Farm animals seem to hold a special fascination for kids. Unlike zoo animals, it's possible to get up close and personal with domesticated creatures such as chickens, sheep, pigs, goats and cows. Kids are also interested in learning about the food products these animals provide -- milk and eggs especially. Farm animals provide a good opportunity to introduce some basic science concepts to preschoolers as well. Best of all, most of these activities are done indoors -- and that means no stinky barnyard.
Once you have explained that milk comes from a cow's udder, you can begin to experiment with it. One of the simplest activities to assign pre-K kids is that of churning butter. Give each child a clean glass jar labeled with their name -- baby food jars are perfect for this. Pour heavy cream to fill the jar about 3/4 full. Screw on the lid as tightly as possible. Now let the children shake their jar. It could take a lot of shaking, and little arms may get tired, so feel free to take some breaks. But sooner or later, the fat and the whey will separate. Pour off the liquid whey -- you can let them taste it if you like, or use it for painting later. Each child will now have a jar of their own hand-churned butter. They can take home the butter or taste it right in class if you have crackers and table knives at the ready. Hint: Add a pinch of salt. You can use this activity to discuss solids and liquids, to learn measurements -- try measuring the cream before and the butter and whey after, then compare -- or just discuss the components of milk and its origin.
Sometimes the best ideas are the simplest. Put out large plastic trays and magnifying glasses. Provide chicken feathers and wool or fleece for the children to study. If you like, you can also add lengths of wool yarn and even small knitted squares or woven wool cloth to the trays and talk about the process by which raw wool gets turned into strands of yarn and then into clothing.
Chicken eggs are one of the important animal products found on a farm and they lend themselves to plenty of scientific learning projects. Let your kids play egg detective with these series of experiments. Let them carefully squeeze a raw egg in their hand and see how strong it is. Discuss why an egg breaks when it's struck on the edge but stays strong when compressed. Place one raw egg and one hard-boiled egg on a table and ask kids to determine which is which. The answer: Raw eggs wobble when spun on their end, while hard-boiled eggs spin cleanly. Explain to children that this is because raw eggs are liquid inside while hard-boiled eggs are solid, and the sloshing of the liquid in the raw egg is what causes it to wobble. You can demonstrate this with a translucent plastic egg and water with food coloring. Finally, fill a clear cup with tap water and place a raw egg into it. It will sink. Take another clear cup of water, add 2 tablespoons of salt and stir until it dissolves. Add another raw egg. It will float. Explain to children that salt water is more buoyant than plain water and that other items will also float more easily in salt water such as the ocean -- including their own bodies.
Incubate a Chick
If you have time, space and equipment available, it can be quite enriching to let small children watch eggs incubate and eventually hatch into tiny baby chickens or quails. You must make sure that children are gentle with the newborn chicks, and of course you must also have a new home available for the chicks after they are about four days old. Chicken eggs take about 21 days from fertilization to hatch; quail eggs require 16 days. Depending on your incubator set-up, eggs may have to be turned manually -- this can be an exciting opportunity for children to participate.
If you can arrange a field trip to a local farm or a farm animal petting zoo, do so. Even just a visit to a backyard chicken coop works in a pinch. Let children interact with farm animals directly by feeding, touching and gently holding them. This activity requires close supervision but it's immensely rewarding. Be aware that small children may be understandably intimidated by large farm animals such as cows and horses.