Teacher Guide

Students who stop at the smell crossing the room. Push one step further: what carried the smell? The particles did, and nobody saw them.

Students who try to explain why air is see-through. The page does not, on purpose: water and glass are see-through too, with their particles packed close. The point is only that see-through is not the same as nothing.

Any student who suggests tasting the water. Nothing is tasted in this book, and the drying test is better evidence anyway, because you can see it.

Students who say the water in row d disappeared. Ask where it is now; the answer is the air, and the word is evaporate.

The hands-on part uses milk and vinegar because it makes no gas. If anyone tries the balloon version from page 2 for real, a kitchen scale will read the balloon bottle 1 to 3 grams light: the swollen balloon is pushed up by the air around it, the way water pushes up on a boat. The matter is all still there, and a student who notices the drop has observed something real.

Students who match on one property only. P and R both fail to dissolve and both do not fizz; only the feel tells them apart.

Students who think every metal is pulled by a magnet. Aluminum is a metal and is not, which is why the row is there.

Students who call dissolving a reaction because the salt seems to disappear. Week 3 showed it is still there and can be got back.

Students who think the salt was lost when it dissolved. It went through the filter with the water and came back when the water evaporated.

Students who say the closed jar did not evaporate. Some water may evaporate inside it and condense on the lid; it just cannot leave.

This is the most common wrong idea in all of elementary science, and adults hold it too. Let the numbers do the arguing.

Students who say plants get their food from the soil. The page's answer is that they make it; the soil gives water and a little else.

Students who count the sun or themselves as living things in the chain. The hint says to leave both out; the sun is not alive.

Students who say the energy was used up. It was not: it became motion and warmth and spread into the surroundings. Grade 4 held this line all year.

Students who answer the second question by counting the right-hand column for the wrong animal. Turn the table around, as the hint says.

Keep the bags sealed, every time, and throw them away still sealed. Mold spores can bother people with allergies or asthma.

Students who say the compost disappeared. Like week 4's dish, ask where it went. The decomposers breathed it out.

Students who think the foxes caused the rabbits to go up. The rabbits rose first; the foxes followed a year later.

Students who start the journey with the clover. The particle was in the air before the clover took it in. The question says to count the decomposers: they took the particle in as they fed, and breathed it back out.

Students who put the glacier in the geosphere because it is solid. It is frozen water.

Students who name only one sphere per row. Every row is an interaction, so there are always two.

These are real estimates, not practice data, rounded to whole squares. Scientists put the ocean at about 96.5 of every 100 liters, fresh water at about 2.5 and ice at about 1.7; the page says about, and that is why. Page 1's bottle uses the same estimates to the milliliter: about 25 of 1,000 fresh, about 17 of those frozen.

Bars drawn without using the scale. Each grid line is 5,000 liters, so 9,000 is just under the second line.

Students who pick d because it is cheapest. It is inside the budget and misses the goal by a long way.

Students who say the numbers prove the trash cans worked. They are good evidence; proof would need ruling out the other explanations.

Students who say heavy things fall faster. The ball, the eraser and the crumpled paper weigh very different amounts and landed together.

Students who draw the people at the bottom upside down and falling off. Ask them which way their own feet point.

Students who say the capped bottle's plants used up its water. The water went into the plants and the air inside, and is all still there.

Students who expect the shortest shadow at exactly 12. On daylight saving time the sun is highest closer to 1 p.m. in California; in winter, near noon.

Students who only count the hours the shadow shrank. The question asks for the biggest change either way; the afternoon growth is smaller.

Students who say the sun goes around the Earth. The flashlight model never moves the light; only the ball turns.

Students who think stars move around the sky over the year on their own. It is the Earth that moved.

Students who expect twice the distance to give half the light. It gives a quarter, because the light spreads over a patch that is wider AND taller.

Students who say the sun is the biggest or brightest star. Many stars give off far more light; the sun is simply close.

Students who rank designs by how good they look. The list decides, which is the whole point of writing it first.

Students who put row e under too far because trees are big. It is about the particles of air and water the tree is built from.