This summer, turn your backyard into a science lab for your children to learn about the great outdoors. Nature provides an infinite number of ways for kids to practice close observation, recording details, hypothesizing, conducting tests, and drawing conclusions – all skills professional scientists use during experimentation. With a few basic materials and a curiosity for the world around them, kids will learn their backyard is a scientific playground!
Working Worm Compost
Do your children know how earthworms affect soil? They can make a worm compost jar that will allow them to see how worms make tunnels, mix soil, and eat food. You’ll need one large wide-mouth mason jar and a smaller container that fits upside down inside the jar. The smaller container is used to keep the worms from tunneling inside the jar’s inner space where they can’t be seen. Layer the remaining space with soil, alternating between dark garden soil and light sandy soil. Make each layer about an inch deep. Moisten the soil, if necessary, with a few drops of water. Fill the worm compost jar with about six worms that children have found in the garden or under rocks and leaves. Top the jar off with a few scraps of vegetables and blades of grass. The worms will require air in their habitat, so don’t use the jar’s inner lid. Instead, replace it with black construction paper that has been pierced with several pinholes. Secure the paper in place with the jar’s screw-on ring. Although earthworms have no eyes, they’ll sense the sunlight. To thrive, they’ll need to be surrounded by darkness. Affix black construction paper around the jar to simulate darkness. Keep the jar in a cool place outside or bring the worm compost jar into your basement.
Each day, remove the outer wrapping to see what changes have occurred. Eventually, the worms will begin mixing together the two soils as they tunnel and creating castings from digesting the food they eat. Each time kids check their progress, they can monitor the moisture of the soil, adding water as needed. After a few days, return the worms to the garden or flowerbed.
Preventing Soil Erosion
Have your children seen how rain washes away soil that lacks protection? They can conduct an experiment that will show how grass can prevent soil erosion. First, remove a large rectangular section from three plastic 2-liter bottles. Place each bottle on its side and fill each with soil that is about an inch or so deep, keeping it below the bottle’s cap. Now, set one of the bottles aside. Top the second bottle’s soil with leaves, grass clippings, and a few twigs. Atop the third, sprinkle grass seed and water. This third bottle needs special attention: warmth, sunlight, and a daily sprinkling from the watering can. After almost two weeks pass, this plastic bottle should have a fresh carpet of grass. Once it does, it is time to see which of the bottles will show the most evidence of erosion.
Fashion a handle from a length of cord to a plastic cup. Hang this over one of the plastic bottle’s cap. Do this for each bottle and then remove each one’s bottle cap. Now, slowly pour water into each bottle and watch as the water flows through the bottle and out the uncapped opening into the suspended cup. Your child will see plenty of soil in the cup of the bottle that only held soil. Less will be in the bottle with the mulch covering, and lesser still in the bottle of soil and grass. Once this has been completed, children can remove the grass from the bottle and examine its root system. Plus, they can give the grass a firm squeeze to release water the grass has held.
These last two experiments will have shown children that water is vital to life. It is a necessity, but too much is detrimental. Children can learn on the farm and in the garden that fruits and vegetables grow poorly if they don’t get enough water. Children can construct their own rain gauges to see if it’s time to turn on the sprinkler.
On average, your backyard garden should soak up about an inch of water a day. Light showers and heavy storms can produce drastically different amounts of rain. Rain can be collected in a straight-sided mason jar with a funnel made from a one- or two-liter plastic bottle. Size it just right by putting the bottle into the jar with the cap end downward. With a marker, draw a line along the bottle’s edge where it meets the jar. Cut the bottle on the line and gently replace it so its top edge is slightly above that of the jar. The funnel captures the right amount of water since it’s the same diameter as the jar. The funnel also helps slow the rate of evaporation. The rain gauge should be placed in a wide-open space where the rain it collects will fall from the sky and not a rooftop, nor should it be caught by a tree or canopy. Kids can practice estimating how much rainwater storms produce. When the skies clear, they can use a ruler to measure the water’s depth in the jar.