1. THE SCIENTIFIC METHOD

2. Types of variables: 2. dependent variable: 1.independent variable: Variable that is changed in an experiment. What is being investigated

3. A student wishes to study the effect of plant food on the growth of spider plants. She designs an experiment with three setups. Each setup contains five healthy spider plants grown in potting soil. All plants receive the same amount of sunlight and water. 1 gram of plant food is added to each plant in setup one. 3 grams of plant food is added to each plant in setup two. The third setup receives no plant food. After one month, she measures the height of the plants. Independent variable?Amount of plant food

4. Types of variables: 2. dependent variable: 1.independent variable: Variable being measured in an experiment.

5. A student wishes to study the effect of plant food on the growth of spider plants. She designs an experiment with three setups. Each setup contains five healthy spider plants grown in potting soil. All plants receive the same amount of sunlight and water. 1 gram of plant food is added to each plant in setup one. 3 grams of plant food is added to each plant in setup two. The third setup receives no plant food. After one month, she measures the height of the plants. Dependent variable?Height of the plants

6. Constants: those variables that are kept the same

7. A student wishes to study the effect of plant food on the growth of spider plants. She designs an experiment with three setups. Each setup contains five healthy spider plants grown in potting soil. All plants receive the same amount of sunlight and water. 1 gram of plant food is added to each plant in setup one. 3 grams of plant food is added to each plant in setup two. The third setup receives no plant food. After one month, she measures the height of the plants. Constants?Amount of sunlight and water

8. item or group that does not receive experimental treatment Control:

9. A student wishes to study the effect of plant food on the growth of spider plants. She designs an experiment with three setups. Each setup contains five healthy spider plants grown in potting soil. All plants receive the same amount of sunlight and water. 1 gram of plant food is added to each plant in setup one. 3 grams of plant food is added to each plant in setup two. The third setup receives no plant food. After one month, she measures the height of the plants. Control?Plants that received no plant food

10. Two groups of 50 rats are tested in a lab. Both groups are kept in a 5 x 5 x 2 ft cage in a temperature controlled room (25° C). Both groups are provided with water and fed 125 grams of food daily. Group 1 is given a growth hormone. Group 2 does not receive any growth hormone. At the end of six months, the rats are weighted. Independent variable?Growth hormone

11. Two groups of 50 rats are tested in a lab. Both groups are kept in a 5 x 5 x 2 ft cage in a temperature controlled room (25° C). Both groups are provided with water and fed 125 grams of food daily. Group 1 is given a growth hormone. Group 2 does not receive any growth hormone. At the end of six months, the rats are weighted. Dependent variable?Weight of the rats

12. Two groups of 50 rats are tested in a lab. Both groups are kept in a 5 x 5 x 2 ft cage in a temperature controlled room (25° C). Both groups are provided with water and fed 125 grams of food daily. Group 1 is given a growth hormone. Group 2 does not receive any growth hormone. At the end of six months, the rats are weighted. Constants?Cage, temp, water, and food

13. Two groups of 50 rats are tested in a lab. Both groups are kept in a 5 x 5 x 2 ft cage in a temperature controlled room (25° C). Both groups are provided with water and fed 125 grams of food daily. Group 1 is given a growth hormone. Group 2 does not receive any growth hormone. At the end of six months, the rats are weighted. Control? Rats not receiving growth hormone

14. Dependent var? You know soda promotes tooth decay, but you want to know if all sodas have the same effect. You get 5 models of teeth and place them different sodas after weighing them. You get a 6 th model and place it in water. You keep all of the models in the same room at room temperature. After 2 months, you measure the mass of the models. Independent var? Constant? Control? Mass of the model teeth Different types of soda Model teeth, amount of soda, temp, time water