If you're visiting CERN, hydrogen and atom most certainly refer to particles, maybe in the context of energy production. If you're visiting Lappeenranta, hydrogen (vety) and atom (atomi) are known as much bigger particles, loaded with energy.
Vety and atomi are grill delicacies from Lappeenranta. Vety is a meat pie filled with ham and boiled egg, and atomi is a meat pie equipped with either ham or egg.
This is how to make vety:
Have a newly baked meat pie from Kesämäen Leipomo, Kesämäki bakery. Any other meat pie (e.g. the one in the picture) is fake.
Cut the pie into half and heat it up in steam. Microwave oven won't do it.
Insert ham and egg after warming up the meat pie. The egg should be boiled - fried egg would be a sacrilege!
Wrap into paper (not into a napkin but into rustling paper) and eat while warm. Don't spoil with spices.
The hardest part for home-made hydrogens and atoms is the meat pie: Kesämäki bakery is the only producer for those. I was wandering in Stockmann Tapiola, and I knew I'm not gonna find the real thing, but I kind of expected to find something similarish - but no! There were only full corn meat pies and rye meat pies. I'm kind of happy that consumers are nowadays more health oriented, but come on! Who wants to have a healthy meat pie!?!
You'll get the only real hydrogens and atoms at a grill kiosk at Lappeenranta harbour or market place.