Hilburn Physical Science Lesson 3 Outline

load

A (n) ______is a force applied to a structure from the structure itself.

trusses

A (n) truss bridge is supported only at its two ends, but is strengthened by an assembly of interconnected triangles, or ______.

independent variable

A factor in an experiment that is manipulated or changed by the investigator is called the _________.

controlled experiment

A type of scientific investigation that tests how one factor affects another is called a(n) _____________.

overloaded

After thorough modeling and analysis, investigators ruled out the idea that the bridge failed due to being_________.

constants

All the factors in an experiment that do not change are called _______.

variable

Any factor in an experiment that can have more than one value is called a(n)_____________.

qualitative data

Data that use words to describe what is observed in an experiment are called ___________.

damaged

Evaluating why the collapse occurred was difficult because emergency workers unintentionally _____________the bridge.

long

One disadvantage of beam bridges is that they tend to sag in the middle if they are too ______.

beam bridge

The simplest type of bridge, called a(n) _________________has one horizontal beam across two supports.

quantitative

The use of numbers to describe what is observed is called _________________data.

Qualitative

____________data uses words to describe what is observed.

scientific inquiry

In order for investigators to determine why the bridge failed, they needed to use many parts of ________.

gusset plates

Inspection of recovered_____________ showed that some of the plates failed very early in the collapse.

percent

Investigators could not determine if undersized plates were used because of mistaken calculation, a(n) ___________error, or some other error in the design process.

positions

Investigators eventually recovered the entire structure and placed the various places in their relative original _______.

video

Investigators found more clues in a(n) ___________from a motion- activated security camera.

collapsed

Investigators studied various questions to determine why the bridge __________ or if a combination of factors caused the bridge to fail.

live load

Temporary loads to a structure such as traffic, wind gusts, or earthquakes are called _______________.

truss bridge

The I-35W bridge was a(n) _______________designed in the early 1960s.

node

The area where the truss structure connects to the roadway portion of the bridge gusset plate is called a(n) _________.

gusset plates

The beams in the bridge's deck and the triangular and vertical supports came together at structures known as __________.

bridge

The center section of the Interstate 35W __________________in north Minneapolis, Minnesota, suddenly gave away on August 1, 2007.

dependent variable

The factor that a scientist observes or measures during an experiment is the ________.

engineering

The failure of the bridge was a surprise because the design and __________________processes that bridges undergo are supposed to ensure that bridge failures do not happen.

control group

The group that contains the same factors as the experimental group, but the independent variable does not change, is called_________.

experimental group

The part of a controlled experiment used to study relationships among variables is the ______________.