Hypotheses are not just random guesses, but predictions about the outcome of an experiment. If you change variables a, b or c, then x,y or z may change. Students can practice making hypotheses with this formula in mind. Give students a pile of paperclips and different strengths of magnets. Observe if the strength of a magnet changes the number of paperclips picked up by the magnet. Instruct students to fill in the blanks of this statement, "If the strength of the magnet (increases or decreases), then the number of paperclips picked up (increases or decreases)." This is making a hypothesis. Continue testing the hypothesis through experimentation by changing the magnets and recording the number of paperclips gathered by each.
In this experiment, students can test the reaction of baking soda, vinegar and a balloon when the substances combine.
Place vinegar in a empty water bottle and baking soda in a balloon. Students place the filled balloon on the bottle, and when the vinegar and baking soda mix, the balloon inflates with carbon dioxide gas. Students can make a hypothesis based on the amount of baking soda placed in the balloon. A sample hypothesis is, "If the amount of baking soda is increased, the size of the balloon will increase."
Viscosity measures how an element flows. By combining various types of glue and Borax to create slime, students can make a hypothesis about whether the viscosity of the slime changes when the glue variable changes. A student's hypothesis may be, "If we use glue with a slow viscosity, the viscosity of the slime will be slow as well."
This experiment tests the types of citric juices used to prevent the browning of apples. A student's hypothesis could be, "Some citric juices will not prevent apples from browning." Some may guess yes, others no. Make sure that the tests are controlled, meaning that all apple slices must be the same size, the sample of citric juices must be the same amount and coverage of the apples must be the same. Once the experiment is complete, students will see the result of their hypothesis.