A Microscope on the Farm

4-H Night at the Bjornstad Farm

1Ezra Bjornstad's family grows corn and hay and keeps chickens and a few dairy cows. One evening, Ms. Funmilayo Adeyemi, who works for the county farm office, brought a microscope to the 4-H club meeting in the Bjornstads' machine shed. She asked the club to collect small samples from around the farm and find out which ones were living and what they were made of.

2The club peeled a thin layer from the underside of a corn leaf and cut the tip off a corn root. Ezra's mother brought a drop of chicken blood from the vet's test kit and a thin piece of chicken skin from the kitchen. From the cows' water trough, Ezra scooped up water that looked faintly green and scraped off some of the hard white crust that forms on the trough's rim. The crust grows thicker every month as water evaporates. His sister, Liv, pulled a patch of gray fuzz from a damp hay bale and a few duckweed plants from the farm pond. Each duckweed plant is a tiny floating green oval about 3 mm long.

3Ms. Adeyemi explained that most people cannot see anything smaller than about 0.1 mm, or 100 µm, without a magnifier (1 mm = 1,000 µm). She showed the club how to measure things on the microscope's scale. At high power, the duckweed was packed with hundreds of small green boxes, each with a wall around it. A gray fuzz thread about 600 µm long was divided by cross walls into many long cells. In the trough water, tiny green cells swam around on their own, and the tiny rods split in two. By the next morning the dish of trough water held many more of both.