![Question of the Week - From the Naked Scientists show](https://d3dthqtvwic6y7.cloudfront.net/podcast-covers/000/034/494/small/question-of-the-week-from-the-naked-scientists.png)
Summary: Why are copper compounds so colourful? In this week's Question of the Week we find out how one metal can have so many colourful compounds, as well as a distinctive green flame. Plus, we ask why dreams are so hard to remember, even the really good ones, and how can a frog can breathe through its skin, with no help from lungs or gills?