2. Dan says: Titanium is strong, lightweight and unreactive, making it a prime candidate for use in high-stress situations. Alex says: Although it is a good candidate for use in high-stress situations, it is not a good replacement for a stress ball. Trust me… I know...

3. Dan says: Aluminium is lightweight and cheap, making it ideal for mass produced products. Alex says: TIN FOIL!!!

4. Dan says: Chromium is a steely-grey, lustrous, hard metal that corrodes slowly and has a high melting point. It is also odourless, tasteless, and malleable. No prizes for whoever worked that last bit out. Alex says: Is it like the chrome in my kitchen?