Write informative texts that report a scientific experiment and narrate a historical event, with a thorough thesis, organized sections, precise vocabulary and a significant conclusion

Learning goal: Write informative/explanatory texts, including the narration of historical events, scientific procedures and experiments, and technical processes: establish a clear and thorough thesis to present information; introduce a topic and organize ideas, concepts and information to make important connections and distinctions, including formatting such as headings, graphics such as figures and tables, and multimedia when useful to aiding comprehension; develop the topic with well-chosen, relevant and sufficient facts, extended definitions, concrete details, quotations or other information and examples appropriate to the audience's knowledge of the topic; use varied transitions and sentence structures to link the major sections, create cohesion and clarify the relationships among ideas and concepts; use precise language and domain-specific vocabulary to manage the complexity of the topic and convey a style appropriate to the discipline, the context and the expertise of likely readers; establish and maintain a formal style and objective tone that follows the norms and conventions of the discipline; and provide a concluding statement or section that follows from and supports the information presented, for example by articulating its implications or significance.

Informative is not argumentative. An argument defends a position that someone could reject. An informative or explanatory text presents information so that a reader understands it: what happened, how a process works, what an experiment did and found. It still needs a thesis, but the thesis presents information rather than a disputed claim: "Sliding friction between these wooden surfaces was measured with a spring scale and found to be approximately proportional to the normal force, with a coefficient of about 0.30." That sentence is clear (a reader knows what the report is about) and thorough (it states method, finding and scope).

Introduce and organize to make connections and distinctions. The introduction states the topic, its context and the thesis. The organization then follows the logic of the information. A scientific procedure or experiment report uses the discipline's conventional sections: purpose, materials, procedure, results, discussion, conclusion. These are formatting choices with a purpose: headings let a reader find the method without reading the results, and they make the distinction between what was done and what it means. A narration of a historical event is organized in time, but it is not a list; it groups events into phases and marks the turning points, so that connections (this caused that) and distinctions (this preceded that) are visible. Graphics belong where they aid comprehension. A results table lets a reader compare three conditions at a glance; a labeled diagram of the pulling setup shows "level with the board" faster than a sentence can. Multimedia, such as a short video of the slide or a linked data sheet in a digital report, is useful when motion or a changing data set matters; it is decoration when it repeats the text.

Develop with well-chosen, relevant and sufficient information. Well-chosen means each fact serves the thesis; relevant means it belongs to this topic; sufficient means a reader could follow or repeat what you describe. Develop the topic with the kinds of information the standard names. Facts: the masses, forces and readings. Extended definitions: a definition that goes beyond one line, giving the term, its category, what distinguishes it and an example or condition; "Kinetic friction is the force that acts along two surfaces while they slide past each other, opposing the sliding; it differs from static friction, which acts while the surfaces are not sliding over each other, and for dry, rigid surfaces it is approximately proportional to the normal force." Concrete details: "the scale was held level with the board," not "the setup was correct." Quotations: in history, a source's exact words; in science, a quotation is used sparingly, usually for a definition or a published claim. Examples: one worked calculation of μ_k. Choose the amount by the audience's knowledge: a report for classmates who did the lab can skip defining "spring scale" but must define μ_k; a report for younger students would define both.

Transitions and varied sentence structures. Cohesion across sections comes from transitions that name relationships: sequence ("first," "once the block was moving"), cause ("because," "as a result"), contrast ("whereas," "by contrast"), and illustration ("for example"). Varied sentence structures carry relationships too: a subordinate clause ("Because the block moved at constant velocity, the pull equaled the friction force") shows cause inside one sentence; a short sentence after long ones gives emphasis ("Contact area made no measurable difference."). Varied does not mean random: each structure should match the relationship it expresses.

Precise language and domain-specific vocabulary. Precise language manages a complex topic by naming exactly one thing at a time. "Force," "normal force," "kinetic friction" and "maximum static friction" are four different quantities; a report that calls all of them "the force" cannot be followed. Domain-specific vocabulary conveys a style appropriate to the discipline and to the expertise of likely readers: a physics teacher expects "coefficient of kinetic friction," while a general reader may need it glossed once in parentheses.

Formal style and objective tone within the discipline's conventions. Science reports use the past tense for what was done ("the block was pulled"), the present tense for general relationships ("kinetic friction is proportional to the normal force"), units on every quantity, and no emotional language. History narratives use the past tense, name sources for any quotation, and separate what the sources record from what the writer infers. Objective tone does not mean hiding uncertainty; it means stating it plainly: "the three readings ranged from 1.4 to 1.6 N."

A concluding section with implications or significance. The conclusion follows from the information presented: it summarizes the main finding and states what it implies or why it matters. For the friction report: the finding implies that adding weight to a sliding object increases friction proportionally, which is useful, and that the coefficient must be measured for each pair of surfaces, which is a limit.

Original model informative text — Measuring Sliding Friction: A Report (hypothetical data from the friction text).

Purpose. This report explains how the kinetic friction between a wooden block and a wooden board was measured and presents the results. Sliding friction between these surfaces was found to be approximately proportional to the normal force, with a coefficient of kinetic friction of about 0.30, and the block's contact area made no measurable difference.

Background. Kinetic friction is the force that acts along two surfaces while they slide past each other, opposing the sliding. For dry, rigid surfaces it is approximately equal to μ_k F_N, where F_N is the normal force, the surfaces' perpendicular push on each other, and μ_k is a coefficient that depends on the materials.

Procedure. First, the block (0.500 kg) and two 0.500 kg masses were weighed. The spring scale was then zeroed while held horizontally, since a scale zeroed vertically reads incorrectly when held level. Next, with the board lying flat on the bench, the block was pulled along it at a slow, steady speed, with the scale level with the board, and the steady reading was recorded after the first 10 cm. Three trials were run at each of three total masses, and three more with the block on its narrow side.

Results. Table 1 shows the mean readings. Because the block moved at constant velocity, each reading equals the kinetic friction force.

Table 1. Columns: total mass; normal force F_N; mean kinetic friction f_k; μ_k.

- 0.500 kg; F_N = 4.9 N; f_k = 1.5 N; μ_k = 0.31.
- 1.000 kg; F_N = 9.8 N; f_k = 2.9 N; μ_k = 0.30.
- 1.500 kg; F_N = 14.7 N; f_k = 4.4 N; μ_k = 0.30.
- 0.500 kg, narrow side down; F_N = 4.9 N; f_k = 1.47 N; μ_k = 0.30.

Discussion. When the normal force doubled, friction roughly doubled; when it tripled, friction roughly tripled. By contrast, turning the block on its side changed the mean by less than 0.1 N, smaller than the 0.2 N spread among trials.

Conclusion. For these surfaces, friction grows in proportion to the normal force and does not depend measurably on contact area. The practical implication is that a heavier load on the same surfaces needs a proportionally larger pull; the limit is that μ_k must be measured anew for any other pair of materials.

Original model narration of a historical event (from the fictional Harmon Falls sources). On the night of 25 March 1913, after three days of continuous rain, water began to pond behind the railroad fill that crossed the river bottom east of Harmon Falls's Mill Ward. Men in the town were saying that its single culvert was "choked with drift," as the schoolteacher Clara Whitlock recorded in her diary. At about two the next morning the fill gave way, and the water held behind it rushed into the Lower Ward at once. By daylight, water stood to the second-floor windows on Front Street, where families such as the Pruitts were lifted from upstairs windows into rowboats. Within three days the water fell, and on 29 March a Relief Committee began registering families in the schoolhouse, which had served as a shelter since the first night. The flood had lasted less than a week, but the sequence of its first night, ponding, failure and surge, would shape the town's arguments about responsibility for years.

Worked thesis and introduction: Draft introduction: "Friction is very interesting. We did a lab about it." It names a topic but presents no information. Revised: "This report explains how the kinetic friction between a wooden block and a wooden board was measured and presents the results. Sliding friction between these surfaces was found to be approximately proportional to the normal force, with a coefficient of kinetic friction of about 0.30, and the block's contact area made no measurable difference." The revision states the topic, what the report will do (explain the measurement and present the results), the main findings with a number, and the scope ("these surfaces"), so it is clear and thorough.

Worked check of the table: Each μ_k in Table 1 is f_k ÷ F_N, rounded to two decimal places: 1.5 ÷ 4.9 ≈ 0.306 → 0.31; 2.9 ÷ 9.8 ≈ 0.296 → 0.30; 4.4 ÷ 14.7 ≈ 0.299 → 0.30; narrow side 1.467 ÷ 4.9 ≈ 0.299 → 0.30. Compute from the unrounded mean (1.4 + 1.5 + 1.5) ÷ 3 ≈ 1.47 N: rounding it to 1.5 N first and then dividing would give 0.31, a double-rounding error. Each F_N is mass × 9.8 N/kg: 0.500 × 9.8 = 4.9; 1.000 × 9.8 = 9.8; 1.500 × 9.8 = 14.7. The table is a graphic that aids comprehension because it makes the pattern (friction rises with F_N, μ_k stays about the same) visible in one glance, which the same results written as sentences (section 5 of the friction text) do not.

Worked revision for precise language, transitions and sentence variety: Draft: "We pulled it and it read 1.5. Then we added weight. It went up. Then we added more. It went up again. Then we flipped it. It stayed the same." Every sentence has the same structure, "it" refers to three different things, and "then" is the only transition. Revised: "With no added mass, the steady kinetic reading was 1.5 N. When the normal force was doubled to 9.8 N, the friction force rose to 2.9 N, and when it was tripled, to 4.4 N. By contrast, turning the block onto its narrow side left the reading at about 1.5 N." The revision names each quantity precisely, gives units, uses a subordinate clause to show the condition, and uses "by contrast" to mark the key distinction between the two variables.

Section plan (representation): Before drafting, lay out your report as a set of headings (Purpose, Background, Procedure, Results, Discussion, Conclusion for an experiment; or phases with dates for a historical narration). Under each heading write one sentence stating that section's job, list the facts, extended definitions, concrete details and quotations it will use, and mark where a table, figure or multimedia element would aid comprehension and why.

Independent performance: Write an informative text of 450 to 600 words, either a report of an experiment or procedure you carried out in science (the friction trial is acceptable) or a narration of a historical event from your history unit with at least two sources. Success criteria: (1) a clear and thorough thesis that presents information and states its scope; (2) headings and at least one table or figure that aids comprehension, with a sentence referring to it; (3) at least one extended definition and several concrete details, quantities with units in science or quoted and cited words in history; (4) varied transitions and at least three sentence structures that clarify relationships; (5) precise domain-specific vocabulary suited to your stated audience; (6) formal style, objective tone and the discipline's conventions of tense and citation; (7) a conclusion that follows from the information and states its implications or significance.