Scientific Method

Jasmine entered the school science fair competition Jasmine entered the school science fair competition. She wanted to see if colored light affected plant growth. However, when several other students repeated Jasmine's procedure, they all obtained different results than Jasmine's. What do the different results mean? A. The other students should design their own experiments about light. B. The results will probably be different every time an experiment is conducted. C. Jasmine's results should be accepted since she conducted the experiment first. D. Jasmine's results should not be accepted because scientific results should be repeatable.

Sam is conducting an experiment with pendulums; he thinks that more massive objects will swing faster. He is testing whether the mass of the swinging object has an effect on how long it takes to make one swing. He tests two different masses and collects the data shown in the table. What should Sam do based on these results? A. Throw out the data because it doesn't support his hypothesis. B. Do more trials to see if the difference in time really is significant. C. Conclude that less massive objects always take more time to swing. D. Conclude that more massive objects always take more time to swing.

Steps to Scientific Method OBSERVATIONS Main Process of Gathering Data Use this data to come up with…… QUESTIONS What do you want to know or find out? HYPOTHESIS Possible Answer to Questions Must be testable and able to be proven false DATA COLLECTION & ANALYSIS Perform experiment to get data Analyze data with tables & graphs MULTIPLE TRIALS (What and Why?) Do experiment more than once Cancels out mistakes CONCLUSION Summarize results; what you learned Hypothesis correct / incorrect

A Controlled Experiment Part of the scientific method

Variables A factor that can change. A variable can change other factors when it changes. Examples of variables: -Temperature -Light - Open vs. Closed container -Location -Time -Elevation -Pressure

Independent vs. Dependent Variables The dependent variable is a factor that changes because the independent variable changes. However the independent variable is not changed by the dependent variable. Example: Elevation and Boiling temperature of water. The boiling temperature of water changes because of changes in elevation. Changes in the boiling temperature of water do not change elevation.

Control -A variable or factor that does not change in the experiment. It remains constant. In a Controlled experiment only one variable is allowed to change at a time. Everything else remains constant.

Francisco Redi & Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Maggots appear on the meat. HYPOTHESIS: Flies produce maggots. Uncovered jars Covered jars VARIABLES Constants: jars, type of meat, location, temperature, time After several days Independent Variables: gauze (keeps flies away from meat) Dependent Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Seed Germination Gizmo

(Extension) Alka-Seltzer Lab

Exit Ticket  1. Colleen waters the plants in her greenhouse once every day. She wants to find out if the plants will grow more leaves if they are watered more often. She counts the number of leaves on each plant before she starts. She then continues to water half of each type of plant once daily, but she waters the other half of each type twice a day. What is the dependent variable in Colleen's experiment? A. the type of plant being grown B. the number of leaves the plants grow C. the amount of light the plants receive D. the number of times the plants are watered   2. Christy wants to find out if the birds that visit the bird feeders in her backyard would rather build nests in birdhouses or in trees. She puts a birdhouse next to the feeder containing sunflower seeds and hangs a feeder containing cracked corn from a tree. She observes the birds' nesting activities over the next two weeks and records her observations. Which of the following would improve Christy's investigation? putting more food in both bird feeders setting the feeders up closer to each other putting the same kind of food in both bird feeders setting up a third bird feeder containing fruit near a bird bath 3. Randy's science teacher is giving a demonstration to show how a metal reacts with different acids. He places a small piece of the metal in each of three beakers containing a solution of a different acid. He adds a piece of the metal to a fourth beaker that contains only water. What is the purpose of the fourth beaker? It ensures that the hypothesis will be correct. It provides more data to include in a lab report. It adds an independent variable to the experiment. It is the control and serves as the basis for comparison.

WATER ABSORBENCY OF PAPER TOWELS 4. Curtis conducts an investigation to determine which brand of paper towels is the most absorbent. He records his findings in the table below. WATER ABSORBENCY OF PAPER TOWELS What is the test variable (independent variable) in this investigation? the liquid used the brand of paper towels the amount of water absorbed the time the towels absorbed water 5. The following bar graph shows the population of bacteria under different temperature ranges. What can be concluded about the bacteria from reading this graph? They thrive at exactly 30°C. They cannot tolerate temperatures above 50°C. They prefer temperatures between 20°C and 30°C. They prefer warmer temperatures to cooler temperatures.