Building a one minute timer is a fun project. Here are two ways to build a one-minute timer:
- Place both bottle caps together with the tops touching. Drill a hole through the caps. Attach a screw and bolt near the center of the caps.
- Drill a few small holes through both secured caps.
- Drill a hole in the middle of the side of each bottle.
- Attach the bottles to the caps. One bottle is upside down, on top of the other.
- Fill the top bottle with water, through the hole on the side.
- Time how long it takes for the water to flow through the caps to the bottom bottle. Adjust the amount of water in the bottle until it takes exactly one minute for the water to flow through [source: Schultz].
- Pour 2 cups of sand into one of the bottles, using a funnel.
- Trace the opening of the second bottle on the card stock.
- Cut out the circle and punch a hole in the middle.
- Tape this circle over the opening of the bottle that has the sand in it.
- Place the bottles one on top of the other, neck-to-neck, with the card stock piece in between. Tape the bottles together in a way that you can remove the tape, for adjustment.
- Stand the bottles so the sand is in the upper bottle.
- Time the how long it takes the sand to flow from one bottle to the other. Adjust the amount of sand until it takes one minute for the sand to flow from the top bottle to the bottom bottle.
- Secure the tape firmly, to attach the two bottles [source: wonder].