Scientific Procedure and Lab Safety Test next Friday/Monday on: 1.Lab Safety; steps and reading labelsLab Safetysteps and reading labels 2.Identifying a problem, writing a hypothesis, writing a conclusion 3.Data – quantitive and qualitative; inference versus observation 4.Independent variable, dependent variable, constant, control, repeated trials 5.Metric conversions

Lab Safety Never work alone in the lab Leave all backpacks, etc. in the classroom Do not pull out chairs and sit down No food or drink Read all label and make sure you know what materials are in each of the containers at your table. They should be labeled. Proper dress

Important Terms Flammable – how easily something will burn or ignite Disposal – method of getting rid of waste. Substances should not be put down the sink or thrown in the trash unless the teacher gives permission. Combustible – how easily something will explode Toxic – the degree to which a substance can damage a person or other organism.

What are SI units? International system of units used by the scientific community. It includes: meter for length kilogram for mass second for time ampere for electric current kelvin for temperature candela for luminous intensity mole for the amount of substance.

SI Conversions SI units are in tens.

Complete the worksheet and then on the back write down some examples of what you would use each of these units to measure.

What factors are Kept constant in this experiment?

Constant Things that are kept the same in an experiment.

What factors are Can you control in this experiment?

Independent Variable An independent variable is the variable you have control over. It’s what you can choose and manipulate. It is usually what you think will affect the dependent variable. Goes on the X axis

What factors is the result of the experiment that will make up your data?

Dependent VariableDependent Variable (Results) The dependent variable responds to the independent variable. It is called dependent because it "depends" on the independent variable. Goes on the Y axis

Variables and Controls Example #1 Ms. S. decides to test if flicking kids with rubber bands will get them to stop talking. She splits the class in half and flicks the half on the left every time they talk. She does not flick the kids on the right when they talk. Independent Variable: Dependent Variable: Control: Measurement: Constants:

Control Sometimes an experiment needs a basis for comparison – something you are NOT experimenting with.

Variables and Controls Example #1 Ms. S. decides to test if flicking kids with rubber bands will get them to stop talking. She splits the class in half and flicks the half on the left every time they talk. She does not flick the kids on the right when they talk. Independent Variable: Dependent Variable: Control: Measurement: Constants:

What could you add to this experiment that would be a control?

Variables and Controls Example #2 Katie wants her pumpkins to grow faster so she puts cow manure on 3 of her plants, chicken manure on 3, and humanure on 3. Independent Variable: Dependent Variable: Control: Constants:

Measurements Katie’s Data: Plant 1:.517 cm Plant 2: m Plant 3:.204 in If all plants were the same height at the beginning, which plant grew the most? What are some constants in this experiment?

Quantitative data vs. Qualitative data Qualitative – data or observations that are obtained through the five senses. Quantitative data – data that is collected as a result of scientific measurement usually with tools like a ruler, balance, graduated cylinder, etc.

Inference vs. Observation Inference – a conclusion drawn from an observation Observation – either quantitative or qualitative. These are limited to what you can measure or gather from your senses.