Include magnifying glasses so that students can observe a variety of objects from a different view. Try to have several sizes of magnifying glasses available. Allow each student to make a fingerprint using a stamp pad and a piece of paper. Instruct the students to study each other's fingerprints to see how different they are. You could also give a lesson on the meaning of "unique," and use the example of how no two people in the world have the same fingerprints.
Three year olds love to play with magnets. Put several sizes of magnets in the science center, and be sure that some of them attract each other while others repel. Also include items that the students can test to see if they are magnetic. For a fun experiment, tape magnets on the front of toy cars. The students can then see how the magnets affect the movement of the cars. Students can also try to make one car move by using a magnet on a different car.
It can be difficult for 3 year olds to understand how light works because light is not concrete. Prisms allow them to see how light is made up of different colors, and it helps them to understand how rainbows are made. Place prisms in the center, and allow the students to explore how to use them. Then, instruct them to draw a picture of what they saw when they put the prism in the light.
Teach the children about reflections using mirrors. Leave several types of unbreakable mirrors in the center, including compact mirrors, mirrors with handles and a stand-up mirror. Include other shiny objects that show reflections, such as flatware, silver appliances and foil. Instruct the students to hold the mirror at different angles in front of them to show that the reflections changes as they move the mirror.