Make a Sand Timer

Making your own sand timer is a good way to teach children about time, gravity, and math. This is a safe project that doesn't involve any scissors or cutting edges, so even the smallest children can safely help. You can save time and make sure you're ready to begin the project immediately by peeling the labels off the soda bottles and cleaning them, then leaving them out to dry completely both inside and out, in advance.

Things You'll Need

• Two small soda bottles of equal size Clean, dry sand Tornado tube or twist tube Stopwatch Marker

Instructions

1. Peel the labels off the soda bottles. Wash them inside and out then let them dry completely; this may take up to several days.

2. Fill one of the clean, dry soda bottles half full of clean, dry sand. Screw one end of the tornado tube or twist tube into the top of this bottle, then screw the other bottle into the free end of the tornado tube. You should now have both bottles joined together at the neck by the open tube.

3. Turn the bottles over so the bottle with sand in it is now on top. The sand will flow down into the bottom bottle. Use the stopwatch to time how long it takes.

4. Upend your sand timer again and time how long it takes all the sand to go through once more. As the sand falls, mark the sand level in the top bottle at regular intervals. For example you could mark where the sand level is every ten or fifteen seconds. Keep marking until all the sand has run out. Now you can use your homemade sand timer to actually tell how much time has passed by counting interval marks.

Tips & Warnings

• This is also a good project for teaching basic math and multiplication skills by counting or multiplying the timed interval marks. You can buy clean dry sand at craft stores. Experiment with different kinds and sizes of sand grains to see which flow fastest or slowest.