The Scientific Method Making a Good Experiment

The Scientific Method Is the driving force for all scientific progression. Is the driving force for all scientific progression. Is based on gathering evidence through an experiment and drawing a conclusion from that evidence. Is based on gathering evidence through an experiment and drawing a conclusion from that evidence.

Remember The scientific method does not strive to prove what is true. The scientific method does not strive to prove what is true. It is used to disprove what is false/impossible It is used to disprove what is false/impossible This is why we deal with Theories in science, because we can never know with 100% certainty, if our findings are correct. This is why we deal with Theories in science, because we can never know with 100% certainty, if our findings are correct.

Remember No matter how much evidence you have, or certain of the truth you might be, you can never be 100% certain. No matter how much evidence you have, or certain of the truth you might be, you can never be 100% certain. Misinformed in the past: Misinformed in the past: Four element theory. Four element theory. Earth being flat. Earth being flat. Pleasant scents fighting sickness. Pleasant scents fighting sickness.

Where it Begins It all starts with a Question. What do you really want to find out? It all starts with a Question. What do you really want to find out? I want to find out what kind of liquid carrots will grow best in. I want to find out what kind of liquid carrots will grow best in. I want to know whether a 2L bottle of pop will go flat faster if I do not squeeze the bottle before sealing it. I want to know whether a 2L bottle of pop will go flat faster if I do not squeeze the bottle before sealing it.

Background Research It is important to look into what has already been discovered in this area before you start an experiment. It is important to look into what has already been discovered in this area before you start an experiment. Research the topic of your experiment and educate yourself before you begin. Research the topic of your experiment and educate yourself before you begin.

The Hypothesis A prediction about the results of the experiment before you run it. A prediction about the results of the experiment before you run it. Stated in an “if ______ then ______” format Stated in an “if ______ then ______” format IF carrots are given a food source with more nutrients, such as apple juice or orange juice, THEN they will grow faster/stronger. IF carrots are given a food source with more nutrients, such as apple juice or orange juice, THEN they will grow faster/stronger. Note: it is okay for a hypothesis to be wrong** Note: it is okay for a hypothesis to be wrong**

The Experiment Hypothesis Hypothesis Materials – all materials used in the experiment Materials – all materials used in the experiment Procedure – a step by step set of instructions, written in past tense. Exact numbers/amounts should be used. Procedure – a step by step set of instructions, written in past tense. Exact numbers/amounts should be used. Observations – what you observed Observations – what you observed Conclusions – based on obs. Was your hypothesis right or wrong? Conclusions – based on obs. Was your hypothesis right or wrong?

Carrots Exp. Hypothesis: Carrots fed a solution of high nutrients, such as apple juice or orange juice, will grow faster/better than other carrots Hypothesis: Carrots fed a solution of high nutrients, such as apple juice or orange juice, will grow faster/better than other carrots Materials: carrot tops, soil, 4x4 containers, apple juice, orange juice, water, pepto bismol, cola Materials: carrot tops, soil, 4x4 containers, apple juice, orange juice, water, pepto bismol, cola

Carrots Exp. Procedure: Procedure: top ends of carrots were cut off and planted in two inches of soil in the 4x4 container. top ends of carrots were cut off and planted in two inches of soil in the 4x4 container. Carrots were placed in a well lit area, each susceptible to the same conditions Carrots were placed in a well lit area, each susceptible to the same conditions Fluid solutions were made at a concentration of half water and half testable substance. Fluid solutions were made at a concentration of half water and half testable substance. Each carrot was “fed” once daily with each of the respective solutions: water, OJ, AJ, Pepto and cola. Each carrot was “fed” once daily with each of the respective solutions: water, OJ, AJ, Pepto and cola. Observations were taken over a period of 2 weeks on growth and appearance of carrots. Observations were taken over a period of 2 weeks on growth and appearance of carrots.

Carrots Exp. Observations: over a 2 week period Observations: over a 2 week period Water – grew to a height of 10 inches Water – grew to a height of 10 inches Apple juice – grew to a height of 2 inches, but shrivelled and died after 6 days Apple juice – grew to a height of 2 inches, but shrivelled and died after 6 days Orange juice – did not grow. Carrot top actually shrivelled and blackened over the 2 weeks. Orange juice – did not grow. Carrot top actually shrivelled and blackened over the 2 weeks. Pepto Bismol – growth was stunted and insignificant. Pepto Bismol – growth was stunted and insignificant. Cola – carrot blacked and died within 3 days. Cola – carrot blacked and died within 3 days.

Carrots Exp. Conclusion: It would seem that the “high nutrient solutions” were also high in acid content, which seemed to outright kill the plants. Conclusion: It would seem that the “high nutrient solutions” were also high in acid content, which seemed to outright kill the plants. Orange juice and had prompt, devastating effects. Orange juice and had prompt, devastating effects. Cola immediately destroyed the plant, due to its’ high acid and sugar content and lack of nutrients. Cola immediately destroyed the plant, due to its’ high acid and sugar content and lack of nutrients. Apple juice, slightly less harsh, allowed the plant to grow at first, until the concentration in the soil was too high. Apple juice, slightly less harsh, allowed the plant to grow at first, until the concentration in the soil was too high.

Carrots Exp. Water worked best, as expected. Water worked best, as expected. The pepto bismol results were curious and will need to be investigated further. There are many artificial compounds in the substance which could have effected the plant in a myriad of ways. The pepto bismol results were curious and will need to be investigated further. There are many artificial compounds in the substance which could have effected the plant in a myriad of ways.

Designing a good Experiment Making a good experiment can be hard. Making a good experiment can be hard. 1. Test only one variable at a time!!!!!! (Manipulated variable) 1. Test only one variable at a time!!!!!! (Manipulated variable) You need to control all of the variables other than the one you are testing. (controlled variables) You need to control all of the variables other than the one you are testing. (controlled variables) If you are testing how different amounts of water will affect plant growth than you need to control container size, type/amount of soil, amount of light, source of light, temp of room etc. If you are testing how different amounts of water will affect plant growth than you need to control container size, type/amount of soil, amount of light, source of light, temp of room etc.

Designing a good Experiment 2. You need to have a “control” 2. You need to have a “control” Control: a specimen/part of the experiment where the manipulated variable is unchanged. Control: a specimen/part of the experiment where the manipulated variable is unchanged. A control gives you something to compare the other results to. A control gives you something to compare the other results to.

Designing a good Experiment 3. Do as many trials and samples as possible. 3. Do as many trials and samples as possible. Having more samples in your experiment reduces the chances of a mistake or error occurring. Having more samples in your experiment reduces the chances of a mistake or error occurring. Single trial experiments don’t tell you much. How do you know that one of your plants wasn’t just sick or defective? Single trial experiments don’t tell you much. How do you know that one of your plants wasn’t just sick or defective?

Designing a good Experiment 1. Test only one variable at a time!!!!!! (Manipulated variable) 1. Test only one variable at a time!!!!!! (Manipulated variable) 2. You need to have a “control” 2. You need to have a “control” 3. Do as many trials and samples as possible. 3. Do as many trials and samples as possible.

What’s wrong with these experiments Joey Bloggs wanted to test how long it would take ice to freeze if it had different amounts of salt dissolved in it. Joey Bloggs wanted to test how long it would take ice to freeze if it had different amounts of salt dissolved in it. He set up 5 groups of 4 cups with varying amounts of salt and split them up between two different freezers. He set up 5 groups of 4 cups with varying amounts of salt and split them up between two different freezers. He checked his samples every 5 minutes to see how frozen they were. He checked his samples every 5 minutes to see how frozen they were. What about his samples is not consistent? What about his samples is not consistent?

What’s wrong with these experiments Kevin wanted to test the strength of different bridge designs: a dome, a square, a triangular and a diamond shaped bridge. Kevin wanted to test the strength of different bridge designs: a dome, a square, a triangular and a diamond shaped bridge. Each bridge was made out of a different material. Wood, lego, K’NeX and straws. Each bridge was made out of a different material. Wood, lego, K’NeX and straws. Why will results be difficult to draw from this test? Why will results be difficult to draw from this test?

What’s wrong with these experiments Stitch was trying to determine which fertilizer would make his plants grow best. Stitch was trying to determine which fertilizer would make his plants grow best. He set up 4 sets of 3 bean plants, each to receive a different fertilizer. He set up 4 sets of 3 bean plants, each to receive a different fertilizer. Set1 – NewGro, Set 2 – DoubleGro Set1 – NewGro, Set 2 – DoubleGro Set 3 – UltraGrow Set 4 – KindaGRO Set 3 – UltraGrow Set 4 – KindaGRO What was he missing?

What’s wrong with these experiments The Mythbusters tested how radiation would affect different insect. The Mythbusters tested how radiation would affect different insect. They took a equal numbers of three species of insect and subjected them to deadly gamma rays. They took a equal numbers of three species of insect and subjected them to deadly gamma rays. After one trial, they drew decisive conclusions and published them on their television show. After one trial, they drew decisive conclusions and published them on their television show. What was their error? What was their error?