PHAbiotic factor

Acidity and Alkalinity (Base) Acidity:

Extra hydrogen (H+) ionsVery reactiveLemon juice and vinegar

Alkalinity (base):Extra hydroxyl (OH -) ionsLaundry detergent and Sea water

pH Scale Measures how acidic or basic a substance is Scale of 0 to 14

Less than 7 is acidicGreater than 7 is basic (alkaline)7 is neutral

Each whole pH value is ten times more acidic/basic than the next higher/lower value.Examples:

○ pH 4 is ten times more acidic than a pH of 5○ pH 8 is ten times more basic than a pH of 7

Effects on animals and plants Most aquatic animals/plants live in a

specific pH and may suffer from changes in the pH.Success of fish eggs hatching drops, irritate

fish gills, amphibians deaths, etc.. Acid rain

Effects plant/animal life, possibly death

Variables

Experiments

cause and effect relationships in nature Way of knowing how nature works by changing one variable

and predicting how it will effect other variable. Variables: a factor, trait, or condition that can happen in

differing amounts or types

Types of Variables Control:

Remain constant/ stays the same Used to compare how something has changed

Independent: variable that is changed by scientists Only change one thing at a time for best results

Dependent: May change due to the independent variable Response variable

Classifying Variable Type Examples1. A student wants to know “Does heating a cup of water

allow it to dissolve more sugar?” In preforming his experiment he uses the same type of sugar and amount of sugar for each test. He also puts the same amount of water into the cup each time. He changes the temperature of the water in the cup and observes the dissolving of the sugar to answer his question. What is the independent variable?

temperature What is the dependent variable?

Amount of sugar dissolved What are the controlled variables?

Type of sugar, amount of water, cup, etc…

Classifying Variable Type Examples A student wants to know: “Does fertilizer make a plant grow

bigger?” The student gathers pots, fertilizers, plant, soil of the same type to prepare for her experiment. She then plants her plants in the pots and makes sure that each gets the same amount of water and light for a given amount of time. She then varies how much fertilizer each of her plants gets. She observes her plants over the next few weeks measuring their height and number of leaves.

What is the dependent variable? Height and number of leaves

What is the independent variable? Amount of fertilizer

What are the controlled variables? Fertilizer type, pot size, plant, soil type, water and light amount, etc…

Classifying Variable Type Examples Your teacher wanted to know: “Would the amount of eggs in a chocolate

chip cookie recipe change the height of a cookie?” She then went to the store and bought the ingredients for her experiment. She kept all the ingredients the same, but for each batch she made she changed the number of eggs she put in. She also kept the oven temperature the same. When the cookies came out of the oven, she would measure the cookies with a toothpick by sticking it in the middle and marking it at eye level. She then measure the toothpick with a ruler.

What is the independent variable? Amount of eggs

What is the dependent variable? Height of the cookies

What are the controlled variables? The ingredients, oven temperature, measuring the cookies in the middle,

etc…