Maya wants to find out whether more sunlight helps a bean plant grow taller. She gives one plant 8 hours of light each day and the other plant 2 hours. What must she keep the same for both plants?

Ben tested whether a ball rolls farther on carpet or on wood. On the carpet he rolled a light tennis ball, and on the wood he rolled a heavier rubber ball. Why can he not trust his result?

A class is studying shadows on the playground. Sara asks, "Are morning shadows prettier than noon shadows?" Ana asks, "How does shadow length change from morning to noon?" Whose question can be tested?

Liam draws a model of a meadow food chain: grass, then grasshopper, then mouse, then hawk. His teacher says one group is missing. What should he add to show where the matter in a dead hawk goes?

In a forest model, arrows show energy moving from the Sun to a plant and then to a deer that eats the plant. A student adds an arrow sending energy from the deer back to the plant. Why is that arrow wrong?

A fallen oak leaf lies on the forest floor for a year and slowly disappears from sight. A model of the ecosystem must show where the matter in that leaf goes. Where does it go?

Kim seals the tip of a syringe and pushes the plunger in. The air inside takes up less space, and no air leaks out. Which claim does this evidence best support?

A sealed jar holding water and 20 grams of sugar weighs 250 grams on a balance. The lid stays on, the sugar dissolves, and the balance still reads 250 grams. Which claim does this evidence support?

True or False: A claim in science is stronger when it is supported by measurements that other people can repeat.

A class models the water cycle with a bowl of warm water under a cold lid. Their diagram shows water leaving the bowl and returning only as rain from the lid. But drops gather on the cold lid before any drop falls. What should they do with the model?

A class measured a flagpole's shadow at 9 a.m., at noon, and at 3 p.m. on one sunny day. The noon shadow was the shortest of the three. What pattern does this evidence support?

Two students time how long a marble takes to fall from a table. Their first trial gives 0.9 seconds. What should they do before they write a conclusion about the falling time?

A ball let go in Australia falls toward the ground, and a ball let go in Canada also falls toward the ground. Which claim does this evidence best support?

A river has slowly cut a deep valley through a rocky hillside over many years. Which interaction between two of Earth's systems does this observation give evidence for?

A student's model of the Earth system labels groundwater as part of the atmosphere. Where does groundwater belong instead, and why?

Two samples were tested. Sample A is shiny and is not attracted to a magnet. Sample B is shiny and is attracted to a magnet. A student needs a shiny metal that a magnet can hold. Which sample fits?

Iron filings are stirred into a dish of dry sand. A student holds a magnet over the dish and pulls the iron filings back out. What does this evidence show?

A team builds a model bridge from drinking straws on a classroom desk to stand for a real steel bridge over a river. What is the main weakness of this model?

Engineers claim their new school water bottle meets the requirement of holding 1 liter. Which measurement would best support that claim?

A student models the water cycle with a covered bowl of warm water and a cold lid. Drops form on the underside of the lid and fall back into the bowl. What does this model show well?