use gas burners for cooking. If a fire started, an alarm connected to the mains would not work and would not warn you.

Mike wants people to be saved from fires. He believes we all need to think about putting smoke detectors in our homes and to use expensive batteries that will last longer.

    Published 9 November 2009