If a spirit level was 200 miles long would it follow the curvature of the earth or go straight off of the edge of the earth?

Answer 1

It will follow the curvature of the earth. More information In surveying a level line is optically straight and although parallel to the horizon at the point of origin would diverge away from the surface of the planet as the distance increased. Try a straight edge against a football. A horizontal line will follow the surface of the planet and is therefore quite different to a level line although the two may be considered to be indistinguishable for short distances.

Answer 2

What you’ll need

2 Aluminum cans, empty and washed out

2 Circular pieces of wood of equal size (diameter between 1 and 2 ft. works best)

4 Small Rectangular pieces of wood*

1 Large Rectangular piece of wood**

Water-Based Paint

Wood Glue

A strong, multi-purpose adhesive

Saw

Sand paper

Knife

* small pieces of wood should have: length = 1.5 x radius of circular wood and width = height of the aluminum cans

** large piece of would should have: length = at least radius of circular wood and width = at least diameter of circular wood, a thickness of at least 1.5 in. is also desired

Building Your Birdhouse

1. Cut out the two circular pieces of wood, including two eye holes in one the same shape as the aluminum cans (trace them to be sure). Sand them afterwards to eliminate any rough spots. These pieces will serve as the front and back of the face respectively, so paint 1 face of each a color of your choosing (including a nose if you so desire!).

2. Cut the smaller rectangular pieces to the appropriate size.

3. From the larger rectangular piece you will be cutting out the mouth which will eventually serve as the bird feeder. Draw the shape of the mouth (an elongated “U” shape) onto the wood and cut it out, being sure to sand it afterwards. After you have your completed mouth, use the knife to indent the top so that birdseed may collect there without spilling out.

4. Cut out the tops of the 2 aluminum cans, and be sure to eliminate any sharp edges.

5. Use the adhesive to secure the cans in place at the openings you cut in the circular wood, and then, using the wood glue, create a box around the cans that is glued to the unpainted side of the aforementioned piece of circular wood

6. Use the wood glue to then glue on the back of the face and the mouth of your smiley.

7. Fill the smile with birdseed and you’re done!

If you want the birdhouse to last outside longer you can use a water-based sealant on all of your wood pieces. Additionally, please make sure that whatever wood, glue, adhesive, paint, and sealant you use it is safe for the birds to be around, and enjoy your new birdhouse!