Before you toss out those avocado seeds after making a batch of guacamole, consider using one or more to grow an avocado plant in water. This is a popular and simple project for school children. Watching the seed spout and grow into a lovely green plant is a rewarding nature project. Eventually the seed can be planted in soil.
Remove the avocado seed from the fruit and rinse in water.
Hold the avocado seed so that the pointy end is up and the curved end is at the bottom. The pointed end will be referred to as the top of the avocado seed, and the curved end as its bottom.
Insert a toothpick on the side of the avocado seed, half way between its top and bottom.
Rotate the avocado seed a third of the way around and insert the second toothpick, half way between its top and bottom.
Rotate the avocado seed another third of the way around and insert the third toothpick, half way between its top and bottom. There should now be three toothpicks, equally spaced, along the center of the avocado seed.
Fill the glass with water.
Set the avocado seed in the water with the pointy side up. The lower half of the avocado seed should be submerged in water and the toothpicks should be hanging over the rim of the glass, holding the avocado seed in place so that it does not fall into the glass.
Set the glass in a sunny window and keep the bottom half of the avocado seed in water at all times.