Measurement definitions/instruments
Used to measure mass (or weight of an object)
What is a balance/scale?
What you manipulated (or purposefully changed) over the course of an experiment.
What is an independent variable?
In a data table, how can we identify whether a variable is controlled?
Looking at the trials/stages of an experiment, if the value of a variable is the same (or constant) throughout the course of the experiment then it is controlled.
This digit is listed after recording what you are sure of on a measuring device.
What is an estimated digit?
Used to measure volume.
What is a beaker?
What is a graduated cylinder?
What is an Erlenmeyer flask?
Variable measured that remains constant over the course of an experiment?
How does the number of Alka-Seltzer tablets dissolved into a beaker of vinegar affect its final temperature?
Identify the independent variable, dependent variable, and list 1-2 controlled variables.
Independent - Number of Alka-Seltzer tablets
Dependent - Final temperature of alka-seltzer & vinegar mixture
Controlled - Room pressure & Initial temperature
When viewing a liquid through a container and when we need to make a measurement, we are looking for the _____.
Meniscus.
Used to make more precise measurements of volume.
What is a graduated cylinder.
During the experiment, this variable's change responds to the change that you make.
What is an dependent variable?
How do we differentiate an independent variable from a dependent variable?
An independent variable is one that we change ourselves and the dependent is one that we watch AFTER we make some tweak or manipulation in our experiment. (Anything along these lines works as an answer)
Before you can record a measurement on something like a graduated cylinder, you need to be able to read the _____ on the measurements.
You need to be able to read the ticks and what they represent. For example, if you have a difference of 1 between the numbers listed and you have 5 spaces, your value goes up by 0.2 each time you move up. ( The unlabeled tick after 1 here would be 1.2, then the one after is 1.4, and so on)
How we should find and record an answer for the volume of a liquid.
Squat or hold the graduated cylinder at eye-level where the meniscus will meet your eye. Be sure to be able to read the ticks in between measurements listed on a graduated cylinder and record a measurement with an estimated digit after what the instrument can give you. (For example, if the instrument records the tens and ones place, you estimate the tenths place i.e. 24.3 where 3 is estimated)
A quantity that is measured and/or recorded over the course of an experiment.
What is a variable?
Will changing the volume of alcohol in a boiling point experiment change the boiling point of the liquid?
Identify the independent variable, dependent variable, and list 1-2 controlled variables.
Independent variable - Volume of alcohol
Dependent variable - Boiling point of alcohol
Controlled variable - room pressure, type of alcohol used, & heat setting
Record the measurement for the liquid listed on the board.
4.33-4.37 are acceptable answers.
How to find and record the volume of an amorphous solid (one without a clear shape like triangle, square, etc.)
Grab a volumetric container and measure the volume. After the recording this first volume, drop the object and allow it to sink and now record the new measurement of the liquid. The difference of the first and second measurements of volume is the volume of the solid.
Explain the experiment for "Model 3 - Boiling Points of Alcohols" -- what procedure did they follow? Explain the instruments they used and how they came up with a table of values recorded.
Using beakers to measure 75 mL (or the same volume of liquid) for five different alcohols. (1 for methanol, ethanol, propanol, butanol, and pentanol or alcohols with different numbers of carbons) These beakers are heated up on a hot plate with a thermometer inserted. As the hotplates are left, we watch for signs of bubbling/vapor and record the temperature on the thermometer of the alcohol to indicate its boiling point.
*There also must be some apparatus to measure the room pressure (barometer -- we will talk about this later).
Will changing the surface area of an ice cube make it melt faster?
Identify the independent variable, dependent variable, and list 1-2 controlled variable.
Independent - changing surface area
Dependent - melting rate
Controlled - the solid in question is water in ice form, all are placed in the external environment (outside with same exposure to sun), etc.
Record the measurement for the liquid on the board.
5.27-5.33