Transcript PPT
Science 7 Seating Plan 702 Seating Plan 701 Review From Previous Class All work that has been handed in has been corrected (Pass Back) What are the steps of the scientific method? What is the difference between a inference and a hypothesis? Hypothesis A hypothesis is: an educated guess or proposition that attempts to explain a set of facts or phenomenon. Hypothesis A hypothesis should always: Explain what you expect to happen Be clear and understandable Be testable Be measurable Contain an independent and dependent variable Ex: Tim and Moby stated their hypothesis as “Fig plants do best if you only water them once a week” Hypothesis It is usually written in the form: If__________ then ________ will happen because___________________________. Based on our observations, inferences and background knowledge we can make a TESTABLE hypothesis Hypothesis Writing From your observations and inferences determine: which part you can control and manipulate (Independent Variable) Which part we can’t control but what may change based on our other manipulations (dependent variable) It also doesn’t hurt to identify other variables that may have an effect, but that you would attempt to keep the same in an experiment (controlled variables) Hypothesis Writing From what you’ve identified you can write your hypothesis in the: “If_____ then_____ because _______” format. If independent variable, then dependent variable, because _________________. Practice: Writing a Hypothesis 1. 2. 3. 4. 5. Observations Salt in soil may affect plant growth. Temperature may cause leaves to change color. Sunlight causes fruit to ripen more quickly. Bacterial growth is affected by temperature Ultraviolet light may cause skin cancer. Hypotheses 1. _________________ 2. _________________ 3. _________________ 4. _________________ 5. _________________ Practice: Writing a Hypothesis Observations 1. 1. Salt in soil may affect plant growth. 1. 1. Temperature may cause leaves to change color. 1. 1. Sunlight causes fruit to ripen more quickly. 1. 1. Bacterial growth is affected by temperature. 1. 1. Ultraviolet light may cause skin cancer. Hypotheses If salt in soil affects plant growth, then plants grown in higher salt content soil will grow slower than low salt content soil. If temperature causes leaves to change color, then plants exposed to cooler temperatures (less than 15°C) should change color faster than plants exposed to warmer temperatures (above 15°C) If sunlight causes fruit to ripen more quickly, then fruit kept in the dark should ripen slower than fruit kept in direct sunlight. If bacterial growth is affected by temperature, than food kept at a lower temperature (below 4°C) should have less bacterial growth than food kept at room temperature. (above 4°C) If ultraviolet light causes skin cancer, then rates of skin cancer occurrence will be higher in people exposed to higher amounts of UV light (ie: tanning bed users, not using sunscreen). Practice- Worksheet Using the problem and observations given, create a hypothesis to explain what’s happening. Describe how you might test your theory If the page given doesn’t provide enough space please feel free to use the back side or looseleaf When completed- name and put in Pass In Bin