Give each student a paper plate, half of an apple, grapes and raisins. Have your students make a happy face on their apple using the fruit. Tell them that they can use the grapes and raisins to make the eyes nose and mouth of the happy face apple. Next give your students another apple half, grapes and raisins and ask them to make a sad face apple this time.
When the students have completed both faces, have them raise their hands. Then give each student half of a lemon that you have already gently squeezed a few times to help release the juice. Ask the students to squeeze the lemon juice on the happy face apple only, not on the sad face. Remind the students that they should keep the lemon juice away from their eyes.
Talk to the students about their happy and sad face apples and have them discuss which fruit they used for the eyes, nose and mouth. Then have them wash their hands and sit on the rug for reading time. Read the Dr. Suess book, "Five Apples Up on Top" and discuss the book with the students. Discuss how the students made their apple faces and which ones they put the lemon juice on. This will provide about 15 minutes' wait for the ascorbic acid to work.
Discuss how the students made their apple faces and which face they put the lemon juice on. Then excuse the students to go back to their desk. Ask them if there have been any changes to their happy or sad faces. Have the students discuss the changes they observed on their happy and sad face apples faces.
Write the word "oxidation" on the whiteboard. Tell your students that oxidation is caused by oxygen. Let them know that oxidation can affect fruit by turning it a brownish color. Ask which apple face was affected by oxidation. Ask the students if they have seen oxidation before on fruit at home or at school.
Write the word "ascorbic acid" on the whiteboard. Explain that the lemon juice contains ascorbic acid which protects fruit from oxidation. Then let your students eat the happy face apple. Ask the students how the lemon changes the taste of the apple.