The Scientific Method and Forensic Science Scientific Method

The Scientific Method and Forensic Science

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

Hypothesis • Attempts to _____ explain something. Must: cause 1. Include a ____ and _____ effect tested 2. Be able to be _______ 3. Be written as a statement _______

Which of the following would be considered a hypothesis? 1. Hyperactivity is 2. 3. unrelated to eating sugar. If you get 6 hours of sleep, you will do better on tests. Apples taste better than oranges. 4. Does eating too 5. 6. 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=J 5 YR 0 uq. PAI 8

Creating An Experiment • Should only test _______ One independent variable • Should include an experimental group and a _____ control group _____

Continued Control group • Is used to _____ compare against experimental groups. Does not get the • _____ treatment/variable Experimental group Receives • ______ the treatment/variable

Variables Independent variable: manipulated (or changes) • Variable that is _____ • The _____ cause • E. x. Dependent variable: effected • Variable that is ____ by the change effect • The _____ • E. x.

Scooby • 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: a) What is your hypothesis? b) Independent variable: c) Dependent Variable: d) The Control Group:

Data Analysis • Look for a SIGNIFICANT difference in the _____ experimental group(s) • Compare the ____ control group to the experimental group(s) **The experimental group = the independent variable

What is a Significant difference? • Determines how sure you are that a relationship exists _____ • The difference is • unlikely due to chance _____ Indicates a cause ____ and effect _____

Formulating a Conclusion • Must restate the hypothesis _______ support • Does the data _____ your hypothesis? § Yes = _________ Accept hypothesis Reject hypothesis § No = _________

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. a) What should your hypothesis be? b) Identify the control variable c) Identify the independent variable d) Identify the dependent variable

Rat 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) a) 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 b) c) d) e) • 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 weightlifting 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 Initial Amount Patrick’s Reps 18 Sponge. Bob’s Reps 5 After 1 Week 24 9 After 2 Weeks 33 17

Bubbles • Patrick and Sponge. Bob 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 Sponge. Bob 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 Sponge. Bob 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 -34 -7 +5 -7 -5 +15 -2 -9 -17 -1 -15 +5 -7 -4 +9 -6 -15 -7 -4

The Microscope