The best science bell ringers start with “why.” Why does the metal spoon get hot? Why is the sky blue? Kids already have a guess. Your job is to make them commit to it before class starts, so the lesson has something to push against.

Below are 40 science bell ringers: 20 for middle school and 20 for high school. Teacher notes with the key idea for each one are tucked under every section, so you can project the questions without spoiling them.

Three kinds of science bell ringers that work

  • Predict. “What happens if…?” Make them write a prediction before they know the answer. Being wrong is fine. Not committing isn’t.
  • Explain something they’ve seen. Fogged-up breath, a cut apple turning brown, leaves changing color. Everyday stuff they’ve never really thought about.
  • Design a test. “How would you find out if…?” Great practice for variables and fair tests, and it takes zero materials.

Science bell ringers for middle school (grades 6–8)

  1. You leave a metal spoon and a wooden spoon in a bowl of hot soup. A minute later, one is much hotter to touch. Which one, and why?
  2. Why do we have seasons? (Hint: it’s not because Earth gets closer to the Sun.)
  3. Put one ice cube on a plate and hold another in your hand. Which melts faster? Why?
  4. Name the three common states of matter and give an everyday example of each.
  5. You put a healthy plant in a dark closet for a week. Predict what it looks like when you open the door. Explain.
  6. Why can you “see your breath” on a cold morning but not on a warm one?
  7. Write a food chain with four links using animals and plants that live near you.
  8. Is a virus alive? Make a case for yes or no.
  9. You roll a ball across the floor. Why does it eventually stop?
  10. Burning paper and cutting paper: which is a physical change and which is a chemical change? How can you tell?
  11. The Moon doesn’t actually change shape. So why does it look different during the month?
  12. What would happen to a pond if all the frogs suddenly disappeared? Think about what they eat and what eats them.
  13. Why would you weigh less on the Moon even though your body is the same?
  14. Design a fair test to find out if fertilizer makes plants grow faster. What will you change? What will you keep the same?
  15. Steel is heavier than water. So how do giant steel ships float?
  16. How could an igneous rock eventually become a sedimentary rock?
  17. Why does a cut apple turn brown if you leave it out?
  18. Which has more mass: a kilogram of feathers or a kilogram of bricks?
  19. Why does your body sweat when you’re hot? How does that help?
  20. Why do some leaves turn yellow and orange in the fall? Write a hypothesis.
Teacher notes: grades 6–8
  1. The metal spoon. Metals are good conductors, so heat moves through them quickly. Wood is an insulator.
  2. Earth’s tilted axis. When our half of Earth tilts toward the Sun, we get more direct sunlight and longer days. (NASA Space Place)
  3. The one in your hand. Your hand transfers heat to the ice faster than the room air does.
  4. Solid (ice), liquid (water), gas (water vapor or air). Plasma is a fourth state if your class has covered it.
  5. Pale or yellow and droopy. Plants need light to make food through photosynthesis.
  6. Your breath has water vapor. On a cold day it cools fast and condenses into tiny droplets you can see.
  7. Answers vary. Check that it starts with a producer (a plant) and the arrows point toward the eater.
  8. Answers vary, and that’s the point. Viruses have genetic material, but they aren’t made of cells and can’t reproduce without a host cell. Scientists still argue about this one.
  9. Friction between the ball and the floor (and a little air resistance) slows it down.
  10. Burning is chemical: new substances form (ash, smoke) and you can’t undo it. Cutting is physical: it’s still paper.
  11. The Moon always has a sunlit half. As it orbits Earth, we see different amounts of that lit half. (NASA)
  12. Look for both directions: insects the frogs ate might boom, and animals that eat frogs (herons, snakes) might struggle.
  13. Weight is the pull of gravity on your mass. The Moon’s gravity is much weaker than Earth’s, so you weigh less. Your mass doesn’t change.
  14. Change: fertilizer or no fertilizer. Keep the same: plant type, pot size, soil, water, light. Measure: height over time.
  15. A ship’s shape spreads its weight out and pushes aside (displaces) a huge amount of water. The ship as a whole, air inside included, is less dense than the water.
  16. Weathering and erosion break it into sediment, which gets deposited, buried, and pressed together over time.
  17. The inside of the apple reacts with oxygen in the air. That’s a chemical change.
  18. Neither. A kilogram is a kilogram. Great one to catch kids rushing.
  19. Sweat evaporates off your skin, and evaporation carries heat away, which cools you down.
  20. As days shorten, leaves stop making green chlorophyll and it breaks down, which unmasks yellow and orange pigments that were there all along. (USDA Forest Service)

Science bell ringers for high school (grades 9–12)

  1. Balance this equation: H₂ + O₂ → H₂O
  2. Why is the sky blue during the day?
  3. Give an example of Newton’s third law from a sport you know.
  4. Name one difference between mitosis and meiosis.
  5. A runner covers 100 meters in 12.5 seconds. What’s her average speed?
  6. Why do cities spread salt on icy roads?
  7. Two parents are both Bb for a trait where B is dominant. What fraction of their offspring would you expect to show the recessive trait?
  8. Why don’t antibiotics work against a cold?
  9. Describe where a roller coaster has the most potential energy and the most kinetic energy.
  10. A solution with pH 3 is how many times more acidic than one with pH 5?
  11. On the Moon, an astronaut dropped a hammer and a feather at the same time. What happened, and why?
  12. An object has a mass of 50 g and a volume of 20 cm³. What’s its density? Will it float in water?
  13. Explain the greenhouse effect in three sentences.
  14. Why do cells divide instead of just growing bigger and bigger?
  15. A 2 kg ball accelerates at 3 m/s². What net force is acting on it?
  16. A forest burns down. Describe what grows back first, and what comes later.
  17. Why are noble gases like neon so unreactive?
  18. A circuit has a 12-volt battery and a 4-ohm resistor. What’s the current?
  19. Explain how bacteria can become resistant to an antibiotic over time.
  20. Design an experiment to test whether music affects heart rate. Name your independent, dependent, and controlled variables.
Teacher notes: grades 9–12
  1. 2H₂ + O₂ → 2H₂O. Four H and two O on each side.
  2. Sunlight scatters off gas molecules in the air, and blue light scatters more than other colors because it travels in shorter waves. (NASA Space Place)
  3. Answers vary. A swimmer pushes the wall back, the wall pushes the swimmer forward. A batter’s bat hits the ball, the ball pushes back on the bat.
  4. Mitosis makes two identical body cells. Meiosis makes four sex cells with half the chromosomes, each genetically different.
  5. 8 m/s. 100 ÷ 12.5 = 8.
  6. Salt lowers the freezing point of water, so ice melts at temperatures where it otherwise wouldn’t.
  7. 1/4 (25%). The Punnett square gives BB, Bb, Bb, bb. Only bb shows the recessive trait.
  8. Colds are caused by viruses. Antibiotics target structures bacteria have, like cell walls, which viruses don’t have.
  9. Most potential energy at the top of the highest hill. Most kinetic energy at the bottom of the biggest drop, where it’s moving fastest.
  10. 100 times. Each step on the pH scale is a factor of 10, so two steps is 10 × 10.
  11. They hit the ground at the same time. With no air on the Moon, there’s no air resistance, so everything falls at the same rate. (NASA, Apollo 15)
  12. 2.5 g/cm³. 50 ÷ 20. It sinks, because water’s density is about 1 g/cm³.
  13. Look for: sunlight warms Earth’s surface, Earth gives off heat, and certain gases in the atmosphere trap some of that heat, keeping the planet warmer than it would be otherwise.
  14. As a cell grows, its volume grows faster than its surface area. Eventually the membrane can’t move materials in and out fast enough.
  15. 6 newtons. F = ma = 2 × 3.
  16. Secondary succession. Grasses and small fast-growing plants first, then shrubs, then trees over many years.
  17. Their outer electron shell is already full, so they have no “need” to gain, lose, or share electrons.
  18. 3 amps. I = V ÷ R = 12 ÷ 4.
  19. Natural selection. A few bacteria happen to survive the antibiotic. They reproduce, and over time more of the population carries that resistance.
  20. Independent: music or no music (or type of music). Dependent: heart rate. Controlled: same person, same time of day, sitting still, same length of listening.

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