Creating a Hypothesis

1. Creating a Hypothesis What do you predict will happen when you do your experiment?!

2. It does not matter that your experiment has been done a thousand times before! • What matters is that you don't know the results and that you can independently find a verifiable answer. Real hypotheses should be written before the experiment! What does verifiable mean?

3. It does not matter that your experiment has been done a thousand times before! • What matters is that you don't know the results and that you can independently find a verifiable answer. Real hypotheses should be written before the experiment! Verifiable: capable of being tested (verified or falsified) by experiment or observation.

4. A hypothesis is a statement that proposes a possible explanation to some phenomenon or event. • A useful hypothesis is a testable statement which may include a prediction. • If … then … The key word is testable! Real hypotheses should be written before the experiment!

5. You will perform a test of how two variables might be related. • This is when you are doing a realexperiment. • You are testing variables. Testing a Hypothesis

6. Usually, a hypothesis is based on some previous observation • For example: • In November many trees undergo color changes in their leaves ANDthe average daily temperatures are dropping. • Are these two events connected?How? Previous Observations

7. Chocolate may cause pimples. • Salt in soil may affect plant growth. • Plant growth may be affected by the color of the light. • Bacterial growth may be affected by temperature. • Ultra violet light may cause skin cancer. • Temperature may cause leaves to change color. Do you think that these statements make good hypotheses? How are hypotheses written?

8. Chocolate may cause pimples. • Salt in soil may affect plant growth. • Plant growth may be affected by the color of the light. • Bacterial growth may be affected by temperature. • Ultra violet light may cause skin cancer. • Temperature may cause leaves to change color. We need to create If… then… statements. The word MAY does not suggest how we would prove these statements.

9. Original: • Ultra violet light may cause skin cancer. If… then… • Ifskin cancer is related to ultraviolet light , then people with a high exposure to UV light will have a higher frequency of skin cancerbecause… Original: • Temperature may cause leaves to change color. If… then… • Ifleaf color change is related to temperature , then exposing plants to low temperatures will result in changes in leaf color because… If… then… statements

10. If… then… • Ifskin cancer is related to ultraviolet light , then people with a high exposure to UV light will have a higher frequency of skin cancerbecause… If… then… • If leaf color change is related to temperature , then exposing plants to low temperatures will result in changes in leaf color because… Variables DEPENDENT VARIABLE INDEPENDENT VARIABLE

11. If… then… • Ifskin cancer is related to ultraviolet light , then people with a high exposure to UV light will have a higher frequency of skin cancer. If… then… • If leaf color change is related to temperature , then exposing plants to low temperatures will result in changes in leaf color. DEPENDENT VARIABLE The variable that you observe and measure the results INDEPENDENT VARIABLE The variable that you control and change. Variables

12. Chocolate may cause pimples. • Salt in soil may affect plant growth. • Plant growth may be affected by the color of the light. • Bacterial growth may be affected by temperature. Rewrite the first four hypotheses as If… then… statements. Single underline the dependent variable and double underline the independent variable. Practice

13. Write the hypothesis for your experiment as an If… then… statement using the worksheet. Be sure to identify the dependent variable and the independent variable. Your hypothesis