Fun Science Activities on Life Cycles for Kids

This image shows the life cycle of a typical butterfly.

A life cycle is a series of developmental changes that organisms undergo during their lifetimes. While some organisms have clearly defined life cycle stages, others---like humans---grow gradually without much variation in their physical structures. For kids, there are some fun science activities about life cycles that can help expand their knowledge of the subject.

Observing and Documenting Life Cycles

One life cycle activity idea is to observe an organism's life cycle while in a backyard or at a park. Perhaps the best organisms for this project are butterflies and moths, as they have very distinctive life cycle stages (starting out as eggs, hatching as mobile caterpillars or larvae, growing into stationary pupae and finally emerging as winged insects). Children can find caterpillars and care for them in glass jars until they enter the pupa stage, or alternatively, they can find a pupa hanging from a branch or other object. According to Science Project, children should observe their samples and draw a timeline that documents all of the life cycle changes that occur.

Grow a Bean Plant

For this activity, each of the participants will need a cup filled with 2 inches of water, a bean, some potting soil (or compost) and a test tube. According to Kids Science Experiments, they should start by soaking their beans in the cup of water overnight. In the morning, they can remove their beans from the water and fill up the test tubes with soil, just over halfway. Each kid should then place his bean in the test tube, and cover it with more soil. By keeping the test tubes in a sunny spot and watering the soil daily, kids will be able to observe the growth of the bean plant. As legumes, bean plants have edible seeds (which are called beans) that grow in pods. Eventually, these pods will begin forming on the children's plants, allowing them to start the life cycles of their beans all over again.

Fruit Fly Life Cycles and Temperatures

Kids will need to capture approximately 20 fruit flies (split between two jars) for this activity. According to Pest World For Kids, they can accomplish this by sticking some mashed-up bananas and other fruits in the bottom of mason jars, and leaving them outside. A more advanced technique is to roll up a piece of paper like a funnel (with a tiny opening) and wedge in to the jar's opening. This will allow flies in, but not out. Each kid should then cover his two jars with paper towels, and leave them in a room-temperature location for a day or two. This will give the fruit flies a chance to mate and lay eggs. Kids may be able to observe eggs with a magnifying glass, and will certainly be able to see larvae once they crawl around. At this point, children should uncap their jars and let out the parent fruit flies. They should then put one jar in a warm place (such as on top of a heater) and one in a cold place (such as in the basement). Kids can then observe how long it takes the larvae in each temperature location to develop into full-grown, flying fruit flies.

References

• Kids Science Experiments: Watch a Bean Grow
• Pest World For Kids: Science Fair Project: Fruit Fly Life Cycle
• Science Project: Personal Observations on Life Cycle