Prematurely overcome by the holiday spirit, we failed to send a round-up last week. Apologies for that. One of the most popular questions from that week – also with a holiday flavour – was what to do during a lightning storm at the beach. Are you safer on the beach or in the water? The discussion contains a fair bit of disagreement, but some great tips for optimum lightning-avoidance behaviour.

This week's questions started with whether the wind affects sound waves (it does, but not in the way you might expect), and whether the foods we crave are the ones our bodies actually need (let's hope so).

Here's one for the physics-minded: ever wondered why most rocket launch pads are sited near the equator? It's to make the most of the rotational velocity of the Earth's surface, which is greatest at the equator. But can you think of any other ways we exploit this tremendous energy source? So far, not many readers can.

If you've ever been caught by brambles while walking in the countryside, you might be curious why the thorns of roses and blackberries are designed to catch animals rather than repel them. Could it be that roses are actually carnivorous?

Finally, August is the month for… meteor-hunting. The Perseid meteor shower is at its height on 12 August. One of our readers reckons he can hear meteors. Is that possible?

Enjoy your weekend.

Michael (acting for Kat)

I know it would be best to go home and have a beer--but that's not my question. Given a choice: wet, sitting or standing on the beach or just barely sticking your head out of the water, close to shore: which is the safer choice and why?

As a young child, I used to love putting the shells like the ones in the picture, into my ear to listen to them. I remember being told that you hear the waves in them. I know that's not entirely true, but what exactly causes the sound we hear? And why don't we hear such sounds if we put other objects like it up to our ear?