Experiments Laboratory activities and experiments require us to do things in a standard way so they can be repeated by anyone to get the same result. These are organized into steps called the Scientific Method.

Step 1: Objective The Problem that the laboratory activity is to solve (Purpose). Written as a question. Like “How can I get more sugar to dissolve in water?”

Step 2: Research/Information Gathering information about the subject before the activity. Find out what is known or has already been discovered about the subject. Like “Water is easy to heat up or cool down.”

Step 3: Hypothesis Suggested solution or proposed explanation for a problem or observation. Written as an “If…then” statement. If (independent), then (dependent variable). Like “If I raise the temperature of the water, then more sugar will dissolve in the water.”

Independent Variable Factor that does not “depend” on anything. If there are a few independent variables, only one is changed at a time to see its effect. The others are kept constant, known as Controls. What are some independent variables for this experiment?

Independent Variable Examples Container (metal, ceramic, insulated, thick) Type of water (city, well, bottled, filtered) Type of sugar (plant, pure, powder, granules) Freshness of sugar and water Amount of sugar and water Temperature of water Temperature of room Humidity (moisture in the air or the sugar)

Dependent Variable The factor you want to know that is being tested or measured. Its value can change since it “depends” on the independent variable. Like the amount of sugar that dissolves depends on the temperature of the water.

Step 4: Experiment Test the Hypothesis Control the independent variables and measure the dependent variables.

Observation Using your senses (what the scientist sees, hears, feels, smells, or tastes) to collect data. Data = measurements and information.

Step 5: Analysis Use tables and graphs Figure out what the information reveals.

Step 6: Conclusion Result of a laboratory activity. Explain the data in words and tell if it supports the Hypothesis.

Scientific Method Steps Objective Research/Information Hypothesis Experiment Analysis Conclusion

1) Write a Hypothesis If salt is sprinkled on an icy sidewalk, then the ice melts even when the temperature is below freezing because… Hypothesis: … salt changes (lowers) the water’s melt (or freeze) temperature by fitting between water molecules and preventing them from locking together in a solid lattice.

2) Write a Hypothesis If fish hatch in water that is mixed and aerated (like a river), then they survive better than hatching in stagnant water (pond) because… Hypothesis: …mixing adds enough air to the water that the fish now have enough oxygen to survive.

3) Write Independent and Dependent Variables, Controls and Concerns Mike put 100 red seeds, 100 brown seeds, & 100 yellow seeds in a bird feeder. He counted the number of each color left after 2 days. Independent Variables: Seed color Dependent Variables: Number of colors left Control Variables: 100 of each seed to start, same bird feeder, 2 days time for each color Concern: season, seed size, height, mix, preds

4) Write Independent and Dependent Variables, Controls and Concerns Liz tested how high 5 brands of golf balls would bounce when dropped from a height of 2 meters off of the same floor tile each time. Independent Variable: Brands of golf balls Dependent Variable: Bounce height Control Variables: 2 meter start height, bounced off of same original floor tile Concern: dropper, temperature, humidity

Ch1 Scientific Method Analysis You heat white, black and gray cans in hot water to study whether the color of a container affects how fast it cools down. Write a Hypothesis (If…then statement) List the Independent Variable List the Dependent Variable List the Controls (at least 3) List the Concerns (at least 3)