Notes

What is the primary difference between a hypothesis and a theory?=A theory is supported by more data and observations than a hypothesis is.

The data from one particular experiment do not agree with a current theory. What is the next step?=Try to repeat the data from the experiment.

What term is missing from the central region that describes hypotheses, theories, and laws?=falsifiable

Maya observes that adding sodium hydroxide to a clear liquid causes the liquid to turn pink. She hypothesizes that the sodium in the sodium hydroxide caused the color change. She tests her hypothesis by adding six other solutions that contain sodium to the liquid. The liquid does not change color. What is the best thing for Maya to do next?=Modify her hypothesis, and design new experiments to test it.

Stewart notices that crickets seem to chirp more on warm nights than on cold nights. He decides to count the number of times that the crickets chirp on a cold night. What should be his next step?=Count the number of times that they chirp on a warm night, and compare the numbers.

When may a hypothesis be revised?=based on experimental data

A scientist develops a new experiment to test atomic theory. His results do not agree with the theory. What will most likely happen next?=The scientist will repeat the experiment to make sure that his results are reliable.

Jenna is a scientist in a chemistry lab. Her experiment did not support her current theory. What should she do next?=Verify the data by running the experiment several more times.

Jia observes that adding a solution of sodium hydroxide to a clear liquid turns the liquid pink. She makes a hypothesis about why the liquid changed color. Which characteristic is least important for her hypothesis to have?=based on the opinion of her classmates

Which is one way that scientists communicate the results of an experiment?=drawing a picture

A scientist studies the effect of adding different amounts of salt on the boiling point of water. He places his results in the graph below.What are the independent and dependent variables in this experiment?=Mass is the independent variable, and boiling point is the dependent variable.

In an investigation that uses the scientific method, which step immediately follows asking a question?=creating a hypothesis

During a conference presentation, a scientist described the materials that she used and how she performed her experiments. Which best explains why a scientist would share these details in a conference?=It informs the audience if the study included controlled tests.

A scientist wants to use a model to help present the results of his detailed scientific investigation. Why would a model be useful?=because the model makes the concepts easier to understand

A student needs a model that she can use to find the amount of gas in a container that looks like a cylinder of radius R and height H. She is considering using one of the following models.Which model is the better one to use and why?=model A because it can be directly used to find volume

Which method is the typical first step when scientists communicate their scientific results?=submitting the results to a scientific journal for a peer review

The MSDS for a solution of hydrochloric acid (HCl) indicates that it is a stable chemical that is toxic and corrosive. The MSDS gives HCl a health rating of 3, a flammability rating of 0, a reactivity rating of 2, and a contact rating of 3. Which statement is applicable to the HCl solution?=The HCl solution can cause severe burns to skin tissue.

The MSDS for chloroform indicates that it is a clear liquid that has a pleasant smell and substantial vapor pressure. Its health rating is 2, fire rating is 0, and reactivity rating is 0. People should avoid inhaling its vapors, avoid skin contact, and avoid ingesting it. It is sensitive to light and can react with alkalis and certain metals. According to this information, how should chloroform be stored?=in a closed, dark container in the fume hood

What is one advantage of using a computer over a graphing calculator?=Computers hold larger amounts of data.

What is a caliper used for?=to make a precise measurement of length

How many milliseconds (ms) are there in 3.5 seconds (s)?=3,500 ms

Sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple. Which of these tools should she use for this purpose?=a stopwatch

Which tool can be used to measure the volume of a liquid to one decimal place?=a graduated cylinder

Rob measures the solubility of three different salts in water at 22°C. Which type of graph should he use to display his data?=bar graph

The actual density of iron is 7.874 g/mL. In a laboratory investigation, Jason finds the density of a piece of iron to be 7.921 g/mL. What is the percent error that is associated with Jason’s measurement?=0.6%