Bell Ringer Archive for Grades 9–12: Every Subject
Every bell ringer we have posted for grades 9–12, across all subjects: 10 bell ringers so far, newest first. Pick a subject below to see just that one, or read our guide to running bell ringers in high school.
ELA Bell Ringer for Grades 9–12: Three ways to fix a comma splice
This sentence is a comma splice. Fix it three different ways: once with a period, once with a semicolon, and once with a comma plus a conjunction.
The bus was late again, most of us missed the start of first period.
Answer and teacher notes
Period: The bus was late again. Most of us missed the start of first period.
Semicolon: The bus was late again; most of us missed the start of first period.
Comma + conjunction: The bus was late again, so most of us missed the start of first period.
A comma splice joins two complete sentences with only a comma. A comma alone can't hold two independent clauses together. Ask which version best shows that the second idea is caused by the first (the "so" version makes it explicit).
Math Bell Ringer for Grades 9–12: Comparing two-dice probabilities
You roll two fair six-sided dice and add the numbers. Which is more likely: a sum of 7 or a sum of 10? Give the probability of each as a fraction in lowest terms.
Answer and teacher notes
There are 6 × 6 = 36 equally likely outcomes.
Sum of 7: (1,6), (2,5), (3,4), (4,3), (5,2), (6,1) = 6 outcomes, so 6/36 = 1/6.
Sum of 10: (4,6), (5,5), (6,4) = 3 outcomes, so 3/36 = 1/12.
A sum of 7 is twice as likely as a sum of 10. Check: 1/6 = 2/12. The most common error is counting (4,6) and (6,4) as the same outcome; on two separate dice they are different.
Science Bell Ringer for Grades 9–12: Balancing the equation for burning methane
Natural gas is mostly methane (CH4). When it burns completely, it reacts with oxygen to make carbon dioxide and water. Balance the equation, then prove it is balanced by counting atoms on each side.
__ CH4 + __ O2 → __ CO2 + __ H2O
Answer and teacher notes
CH4 + 2 O2 → CO2 + 2 H2O
Atom count: carbon 1 = 1. Hydrogen 4 = 2 × 2 = 4. Oxygen 2 × 2 = 4 on the left; 2 (in CO2) + 2 × 1 (in water) = 4 on the right. Tip: balance C and H first, then O last, since oxygen shows up in both products. Students who change subscripts (writing H4O) have changed the substance, not balanced it.
Source: U.S. Energy Information Administration: Natural Gas Explained
Social Studies Bell Ringer for Grades 9–12: The 2010 rescue of 33 trapped miners in Chile
On this day in 2010, all 33 workers trapped by a collapse at the San José gold and copper mine in Chile's Atacama Desert were brought to the surface after 69 days underground. Imagine you led the team on the surface. List three problems you would need to solve to keep 33 people alive until a rescue was possible, and rank them from most to least urgent. Explain your top choice.
Answer and teacher notes
Answers will vary. Strong lists include finding out whether anyone survived and where they are, getting air, water, food, and medicine down to them, keeping communication open, protecting their mental health over weeks of waiting, and designing a safe way to lift people up. Reward rankings that are justified (for example, "locating them comes first because nothing else is possible until we know where they are").
Facts to share afterward: the collapse happened on August 5, 2010, and all 33 were brought up in a specially designed rescue capsule called Phoenix. Quick math: 69 days is just under 10 weeks.
Current Events Bell Ringer for Grades 9–12: Why polar sea ice peaked and bottomed out in the same week
NASA reported this week that Antarctic sea ice reached its yearly maximum on September 14, 2026, covering 17.59 million square kilometers. Just two days earlier, on September 12, Arctic sea ice hit its yearly minimum of about 4.6 million square kilometers. (a) Why would one pole's ice peak in the same week the other pole's ice is at its lowest? (b) About how many times larger was the Antarctic ice extent than the Arctic's?
Answer and teacher notes
(a) The hemispheres have opposite seasons because Earth is tilted on its axis. Mid-September is the end of winter in the Southern Hemisphere, after months of cold and darkness let ice build up, and the end of summer in the Northern Hemisphere, after months of sunlight melted it back.
(b) 17.59 ÷ 4.6 ≈ 3.8 times larger. NASA noted that this year's Antarctic peak was the third-lowest maximum since satellite observations began. Good follow-up: why do scientists compare each year to a long record instead of just to last year?
Sources: NASA Earth Observatory: Antarctic Sea Ice Grows to Its 2026 Maximum; NASA Earth Observatory: Arctic Sea Ice Shrinks to Its 2026 Minimum
ELA Bell Ringer for Grades 9–12: Active versus passive voice
Rewrite this sentence in the active voice so it is shorter and clearer:
The decision was made by the committee after the votes were counted.
Answer and teacher notes
Possible answer: The committee made the decision after it counted the votes.
In active voice, the one doing the action (the committee) comes first. Ask students who did each action; that is their subject.
Math Bell Ringer for Grades 9–12: Solving a linear equation
Solve for x, then check your answer: 3(x − 4) = 2x + 5
Answer and teacher notes
3x − 12 = 2x + 5 → x − 12 = 5 → x = 17
Check: 3(17 − 4) = 3(13) = 39, and 2(17) + 5 = 39. Both sides match. The most common error is distributing the 3 to x only and writing 3x − 4.
Science Bell Ringer for Grades 9–12: The physics of a 66-kilometer-per-second meteor
Orionid meteors enter Earth's atmosphere at about 66 kilometers per second. (a) How far does one travel in 3 seconds? (b) The grains are about the size of sand. Why do they glow and burn up instead of reaching the ground?
Answer and teacher notes
(a) 66 km/s × 3 s = 198 km.
(b) At that speed the grain slams into the air in front of it. That air is squeezed and heated so fast that the grain heats up and vaporizes, which is the streak of light we see. Students often say "friction"; that is part of it, but compressed, superheated air does most of the work.
Source: NASA: Orionids Meteor Shower
Social Studies Bell Ringer for Grades 9–12: The Columbian Exchange
After 1492, plants and animals crossed the Atlantic in both directions, a process called the Columbian Exchange. Name one that went from the Americas to the rest of the world and one that went to the Americas. Then explain how one of them changed people's daily lives.
Answer and teacher notes
From the Americas: corn (maize), potatoes, tomatoes, cassava. To the Americas: horses, cattle, pigs, wheat.
Strong examples: horses changed how Plains nations hunted and traveled, and potatoes helped feed Europe's growing population. Diseases crossed too and caused a massive decline in Indigenous populations, which is worth raising if students only list foods.
Source: Britannica: Columbian Exchange
Current Events Bell Ringer for Grades 9–12: Whether towns should dim their lights for the night sky
The Orionid meteor shower peaks the night of October 21–22. NASA's advice is to watch from somewhere far from city and street lights. Some towns limit bright outdoor lighting at night to protect the view of the sky. Would you support a rule like that where you live? Give one reason for it and one reason against it.
Answer and teacher notes
Answers will vary. Reasons for: darker skies, less wasted energy, less disruption to wildlife. Reasons against: safety and visibility at night, cost to businesses, people's right to light their own property. Grade the reasoning, not the side they choose.
Source: NASA: Orionids Meteor Shower
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