The Scientific Method and Forensic Science

Scientific Method Outline Develops into a theory Identify the problem Gather Background Research Formulate a Hypothesis Experiment Conclusion Communicate Results Accept Hypothesis Rejects Hypothesis Repeat Experiment (MANY times)

Hypothesis explain cause Attempts to _________ something. Must: Include a ________ and _________ Be able to be _______ Be written as a ______________ explain cause effect tested Is an attempt to explain something. Include a condition. Be able to be tested and falsified. Be written as a statement. statement

Which of the following would be considered a hypothesis? Hyperactivity is unrelated to eating sugar. If you get 6 hours of sleep, you will do better on tests. Apples taste better than oranges. Does eating too much sugar lead to weight gain? The truth about sugar is that sugar rots your teeth. Increased exposure to UV light increases the incidence of skin cancer.

The Walking Moai of Easter Island Create a hypothesis that explains how these giant statues “walked” Before you create a hypothesis, what background information do you need?

The “Walking” Moai of Easter Island Most of the statues weighed five tons Most statues have wider bases than shoulders According to legend the Moai “walked”

The Answer https://www.youtube.com/watch?v=J5YR0uqPAI8

Creating An Experiment Should only test _____________ variable Should include an __________ group and a _________ group One independent experimental You should only test one variable. You must include a control group and at least one experimental group. control

Continued Control group Is used to _________ against experimental groups. _________ get the treatment/variable Experimental group ____________ the treatment/variable compare Does not The control is used to compare against experimental groups. The control is not changed. Receives

Variables Independent variable: Variable that __________ The _________ E.x. Dependent variable: Variable that is ________ by the change The __________ is manipulated (or changes) cause The independent variable is the variable that changes. The dependent variable is the variable that is EFFECTED by the change. effected effect

Scooby Identify the following: What is your hypothesis? Observation: I always wash Scooby with Petsmart brand shampoo and notice he is losing his hair. Experiment: Wash Scooby with Pestsmart shampoo for two weeks. Switch to Purina dog shampoo for two weeks. Results: Scooby lost equal amounts of hair during the experiment. Identify the following: What is your hypothesis? Independent variable: Dependent Variable: The Control Group:

Data Analysis Look for a significant __________ in the experimental group(s) Compare the ________ group to the experimental group(s) difference control **The experimental group = the independent variable

What is a Significant difference? Determines how sure you are that a __________ exists The difference is unlikely due to __________ Indicates a ________ and _________ relationship chance The variable you changed caused the results you observed. cause effect

Formulating a Conclusion Must restate the _____________ Does the data _________ your hypothesis? Yes = _________________ No = __________________ hypothesis support Accept hypothesis You should restate the hypothesis. You should accept or reject the hypotheis based on your data. Discuss sources of error and how they impacted your results. Reject hypothesis

The Orchid I notice that my orchid plant is starting to die. I think that it may be getting too much sun. I leave the plant in its normal spot for two weeks and notice that 2 flowers have died. I move it a shady area of the room for two weeks and notice that none of the flowers died. Then I move it to a sunny window sill and notice that all of the flowers have died. What should your hypothesis be? Identify the control variable Identify the independent variable Identify the dependent variable

Rat Experiment Experimental Question: Does an all organic diet reduce the occurrence of cancer in rats?

Experimental Design Does the wavelength of light (R.O.Y.G.B.I.V.) affect a plant’s growth? Does Rogaine really improve hair growth? Is acid rain causing a decline of frog populations? Does the hormone estrogen increase the milk yield of dairy cows? Does the size of a fish tank determine how large a fish will grow? Does aspirin keep cut roses fresher longer? Will crickets chirp more if the temperature is warmer? Do wounds heal faster when they are covered by Band-Aids? Which battery lasts longer, energizer or duracell? Does hot water freeze faster than cold water?  Do tanning beds cause skin cancer? What causes leaves to fall in autumn (light, temperature, or both)?

Make an Observation about Snickers

Snickers (continued) What should you hypothesis be? Identify the control group Identify the independent variable Identify the dependent variable Set up an experiment to test your hypothesis You must include two experimental groups and a control group

Muscle Power Joker was told that a certain muscle cream was the newest best thing on the market and claims to double a person’s muscle power when used as part of a muscle-bulding workout. Interested in this product, he buys the special muscle cream and recruits Magneto and Loki to help him. Joker develops a weight-lifting program for Magneto and Loki. He meets with them once every day for a period of 2 weeks and keeps track of their results. Before each session Magneto’s arms and back are lathered in the muscle cream, while Loki’s arms and back are lathered with the regular lotion.

Muscle Power Continued Time Patrick’s Reps SpongeBob’s Reps Initial Amount 18 5 After 1 Week 24 9 After 2 Weeks 33 17

Bubbles Patrick and SpongeBob love to blow bubbles! Patrick found some Super Bubble Soap at Sail-Mart. The ads claim that Super Bubble Soap will produce bubbles that are twice as big as bubbles made with regular bubble soap. Patrick and SpongeBob made up two samples of bubble solution. One sample was made with 5 oz. of Super Bubble Soap and 5 oz. of water, while the other was made with the same amount of water and 5 oz. of regular bubble soap. Patrick and SpongeBob used their favorite bubble wands to blow 10 different bubbles and did their best to measure the diameter of each one. The results are shown in the chart.

Bubbles Continued

Microwaved Fish Food Thor believes that fish that eat food exposed to microwaves will become smarter and would be able to swim through a maze faster. He decides to perform an experiment by placing fish food in a microwave for 20 seconds. He has the fish swim through a maze and records the time it takes for each one to make it to the end. He feeds the microwaved food to 10 fish and gives regular food mixed with microwaved food to 10 others. After 1 week, he has the fish swim through the maze again and records the times for each fish.

Microwaved Fish Food Continued -6 -1 -15 -34 -7 +5 +5 -7 -7 -4 -5 +9 +15 -6 -2 -15 -9 -7 -17 -4

The Microscope