Forming a Hypothesis Hypothesis: an educated guess or prediction; an “if, then, because” statement If ____independent variable______ then __dependent variable_______, because _____logical reason why_______

Example: Independent Variable: I feed my cat a lot of food Dependent Variable she will get fat If ______________________ then ____________________ because __________________

Try to use INCREASE and DECREASE in your hypothesis! Remember Try to use INCREASE and DECREASE in your hypothesis! Ex. IF I increase the amount of food I give my cat, THEN she will increase her weight

Types of Variables There are 3 main types of variables: Independent Variable: The variable that is changed by the scientist; the ‘I control’ variable Dependent Variable: The variable that might change because of what the scientist changes – what is being measured Control Variable: something that scientist makes sure is the same throughout the experiment

Remember! Your hypothesis can TELL you what your variables are! Ex. If I drink Mountain Dew before bed, then I will not sleep very much, because Mountain Dew contains so much caffeine. IV: Drinking Mountain Dew DV: the amount of sleep

Use this hypothesis to identify the variables: Practice Use this hypothesis to identify the variables: If I leave all the lights on all day then my electric bill will be expensive, because I am charged by the amount of time I use electricity. IV: ______________________ DV: ______________________

If I brush my cat more then there will be less fur on my furniture, because the cat won’t have the fur on him to shed off. IV: ______________________ DV: ______________________

Now read the following experiment and identify the independent and dependent variables Elizabeth wanted to test if temperature affected how fast milk goes bad and curdles. She left milk in a room temperature closet, a fridge, and a oven that was turned on low heat. She then measured how rotten the milk was after 10 days. IV: ____________________________________ DV: ____________________________________

Review In an experiment, there is something that a scientist is testing – they control this…

Review In an experiment, because the scientist is changing this independent variable, this is going to change and the scientist will measure that change…

Review This is an educated guess of what is going to happen during an experiment – the scientist forms this at the beginning of the experiment….