Write down possible ways to solve the mystery…..how do I make a peanut butter and jelly sandwich?

The Scientific Method Model, guide, or technique used to solve problems and to get information

Problem Hypothesis Experiment Results Conclusion Repeat Purple Hippos Eat Really Cold Raviolis

6 STEPS Always in the form of a question What you want to solve 1. State a Problem

Problem Under what color light will plants grow best?

2. Form a Hypothesis EDUCATED GUESS Suggested answer to the problem Based on prior knowledge

Hypothesis I think the plant under green light will grow best because plants are green.

State one possible hypothesis for this experiment.

DO NOW: List the steps of the scientific method

3. Perform a Experiment TEST IF HYPOTHESIS IS RIGHT OR WRONG Gather materials Design procedures

Experiment Grow the plants for 5 weeks. Each is placed under a certain color light. They will get the same amount of light, & will be watered every 2 days. Their height will be measured (in centimeters) once a week.

4. Record your RESULTS Writing down all data/observations that are made during the experiment How? Graphs, charts…

Height (cm) PLANTS Observations Growth of plants

5. State a Conclusion Answers the question stated in the problem States if the hypothesis is right or wrong? Explains data A conclusion is a multi-sentence statement that:

Conclusion My hypothesis was wrong. Plants grow best under blue light, not green light. The plant under blue light grew 11cm while the plant under green light grew only 2 cm.

6.Repeat the experiment The entire experiment must be done again to be valid. Valid – proven to be logically true; to be proven legitimate To find any errors

Final Summary 1.Name the steps of the scientific method. 2.Define the term hypothesis 3.A possible explanation for an observed set of facts is called a a.)variable b.) control c.) hypothesis d.) theory

A Controlled Experiment contains two groups: Experimental Group and the Control Group All experiments are designed to be controlled

the group that is used for comparison and does not contain the independent variable 2. Control group

the group of subjects that are being tested on. This group does receive the INDEPENDENT VARIABLE 2. EXPERIMENTAL GROUP

Variable Any factor(s) in an experiment There are 3 1.Independent 2.Dependent 3.Constant

The factor that is purposely altered by the scientist, that may (or may not) lead to change in the dependent variable. Generally it is the factor that you are testing. 1. Independent Variable

Independent variable = ? SUNLIGHT

What is the variable is this experiment? The color of the light

The factor that is being measured to see if the independent variable caused a change. 2. Dependent Variable

Dependent Variable? Growth of plant

The variable or factor that stays the same in both the Experimental And the Control groups -soil -pot -plant 3. Constant

Everything between the 2 groups must be exactly the same except for the independent variable!!!

Identify 2 conditions, other than the size of the container and the amount of soil, that should be held constant in this experiemtn. 1.____________ 2.____________

What must be done to make results of an experiment more reliable or valid? Repeat experiment Use a larger subject/sample size Use only one variable

What is a THEORY? A hypothesis supported by many experiments Thought to be true but can be changed

What is a LAW? A statement that is believed to be true

What is the independent variable? Substance Z What is the dependent variable?height Ex # 2: To investigate the effect of a substance on plant growth, 2 bean plants of the same species were grown under identical conditions with Substance Z added to the soil of one of the plants. At the end of 2 weeks, the plant grown with Substance Z was 12.5 cm tall. The plant grown without Substance Z was 12.2cm tall. The researcher concluded that the presence of Substance Z causes the plants to grow taller. Which setup is the control? Plant without Substance Z

Example #3 How bright is right? An automobile manufacturer wants to know how bright brake lights should be in order to minimize the time required for the driver of a following car to realize that the car in front is stopping and to hit the brakes. What is the independent variable? brightness of brake light What is the dependent variable? time to hit brake

What is the independent variable? Water What is the dependent variable? growth Ex #4: A student placed 5 geranium plants of equal size in 5 environmental chambers. Growing conditions were the same for each plant except for the amount of water each received. At the end of 20 days, plant growth was measured.

5. An investigation was designed to determine the effect of ultraviolet light on mold spore growth. Two groups of mold spores were grown under identical conditions, except one group was exposed only to ultraviolet light, while the other group was grown in total darkness. In this investigation, the group of mold spores grown without receiving any ultraviolet light is known as the a. experimental variable b. hypothesis c. control d. limiting factor

6. Which sentence represents a hypothesis? a. Environmental conditions affect germination. b. Boil 100 milliliters of water, let it cool, and then add 10 seeds to the water. c. Is water depth in a lake related to available light in the water? d. A lamp, two beakers, and elodea plants are selected for the investigation.

EX #1: Does beta-carotene protect against cancer?beta-carotene Beta-carotene supplements have been thought to protect against cancer. But one study suggests this is false. The study was conducted with 39,000 women aged 45 and up. These women were randomly assigned to receive a beta-carotene supplement or a placebo. Their health was studied over their lifetime. Cancer rates for women taking the beta-carotene supplement did not really differ from the cancer rates of those women taking the placebo.placebo What is the independent variable? supplements: beta-carotene What is the dependent variable? How many patients got cancer

How do scientist create experiments?