Eighth grader Chase, from Canada, asks for examples of things that are horizontal.

Hi Chase,

It's funny that you should ask this question today, because when I was teaching my high school Physics class today, one of my students kept mixing up "horizontal" and "vertical." So before I give examples of horizontal, I thought I'd try to give everyone some helpful hints to remember the difference between horizontal and vertical.

If something is horizontal, that means it's lying down flat, and if it's vertical, it's standing up straight.

So how can you remember the difference? Well, I have two suggestions:

1. Remember that the horizon (the place far off in the distance where the land meets the sky) is flat. The horizon is horizontal. And no, it's not a coincidence that the word horizontal contains the word horizon!
2. Your vertebrae are the bones in your spine, and your spine stands up straight. Vertebrae, vertical. Both start with with "vert" and both are standing up straight.

So if you can remember one or the other of those things, you should be able to remember the difference between vertical and horizontal.

Okay, so now, to answer your question - what are some things that are horizontal?

• The horizon
• A table top
• A floor
• Roads (except on hills)
• The seat of a chair
• You, when you're sleeping! (and then your vertebrae aren't vertical!)

Some things that are vertical?

• Walls of most buildings
• Doors
• Cliffs
• Towers (except the leaning tower of Piza - that one is neither horizontal nor vertical!)
• Trees
• You, when you're standing up!