Children can explore nature and store flowers permanently by pressing them. Take children outside to pick wildflowers or any interesting grasses that they like. Only let children pick flowers from an area that you know is safe, without any plants that have thorns or poison ivy nearby. Give each child two sheets of contact paper. Unpeel the paper from one sheet and place it sticky-side-up on a table. Children then can position their flowers on the contact paper. Remove the paper backing from the second sheet and position it over the first sheet. Let children press the page down over the flowers to seal the contact paper.
Ask each child to bring in a clean glass jar with no labels. Explain that you're going to make containers to catch and look at insects. Give children acrylic paints and paintbrushes so they can decorate their catchers, but explain that they shouldn't cover the whole jar with paint or they won't be able to see the bugs. Punch small holes in the jar tops. When the paint is dry, take children outside and see if they can catch any insects in their jars. Although young children likely can't catch flying insects, they should be able to at least find ants to scoop up. Screw on the jar tops and let children look at their bugs up close before releasing them.
Let children experience how the wind changes by creating their own wind socks. Give each child a paper plate. Trace a circle about one inch from the edge of the plate for children to cut out. Some 3-year-olds will be able to do this on their own, while others will need help. Punch a hole on either side of the plate and tie on a string handle. Let children tie crepe paper streamers or long pieces of yarn all around the plate. Take the children outside. Explain how they can tell which way the wind is blowing by watching the streamers move.
Hang bird feeders outside a window and young children will be entertained by visiting birds all day. For a simple bird feeder, give each child a pine cone and a bowl of peanut butter. Using plastic spoons or their fingers, children can smear the entire cone in peanut butter, then roll it in bird seed. Tie a piece of string around the the top of the pine cone and hang it outside from a tree or a metal stand. Ask children to observe what creatures they see eating from the feeders.