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

Hypothesis Writing

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

Key Info

Hypothesis

 "If I open the faucet [faucet opening size is the independent variable], then it will increase the flow of water [flow of water is the dependent variable]. EXAMPLES

 "If I put fenders on a bicycle [having fenders is the independent variable], then they will keep the rider dry when riding through puddles [the dependent variable is how much water splashes on the rider]." 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. EXAMPLES

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

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

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

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

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.

What is a variable?  A variable is something that can change, either naturally or on purpose. ***  In an experiment it is a factor that is different from one group to another.  Independent variable  The factor that the scientist has changed in order to test the hypothesis (on purpose). It is the cause  Dependent Variable  The result of what the scientist changed. It is the effect of what happened in the experiment.

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

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

CHECKLIST What makes a good hypothesis?For a good hypothesis, you have a checkmark in each box. Is the hypothesis based on information contained in the Research Paper? Does the hypothesis include the independent and dependent variables? Have you worded the hypothesis so that it can be tested in the experiment?

 WRITE DETAILED INSTRUCTIONS FOR MAKING A PEANUT BUTTER AND JELLY SANDWICH.  USE LIST FORM LIKE A PROCEDURE. See that’s not so bad! HOMEWORK!