The Scientific Method Making a Good Experiment. The Scientific Method Is the driving force for all scientific progression. Is the driving force for all.
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The Scientific MethodMaking a Good Experiment
The Scientific MethodIs the driving force for all scientific progression.
Is based on gathering evidence through an experiment and drawing a conclusion from that evidence.
RememberThe scientific method does not strive to prove what is true.
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.
RememberNo matter how much evidence you have, or certain of the truth you might be, you can never be 100% certain.
Misinformed in the past:Four element theory.Earth being flat.Pleasant scents fighting sickness.
Where it BeginsIt 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 know whether a 2L bottle of pop will go flat faster if I do not squeeze the bottle before sealing it.
Background ResearchIt 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.
The HypothesisA prediction about the results of the experiment before you run it.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.Note: it is okay for a hypothesis to be wrong**
The ExperimentHypothesisMaterials all materials used in the experimentProcedure a step by step set of instructions, written in past tense. Exact numbers/amounts should be used.Observations what you observedConclusions 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
Materials: carrot tops, soil, 4x4 containers, apple juice, orange juice, water, pepto bismol, cola
Carrots Exp.Procedure: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 conditionsFluid 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.Observations were taken over a period of 2 weeks on growth and appearance of carrots.
Carrots Exp.Observations: over a 2 week periodWater grew to a height of 10 inchesApple juice grew to a height of 2 inches, but shrivelled and died after 6 daysOrange juice did not grow. Carrot top actually shrivelled and blackened over the 2 weeks.Pepto Bismol growth was stunted and insignificant.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.Orange juice and had prompt, devastating effects.
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.
Carrots Exp.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.
Designing a good ExperimentMaking a good experiment can be hard.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)
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 Experiment2. You need to have a control
Control: a specimen/part of the experiment where the manipulated variable is unchanged.
A control gives you something to compare the other results to.
Designing a good Experiment3. Do as many trials and samples as possible.
Having more samples in your experiment reduces the chances of a mistake or error occurring.
Single trial experiments dont tell you much. How do you know that one of your plants wasnt just sick or defective?
Designing a good Experiment1. Test only one variable at a time!!!!!! (Manipulated variable)2. You need to have a control3. Do as many trials and samples as possible.
Whats wrong with these experimentsJoey 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 checked his samples every 5 minutes to see how frozen they were.What about his samples is not consistent?
Whats wrong with these experimentsKevin 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, KNeX and straws.
Why will results be difficult to draw from this test?
Whats wrong with these experimentsStitch 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.Set1 NewGro, Set 2 DoubleGro Set 3 UltraGrow Set 4 KindaGROWhat was he missing?
Whats wrong with these experimentsThe 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.After one trial, they drew decisive conclusions and published them on their television show.
What was their error?