There are many root types in nature. Plant a garden with grasses, carrots, radishes and onions. Pluck them out when at their peak to examine the different kinds of roots. Alternatively, pull out a few different kinds of plants already growing in your backyard and identify their root type with the vPlants chart linked below. Kinds of roots include corm (or bulb), taproot, fibrous, rhizome and tuber. Ask kids why they think these plants have such different roots.
This activity shows that room for roots to grow is important for the overall health of a plant. Find several containers of varying size, as small as 2 inches tall and 2 inches in diameter, without holes in the bottom. Have kids fill the containers with vermiculite or perlite. Plant the same kind of seed in each one. Feed the plants the same amount of fertilizer and water. Watch the plants grow for one month, or until a difference is noticeable between the smallest- and largest-container plants. Have kids exhume the plants and examine them. Younger children can simply look at the plants, while older children can measure and record the difference in stem and root growth for each plant. Ask the kids why they think plant growth varied from pot to pot.
Soil type can affect how well roots grow. Find four containers of the same size with no drainage holes, such as empty quart yogurt containers. Have the kids fill each with a different soil type: pure sand, half sand and half clay, pure clay, and an equal mixture of sand, clay and vermiculite. Plant the same type seeds in each pot at the same depth. Ask the kids what they think will happen to the roots in each type of soil. Watch the plants grow for two weeks. Have the kids exhume the plants and examine the roots and overall plant health.
This activity shows that roots not only grow downward, but also follow the force of gravity. Fold a bean seed in a moist towel and wrap it with foil. Tape the packet to a record player and turn the machine on to spin at 78 RPM. After five days, open the packet on the turntable. Ask the kids which way the baby root is facing and why they think it is facing that way. The root should be facing outward rather than down, since the turntable created a simulated gravity with its centrifugal force.