SCIENTIFIC METHOD

John watches his grandmother bakes bread. He asks his grandmother what makes the bread rise. She explains that yeast releases a gas as it feeds on sugar. Her grandmother uses 20g of sugar whenever she bakes. John wonders if the amount of sugar used in the recipe will affect the size of the bread loaf.

Hypothesis: If the amount of sugar is changed then the size of bread loaf changes also. MV/IV: Amount of Sugar DV: Size of bread loaf Constants: Recipe, ingredients, type of oven, temperature, time of baking, kind of pan Control: 20g of sugar

A zoologist wants to know if feeding mice a vitamin supplement will make them grow larger. She feeds five mice their regular food and she feeds five other mice food with vitamins. She measures the weight of the mice at the start and end of the experiment.

Hypothesis: If the mice are given vitamin supplement then they will grow larger/bigger. MV/IV: Vitamin Supplement DV: Growth of mice/Weight of mice Constants: Kind of mice, number of mice, kind & amount of food, size and weight of mice, number of feeding days, time of feeding, measuring device Control: regular food

A student is interested in the effect of the temperature of water in her aquarium on the activity level of her fish. She divides her aquarium water and fish into three aquariums, one that is maintained at room temperature (about 21 ⁰ C), one that is heated to 27 ⁰ C, and one that is cooled to 16 ⁰ C. At six p.m. each day, she watched the fish for 30 minutes and records her observation about their activity.

Hypothesis: If the temperature of the water is changed, then the level activity of the fish is affected. MV/IV: Temperature of water DV: Activity level of fish Constants: number of fish, type/size/ weight of fish, size of aquarium, level of water, time of observation, length of time of observation, number of days Control: Room temperature at 21 ⁰ C