What is the difference between a dependent and an independent variable?

Independent Variable (IV)  “I change”  What you purposely change in the experiment.

Dependent Variable (DV)  What changes because you changed the independent variable

Controlled Variable (CV)  What stays the same in the experiment.

 Nancy wanted to see if sugar would dissolve quicker in hot or cold water. IV (Independent Variable): DV (Dependent Variable): CV (Controlled Variable):

 A scientist has two rabbits that weigh the same amount. The rabbits are placed in separate identical cages. Both rabbits drink the same amount of water each day. The first rabbit is given 16 grams of Topnotch Rabbit Food each day. The second rabbit is given 16 grams of Superior Rabbit Food each day. At the end of two weeks, the rabbits are weighed. The first rabbit weighs more than the second rabbit.  IV  DV  CV

 In order to learn the effect of light on plant growth, students want to place one plant in darkness and another in sunlight. They plan to measure the height of the plants each day.  IV  DV  CV

 Sara investigated the rate salt dissolved in different temperatures of water. She filled two beakers with of water each. The water was in one beaker and in the other. She added of salt to each beaker.  IV  DV  CV

 A student did an experiment to determine what paper towel will absorb water better.  IV  DV  CV

 Tonya wants to know what kind of seeds the birds in her area eat the most. She places three identical containers on a tray outside. Tonya puts the same amount of corn in one container, sunflower seeds in the second container, and a mixture of seeds in the third. She plans on checking the investigation twice a day for a week.  IV  DV  CV

 Claudia investigates on which type of surface her skateboard will travel the farthest. She pushes her skateboard with the same amount of force on a sidewalk, grass, and street. Claudia records the results and compares the distances the skateboard traveled.  IV  DV  CV

 Juan finished a jug of milk and placed the lid back on the jug. Later he heard a “pop” and saw the lid on the floor. He decided to conduct an investigation using different empty containers with lids to see how long it takes for the lids to pop off.  IV  DV  CV

 Emma wanted to know if a new kind of container would keep seeds warmer than other containers. She placed the same amount of soil and the same number of bean seeds in both kinds of containers. Emma placed a thermometer in the soil in each container.  IV  DV  CV

 Marta and Roger are comparing how long it takes two different types of seeds to sprout. They plant both types of seeds in similar pots, place them in a sunny window, and water them daily.  IV  DV  CV