Worms are hugely important on land and in the ocean. It may be tricky to do this activity using marine worms and sediment, and so this activity uses earthworms to show the principles involved. The use of different layers of soil and sand makes any mixing performed by worms more obvious. By putting food for the worms on top of the soil layers, students will be able to observe how nutrients are brought down into the soil.

Preparation

There are a few preparation steps for this activity. All of these can be done with children or by an adult independently. Including children is great for learning but will extend the length of the activity. Detailed step-by-step guidance is given below.

• Cutting the bottle - this can be done in advance as cutting into plastic bottles can be tricky for younger children, and supervising adults may wish to tape the sharp edges.
• Gathering the soil - it is best to use soil from the area that you are collecting the worms from.
• Gathering the worms - worms (and soil) are easier to find after wet weather, and in darker, shady places. Dig a hole in the soil or look under stones and pots.

Activity steps

1. Make your wormery by cutting the top quarter of the bottle off. If you are finding it difficult to cut the bottle, try pinching it to cut a small hole, and then cut round the bottle from there.
2. Cut a small slit in the top in the top section of the bottle (see diagram), so it can fit over the top of the bottom section.
3. If the cut edges of the bottle are sharp and could cause injury, then tape the edges.
4. Fill the bottom section of the bottle with layers of soil and sand, with each layer between 2cm and 3cm.
5. If the soil or sand is dry, spray each layer with water as it is put in.
6. Leave about 5cm between the top of the layers and the top of the bottom section of the bottle.
7. Add four worms to the top of the soil.
8. Add food for the worms on top. This can include (dead) leaves, grass, or vegetable peelings (potato and carrots are good, citrus peel or onions are not to be used).
9. Place the top on, and then cover the bottle with the black paper.
10. Put your wormery in a cool, dark place, such as a cupboard, and observe it daily, removing the black paper to see what the worms have been up to.
11. Release the worms back into the habitat you found them after a week.

Activity materials

• 1.5 – 2 litre clear plastic drink bottle
• Scissors
• Tape (optional)
• Soil
• Sand
• Worms
• Worm food such as leaves or vegetable peelings
• Black paper
• Water spray
• Digging tools / trowel / scoop for collecting soil and filling the bottle

Worms are amazing creatures. During this investigation, you will observe how they help soil and plants in three main ways. Their burrows help water move from the surface deeper into the soil. Worms eat dead leaves, grass, and other vegetable matter and bring this food into the soil. Through mixing the different layers in the soil, worms help to bring nutrients into deep layers of the soil.

In the ocean, many worms perform the same role, keeping the muddy or sandy sediment healthy. Here are some of the ways that worms help keep the ocean healthy.