Above and Below: How a Plant Starts to Grow

Ages three and up (one 45 minute session)

$Measurements/Math$ Motor Skills

Objectives:

To observe and understand, root growth and plant development.
To learn about tubers, and roots. storage.
To learn about vegetative propagation.
To observe the movement of water through the soil.

Materials:

Root view
A Styrofoam root view unit can be purchased from the Discovery Channel Store for about $30. This has a clear panel that allows view of the soil and root growth. Alternatively, individual root views can be easily made from soda bottles. Cut the top off of the bottle and put holes in the bottom for drainage. When the plant isn’t being observed, it can be placed in a sleeve made from aluminum foil. (If darkness isn’t maintained when the plant isn’t being observed, not many roots will grow against the plastic).
Bean or Pea seeds
Radishes, potato or sweet potato, carrots and onions (An onion that has started to sprout would work great, as do old carrots that have started to get tops)
Pothos or Coleus plant to make vegetative cuttings in class
Bulbs such as tulip or daffodil (if available)
Potting soil (prefertilized) and plant labels
4 jars filled with water
knife
Plastic bag and drinking straws
Heavy cotton string (about 12 inches)
Bushel basket

Set up:

Purchase the root view pot or make one of your own.

Plant some bean seeds 3 weeks prior to the class.

Place a carrot or two in a plastic bag in the refrigerator with a moist paper towel so it will sprout. (This will take approximately 2 weeks), place a potato in a paper bag to sprout (could take 4 weeks).

Part One:

Show the Pothos plant to the children and talk about the different parts of a plant. Talk about what plants need to grow. Carefully turn the plant over holding the top of the soil, and remove the pot so that the children can see the roots. Have them look closely at the color, and the small hairs. Talk about what healthy roots should look like. Talk about the function of the roots. Use the straws to show how water is sucked up in roots. Demonstrate osmosis with the cotton string. Talk about Transpiration. Start talking about different kinds of roots. Show them the carrots, and radishes. Talk about what storage means. Plant one of the carrots in a root view, and put another in a plastic bag with a moist paper towel. (0ver the next few weeks both carrots will grow but one will live off of itself instead of soil nutrients, and shrivel). Show the children the sweet potato and potato and explain that they are an underground organ that stores energy for growing a new plant. Talk about what starch is. Talk about what a modified stem is and prove it by leaving a potato in the sun for a week to turn green. Talk about chlorophyll. Talk to the children about never eating a green potato and explain it is poisonous when it gets that way. Ask if they would like to grow a bushel of potatoes. Place a sprouted potato in a bushel basket (one from home that has sprouted will work fine), and cover it with prefertilized potting mix. Water well. In two weeks or so, the potato will have sent up shoots. When they are approximately 3 to 4 inches above the soil line, cover them again with more soil. Repeat this process over several weeks until the basket is full of soil. Continue to water and care for the plant until it flowers and then the tops die back. (This should take most of the summer). When the children dump out the basket, they should find 15 or more potatoes. Note: This is a good project to start inside around the middle of February. Then when the weather gets warm enough the basket can be put outside in a sunny spot to finish over the summer. It will break the boredom of winter and get the children excited about the up coming gardening activities. Just be sure to put something under the bushel basket to catch the water when it is inside and remove the catch basin when the plant is put outside.

Part Two:

Turn the children’s attention back to the Pothos. Explain that baby plants can start from: seeds, underground tubers, or cuttings. Using sharp pruning shears or scissors, take cuttings from the Pothos plant (Coleus plants also work well for this activity). Put these vegetative cuttings in a jar filled with water. Explain that the water will cause roots to form, enabling a whole new plant to grow. Talk about cloning and what that means.

When the plants have established a good root system plant them into soil. You can measure the length of any shoots that are growing, and plot the length on a graph.

Part Three:

As the plants grow, have the children sketch the changes in their experiment journals. The length of the roots can be monitored and measured every 2 – 3 days. If children are young, the length of a block can be used as a unit of measure. Older children can use a tape measure and graph the root length as time passes.

Questions to ask:

What does cloning mean?
Are you a clone?
How long do you think the underground tuber or root feed the plant?
Will it shrivel up as the plant gets bigger?
Will new potatoes grow above the ground or under the ground?
How do roots get the water and nutrients up to the leaves?
What is osmosis?

Glossary:

Osmosis: The passive movement of water up or down, in or out of something (like a plant) due to a gradient change.

Transpiration: The loss of water through the leaves of a plant. It turns to vapor and exits the plant.

Chlorophyll: Green pigments in plant stems and leaves – essential for photosynthesis; Where the energy from light is trapped.

Starch: simple sugars used for food; Carbohydrates!