Bring fruit, pizza or other food into the classroom. Find something that splits into pieces. Grapes or olives work best because they come in bulk for a relatively inexpensive price. Hand out multiple pieces of food to the students, instructing them not to eat them. Cut one piece of food down the middle. Explain that one of these equals one half. Write the fraction on the board to show what the looks like. Cut each piece in half again so that you have four pieces. Hold up two pieces and explain that those represent one half because you have two pieces and there are two pieces left over. Encourage the students to create new variations of "1/2" with their pieces of food. Always cut the food for your students instead of letting them do it.
Give the students several pieces of white paper and crayons. Draw a circle on the whiteboard and a line down the middle. Color in one half of the circle and explain that the colored part is one half of the overall circle. Write the fraction "1/2" so that the students can see how it's written. Draw a new circle and draw lines to cut it into four equal quadrants. Color in two of them. Explain that this is still 1/2 because two parts are colored and two aren't. Encourage the students to try the same on their papers, adding more parts and using different shapes. Walk around and help students when they do something wrong, such as if the parts are apparently not equal.
Teach the students, by using the whiteboard, how to recognize 1/2 fractions even when they aren't written in that format. Tell them that a 1/2 fraction has only half the number on the top of the fraction as on the bottom, which means if you add the top of the fraction to itself you will get the bottom number. For example, in the fraction "4/8" you get "8" if you add "4" to itself. Show the students that they can also subtract the top number from the bottom. If you get the same number as the top, it's a half fraction. For example, 8 -- 4 = 4. Give them a worksheet with numerous fractions. Ask them to circle the half fractions.
Choose two students from the class. Set them on different sides of the room, one near you and the whiteboard. Write "1" on the board and tell the student that's because there's one student near you. Write a "2" under it so that it reads "1/2." Explain this is because there are two students. Tell them that you know this fraction represents one half because there are equal students on each side of the room. Run this exercise over and over with different numbers of students each time. Ask the students to identify when the fraction equals 1/2. Have them write the different fractions on the board.