An antonym is a word's opposite, such as "happily" and "unhappily." Those words became opposites due to the prefix "un-." Other words can become opposites by adding prefixes. Divide the kids into two groups. Give each group strips of paper that have verbs on them like "tied" or "agree." Have each group write a simple sentence on a sheet of paper using their choice of words from the strip, and then switch sentences with the other group. Each group must change the other group's sentence into the opposite of its meaning using prefixes. For example, if a group wrote "I tied my shoes today," the other group could turn the sentence into "I untied my shoes today."
For this activity, buy a variety of square and rectangular shaped blocks. Using masking tape levels, cover the square blocks with six different prefixes each, and the rectangular blocks with a base word on each side. This activity allows kids the freedom to build real walls of prefixes and base words. Make sure that each wall is made of real words. For example, a square block with the prefix "dis-" written on it can be placed next to a rectangular block with "appearance" written on it to create the word "disappearance." See who can build the largest wall. To make another game out of this activity, roll the square blocks and match whatever lands face-up to a base word block.
Each flip book should consist of six to ten blank sheets of paper stacked horizontally with one vertical cut that almost reaches the top of the pages. Staple across the top of the cut pages. It should look like two strips consisting of multiple pages with a solid stapled bar of paper at the top. Write a selection of base words and prefixes on the board for the kids to select. Kids should write their selected prefixes on the left section of pages, and base words on the right section of pages. This allows them to flip through pages to see different options for combining prefixes and base words. See who can use their flip books to create the most words.
This is an activity that allows kids to create words with a partner. Write an assortment of prefixes and base words on sticky notes, making sure each one has a match, and place them all in a bag or basket. Good word examples would be im/patient, in/considerate, end/less and under/stand. There are many other word combinations that work as well. Have the kids choose a sticky note without looking and stick it to their shirt. Allow the kids to mingle until they find a partner with a prefix or base word that goes with theirs.