Students bring in apples. Start with two students apples. Have students predict by looking at the apples which one might be the heaviest.
Place apples on balance.
Each student looks at his apple and predicts whether or not it might be heavier than the one on the balance. Allow each student to come up and compare by placing their apple on the balance. Continue until all apples have been compared and you find just one to be the heaviest. Understands the need for a uniform unit of measure to communicate in real-world situations. Now it is Fraction time and another standard can be taught.