Asked by: John Radford, High Wycombe

Advertisement

Tears and sweat both have approximately the same salinity, but sweat contains oils and hormones that could irritate the eyes. The sweat that runs into your eyes has also run over your hair and forehead first, so it has had plenty of opportunity to pick up dust and grime along the way.

Advertisement

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.

Authors

luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.

Advertisement
Advertisement

Sponsored Deals

BBC Science Focus Magazine Subscription Offer

May Half Price Sale

  • Save up to 52% when you subscribe to BBC Science Focus Magazine.
  • Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
  • FREE UK delivery.
  • Stay up to date with the latest developments in the worlds of science and technology.
SUBSCRIBE NOW
Advertisement