Hypothesis Writing

1. 59. Animal cells contain an enzyme that breaks down hydrogen peroxide. Gas is released when hydrogen peroxide is broken down. A scientist used a pipette to drop hydrogen peroxide onto a sample of muscle tissue. Bubbles formed on the tissue. The scientist concluded that the enzyme was present in the muscle tissue. Which type of observation led the scientist to form this conclusion? A. Qualitative observation of the amount of enzyme present in the tissue B. Qualitative observation of the bubbles formed from enzyme activity C. Quantitative observation of how much gas formed in the bubbles D. Quantitative observation of the amount of enzyme present in

2. Hypothesis Writing No it’s not JUST an educated guess! 

3. What is a hypothesis? • An explanation that is based on prior scientific research or observations and that can be tested. • “EducatedGuess ( your high school teacher may not like this definition) • “If… then… because” Statement

4. Key Info After having thoroughly RESEARCHED your question, you should have some educated guess about how things work. Most of the time a hypothesis is written like this: "If _____[I do this] _____, then _____[this]_____ will happen." (Fill in the blanks with the appropriate information from your own experiment.) Your hypothesis should be something that you can actually test, what's called a testable hypothesis. In other words, you need to be able to measure both "what you do" and "what will happen."

5. EXAMPLES If a plant receives fertilizer independent variable, then it will grow to be bigger than a plant that does not receive fertilizer dependent variable.

6. EXAMPLES "Raising the temperature of a cup of water independent variablewill increase the amount of sugar that dissolves dependent variable."

7. Practice Part 1 Identify the independent variable in each of following hypotheses: 1. Warmer temperatures decrease the hatching times for robin eggs. 2. Crickets chirp more when they get more food. 3. Dogs howl more when the moon is full. Answers: 1. temperature-you change the temperature in each test 2. amount of food-you change the amount of food in each test 3. amount of moonlight-you change the amount of moonlight in each test

8. Practice Part 2 Identify the dependent variable in each of following hypotheses: 1. Warmer temperatures decrease the hatching times for robin eggs. 2. Crickets chirp more when they get more food. 3. Dogs howl more when the moon is full. Answers: 1. hatching time-it depends on the temperature 2. amount of chirping-it depends on the food 3. amount of howling-it depends on the amount of moonlight

9. How do you test a hypothesis? • Develop a test to support or not support your hypothesis. • Must be run multiple times • Must have only 1 independent variable (the factor being tested • Must include 2 groups • Experimental group • Control group

10. How do you test a hypothesis? • Use a Controlled Experiment • An experiment that tests only one factor at a time by using a comparison of a control group and an experimental group. • The Control Group that the scientist changes nothing in. The Control group is used for comparison. • The Experimental Group that the scientist has changed something. It is the variable in the experiment where you want to see how this condition affects something.

11. What are constants or control variables? • They are what the scientist kept the same in both the control group and the experimental group.

12. How can you gather data? • Make Observations. • Any use of the senses to gather information. • Qualitative Observations • Anything that you see, smell, touch, taste, or hear. • Ex. Blue, bitter, fizzing sound. • Quantitative Observations • Any observation that can be measured. • Must include a number. • Ex. 5 centimeters long