I bought an infrared thermometer to diagnose my central heating system but for £8 it is great for anyone who is interested in physics. It measures the infrared that that is emitted from a surface to get the temperature. Different surfaces emit different amounts of infrared. To promote getting an accurate reading I stuck a white postage label on the copper pipes and took the reading from those. I then checked against other thermometers. It was correct to better than 0.5C. It think this is as good as devices that are 10x the price.

The stock of this product in Maplins is very old and the batteries were dead, like many small electronic devices it takes CR2032 which I always buy in packs of 10 from eBay.