How to make a waste time hourglass? - For this you will need 2 identical empty water bottles (small), wide tape, sand, funnel (also paper), sieve, small plastic bag. The children will do it 2 times to make the sand finer. We will divide the bottles. We insert the upper part into the lower part and glue it. We glue, growing in size with the swelling of the bottle. We make a hole in the nylon (small - depends on how fine the sand is). We pour sand into it before decomposing the two parts of the second bottle. Finally we join the two bottles together and... done! The children will use an hourglass for how long it may take for the sand to run out. Dear friends, you can share how the hourglass is to someone, if you don't have another one.