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8 th GRADE SCIENCE. STRAND 1 THE NATURE OF SCIENCE NS 1.8.1 – NS 1.8.3. THE SCIENTIFIC METHOD. The Scientific Method is a series of planned steps used by scientists to solve problems. These are the steps: 1. Ask a question or determine a problem. 2. Make a Hypothesis.
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8th GRADE SCIENCE STRAND 1 THE NATURE OF SCIENCE NS 1.8.1 – NS 1.8.3
THE SCIENTIFIC METHOD • The Scientific Method is a series of planned steps used by scientists to solve problems. These are the steps: • 1. Ask a question or determine a problem. • 2. Make a Hypothesis. • 3. Gather data and test your hypothesis. • 4. Analyze the results of your testing. • 5. Draw a conclusion.
BIGFOOT! • A Game and Fish officer in Little Rock received a phone call from a person in northwest Arkansas, claiming he had evidence of a “Bigfoot” sighting there. • The caller stated they had a plaster cast footprint, a sample of weird looking hair they found on a barbed wire fence, an actual picture of “Bigfoot”, and, they had an eye-witness.
BIGFOOT • Based on the data the officer gathered over the phone, he can make his HYPOTHESIS. • I THINK THERE IS A “BIGFOOT” IN NORTHWEST ARKANSAS. • Now what does the officer have to do? • Go up there and gather the evidence. THEN… • Test the evidence!
BIGFOOT • The officer gathered these 3 pieces of data. The eyewitness lived a few miles up in the hills, so he would save him for last. • He sent the picture to a photo lab to be analyzed. • He sent the hair sample to a lab to be analyzed. • He decided to “stake out” the area where the footprint was located.
BIGFOOT • He went to the area dressed in his camo, and hid in the bushes. • After several hours he heard a loud THUMP! • Then several seconds later another THUMP! Then another and another, it was getting closer. • The officer saw a man who had a long metal pole with a metal cut out of a huge foot on the end of it. The man was slamming the foot into the ground, making footprints.
BIGFOOT • The officer stepped out of the bushes and confronted him. • After questioning, the man finally confessed that he had a whiskey still hid in the area, and he thought that if people thought there was a bigfoot monster in the area, they would be scared and stay away so he could make his whiskey.
BIGFOOT • A day later, results from the hair sample and picture came back. • The hair sample was that of a north American black bear. • The picture was blown up 200 times, and a zipper could be seen in the back of it.
BIGFOOT • The officer still had his eye-witness to check out. He drove 3 miles up the old dirt road to talk to the man.
BIGFOOT • His dogs met him at the door!
BIGFOOT • When the man came out, he was drunk as a skunk, and told him he had seen bigfoot, pink elephants, and flying saucers too!
BIGFOOT • What at first seemed liked a good hypothesis, turned out to be false, but ONLY after testing the evidence. • He now had to make his conclusion…. • THERE IS NOT A BIGFOOT IN NORTHWEST ARKANSAS!
VOCABULARY • 1. CONTROL – In an experiment, the standard for comparison. • 2. VARIABLE – Measurable factor, characteristic, or attribute of an individual or a system. • 3. EMPIRICAL EVIDENCE – Data that can be detected, observed, or measured. • 4. HYPOTHESIS – An “educated guess”. An explanation for a question or a problem that can be formally tested. • 5. THEORY – A hypothesis that has been tested many, many times by different scientists, and the results turn out the same.
VOCABULARY • 6. SCIENTIFIC LAW - A descriptive generalization about how some aspect of the natural world behaves. A theory that has been tested over and over by many scientists, and is considered a “fact” of nature. • 7. EXPERIMENTAL DESIGN – The design of a suitable experiment to test a hypothesis. • 8. DEPENDENT VARIABLE – Factor being measured in an experiment, found on the vertical or Y-axis on a graph. • 9. INDEPENDENT VARIABLE – The one factor changed in an experiment, represented on the horizontal or X-axis on a graph.
VOCABULARY • 10. SCIENTIFIC METHOD – A series of problem solving procedures used by scientists.
EXPERIMENTS • Coach Bales thinks he has come up with a “SUPER DUPER GROWTH PILL” • His HYPOTHESIS (educated guess) is “I believe my super duper growth pill will increase the size of a rat over a period of time” • His empirical evidence will be: • 2 rats from the same litter, as close in size and weight as he can get. • Each rat will get the same kind of food and water, also in same amounts. • 1 rat will be given the “SUPER DUPER GROWTH PILL”
GROWTH PILL EXPERIMENT • Rat 1 • This rat will not be given the pill. • He will be the CONTROL, the standard for comparison in the experiment.
GROWTH PILL EXPERIMENT • Rat 2 • Rat 2 will get the SUPER DUPER GROWTH PILL! • This will be the VARIABLE, or the changeable factor of the experiment. • It is very important in an experiment that you only test one variable at a time.
GROWTH PILL EXPERIMENT • Coach Bales will give each rat the same amount of food and water at the same time each day. • Only rat 2 will get the growth pill. • He will be compared to rat one to see if he grows more or not. • After 2 weeks……..
GROWTH PILL EXPERIMENT • Based on the evidence that the rat given the growth pill did in fact get bigger in size, Coach Bales can now form a theory, a hypothesis that has been tested. • His theory though, must be tested many more times by many different scientists before it can be accepted as a “scientific law” or a fact of nature.
