Warm-up: 8 minutes Just write your answers in complete

sentences. You may use your notes. There is no talking.

1. Dr. Cao was walking in the park one day when she sees a dog with three legs.

a) What is the observation that she made?

b) What inference can be made?

2. What is the formula for density?

3. M = 2000 g, V = 10 ml. What is density?

Don’t forget the units!

The Scientific Method

The Scientific Method

• An organized way to solve a problem through experimentation & observation.

• This is the basis of science!

The 6 Steps of the Scientific Method

1. State the Problem

• Form a question or observation about a specific event

Example: Mouthwash kills bacteria. Which brand works best?

2. Form a hypothesis and predictions

• A hypothesis is an educated guess that explains your observation or problem.

• You will then form predictions, which are expectations based on your hypothesis.

Example: IF Listerine has more antiseptic ingredients than Crest or the Wal-Mart brand, THEN it will kill more bacteria.

2. Form a hypothesis and predictions

Example Hypothesis: Name brand mouthwash works better than store brand.

Example Predictions: If name brand mouthwash works better, then Listerine should kill more mouth bacteria than the Wal-mart brand

3. Design an Experiment

• Create a way to test your hypothesis.

Create a CONTROLLED experiment.

• A controlled experiment MUST have 2 groups.

CONTROL GROUP: all conditions remain the SAME! It is a group you do not do anything to.

EXPERIMENTAL GROUP: a group or many groups who you test.

The experiment is performed on this group.

• Establish the variables for your experiment.

INDEPENDENT VARIABLE: the variable that you change or manipulate (X axis for graphing)

DEPENDENT VARIABLE: the change or result that happens when the independent variable is used (Y axis for graphing)

• Establish the variables for your experiment.

INDEPENDENT VARIABLE: the variable that you change or manipulate (X axis for graphing)

DEPENDENT VARIABLE: the change or result that happens when the independent variable is used (Y axis for graphing)

4. Conduct your experiment and collect data

Mouthwash Experiment

Petri dishBacteria grown from swab

Control Group -no mouthwash

Experimental Group

Listerine

Crest Brand

Wal-Mart brand

Mouthwash Experiment

INDEPENDENT VARIABLE:

DEPENDENT VARIABLE:

Type of Mouthwash

Amount of bacteria killed

Recording data

Mouthwash brand

Listerine Wal-mart brand

Control- no mouthwash

Number of bacteria

5. Analyze Data

• Describe your data

• 2 Types of Data

QUANTITATIVE: numerical data, deals with specific quantities, usually in the form of a graph or chart

QUALITATIVE: descriptive data, describes how something looks, smells, sounds, or feels; deals with qualities

QUALITATIVE EX: The control group and the Wal-Mart brand have a strong smell; the Listerine & Scope don’t smell as bad.

QUANITATIVE EX: Area of Inhibition for Mouthwash Brands

Control Listerine Scope Wal-Mart

5 min 0 mm 3 mm 2 mm 1 mm

10 min 0 mm 4 mm 3 mm 3 mm

15 min 0 mm 6 mm 5 mm 4 mm

20 min 0 mm 8 mm 6 mm 4 mm

6. Form Conclusions

• Determine from the data collected if the hypothesis was correct or incorrect

• Do this by comparing results to predictions

• EX: You predicted Listerine would kill more bacteria than Wal-mart. But your data show that both Listerine and Wal-mart brand killed the same amount of bacteria. Was your hypothesis supported?

Your hypothesis was that brand name mouthwash was more effective at killing bacteria than Wal-mart brand.

Let’s Practice

• Who has a problem that they think science can help us solve?

Exit Ticket• I have 2 pairs of shoes and I am

not sure which pair of shoes will make me run faster.

• How do I find out? What should I do?

• Use the 6 steps of the Scientific Method in your answer.

Class Experiment• You will be designing an experiment to help you to better

understand the scientific method.

• Break up into groups (of 2-3 members) and design an experiment to investigate any testable hypothesis.

• Choose only one variable to manipulate.

• You will must work through all of the steps of the scientific method: – ask a question – develop a hypothesis and predictions– design your experiment (list materials that you will

use, and outline your procedure in detail, determine what data you will collect)

– pretend that you conducted your experiment and collected data

– analyze your data– form a conclusion (was your hypothesis supported or

not? Compare your results to predictions.).