Compile several sounds on your computer or a CD that represent night and day, such as birds chirping, owls hooting or crickets sounding. Play these sounds and ask children to decide if each sound is occurring during the nighttime or daytime. You can make this more of a competition by splitting children into teams of five or six and having each group make a guess, giving points to the students who guessed correctly.
Visual clues can also help children distinguish whether it is night or day. Bring in certain items that are used during the day (for example breakfast cereal) and items used at night (such as pajamas or slippers). You can also show pictures of animals associated with the nighttime or daytime, such as owls or bats for night and birds and other mammals for the day. Ask students to guess if the objects or animals are associated with day or nighttime.
Give children a list of things that are done during the day and then a list of things done at night. You can do this by writing it on the board, bringing in visuals for children who do not yet know how to read or saying the list out loud. Have the children listen to the list or look at the visuals and decide if the sequences of events occur during the nighttime or daytime. After you have established events that happen in the day and nighttime, ask students about certain individual activities and whether these occur in the day or night.
Have children stand up and demonstrate the relationship of the sun and moon, effectively showing the class why it is day and night. One student will "play" the Earth, standing in the middle of the classroom while two other students "play" the sun and moon. The moon will "chase" the sun around the Earth, but always stay at an equal distance. Children can also play this in groups of three with the moon trying to catch the sun. When the moon "catches" the sun, it is the sun's turn to "chase" the moon.