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

TheScientifi

cMethod

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

ProblemUnder what color light will

plants grow best?

2. Form a Hypothesis

EDUCATED GUESSSuggested 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 aExperiment

TEST IF HYPOTHESIS IS RIGHT OR

WRONGGather materialsDesign

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…

2

4

6

8

10

12

Heig

ht

(cm

)

PLANTS

1 2 3 4 5 6

Observations Growth of

plants

5. State aConclusion

• 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.Repeatthe 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 hypothesis3. 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

comparisonand 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 31.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 anexperiment

more reliable

or valid?

•Repeat experiment•Use a larger subject/sample size

•Use only one variable

What is aTHEORY?

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 ZWhat 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 #3How 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 lightWhat is the dependent variable?time to hit brake

What is the independent variable?WaterWhat 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 variableb. hypothesisc. controld. 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 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.

What is the independent variable?supplements: beta-caroteneWhat is the dependent variable?How many patients got cancer

How do scientist create How do scientist create experiments?experiments?