Playing catch is a simple way to introduce the concept of aim and force. Make a game of catch interesting for preschoolers by using a variety of balls. Start off by having children toss soft balls, such as beach balls, back and forth. Make the game more challenging by using small balls or playing with water balloons outside on a hot day. Ask children to compare all the balls they used and conclude which was easiest to throw and which was hardest.
When children are trying to throw an object into a specific container, they'll get to experiment with using over- and under-handed throws to see what works best. Cut off the bottoms of plastic-handled milk jugs and cover the cut edge with masking tape. Working in pairs, ask one child to throw a bean bag into the open end of the jug while the other child holds it up. Have each child move back a few inches after each throw to make the game gradually more challenging, then switch so each child gets a chance to throw the bag.
Teach children about recycling while giving them throwing practice. Gather a variety of materials that can be recycled, excluding any materials with sharp edges, such as metal cans. Set up and label boxes for each type of recyclable you have, such as plastic, paper and metal. Line children up several feet from the boxes and hand each child one item. Ask the child to throw the object into the correct bin. If he misses, let him try a second time.
Help children test their own strength and learn about simple experiments by heading outdoors with a soft ball. Standing in an open area, ask each child to throw the ball up in the air as hard as she can. When it comes down, let another child help you measure the distance from where the thrower is standing to where the ball came down. Hand her the ball again and ask her to guess what will happen if she throws it softly in the air. Once she's done this, measure the distance again. Children should learn that the harder they throw, the further the ball goes.