Three-year-olds are ready to start learning about letters and sounds, the first steps to reading readiness. One of the best teaching tools for this age group is to read out loud to them. Point to each word as you read it and read the same book several times. Start having the children use context clues. Read part of a sentence and help them use what you've read, plus the picture on the page to guess the last word or words. Integrate books into the rest of your lesson plan. If you are reading a Eric Carle book that counts animals, this is a good chance to bring in science as you talk about the animal and its habitat.
Children as young as three years old are ready to start learning math concepts such as number recognition, shapes and counting. There are many opportunities during a school day to introduce math organically. Patterns are a math concept three-year-olds can grasp. Count the children out loud as they line up to go out to play. Or point out that a rhythm during music class has a four beats. This is not a time to push math, but rather to let children experience it throughout their day.
Preschool students are often very open to hands-on activities that teach science. Science doesn't have to be kept in a designated time period, either, because it is everywhere. Include science in language arts by reading books about nature, animals, water and other scientific topics. You can bring science into art by letting children make magnet pictures with steel wool shavings. Science and math go hand-in-hand. Let children play at a water table with measuring cups to start teaching the basics of size, fractions and the properties of water.
Three-year-olds sometimes have trouble transitioning from one activity to the next. Transitioning techniques are important to keeping the peace in your classroom. Give a one minute warning before the current activity ends, and make moving to the next one fun by having students do it in a silly way, such as crawling or hopping, or by using a puppet to direct them. While children this age do well with structured time, they also need lots of time to play. Build play into your lesson plans. Encourage your students to use their words and their growing vocabularies to express themselves, rather than crying or whining.