Before and After — Weighing Matter (PS.5.1.1)
You blow up a balloon with air and then tie it. When you weigh it, it’s heavier than before. Why might that be?
A. Air has no mass.
B. The air made the balloon lighter.
C. Air has mass and takes up space.
D. The balloon stretched, so it weighs more.
C. Air has mass and takes up space.
You stir sugar into water, and it disappears. Later, you taste it and it’s still sweet. Did a new substance form?
A. Yes, it became a chemical change.
B. No, it’s a mixture because the sugar is still there.
C. Yes, because the sugar can’t be seen.
D. No, because the water evaporated.
B. No, it’s a mixture because the sugar is still there.
You leave a crayon in the sun, and it melts. When it cools, it hardens again. What type of change is this?
A. Physical change — it can return to its original state.
B. Chemical change — new substance formed.
C. Both physical and chemical change.
D. No change — it stayed the same.
A. Physical change — it can return to its original state.
When ice melts into water, what kind of change occurs?
A. Chemical
B. Physical
C. Both
D. None
B. Physical
Which source provides the energy that powers the water cycle?
A. The moon
B. The sun
C. The wind
D. The ocean
B. The sun
A student burns a small piece of paper and notices ashes left behind. The ashes weigh less than the original paper. Where did the missing mass go?
A. It disappeared.
B. It turned into gas and released into the air.
C. It was absorbed by the ashes.
D. It melted into the pan.
B. It turned into gas and released into the air.
A student mixes vinegar and baking soda and sees bubbles form. What do the bubbles tell us?
A. The vinegar got warm.
B. A gas was formed — a new substance.
C. The baking soda melted.
D. It was only a physical change.
B. A gas was formed — a new substance.
A baker mixes dough and puts it in the oven. After baking, the bread is fluffy and brown. Why can’t it go back to dough?
A. It cooled down.
B. A physical change happened.
C. A chemical change happened.
D. The oven absorbed the dough.
C. A chemical change happened.
You leave iron nails outside, and they rust after a week. What kind of change is this?
A. Physical
B. Chemical
C. No change
D. Reversible
B. Chemical
When water from lakes and oceans turns into water vapor, what process is happening?
A. Condensation
B. Evaporation
C. Precipitation
D. Transpiration
B. Evaporation
Two students dissolve salt into a cup of water and say, “The water seems the same.” If they weigh it before and after, what would they find?
A. The weight stays the same.
B. The water weighs less.
C. The water weighs more.
D. The salt disappears completely.
A. The weight stays the same.
You mix sand and iron filings, then use a magnet to pull out the iron. What does this tell you about the mixture?
A. It was a chemical change.
B. It was a solution.
C. It was a physical mixture.
D. It was a new substance.
C. It was a physical mixture.
Engineers design materials that resist melting for space shuttles. Why do they test how materials respond to heat?
A. To see which ones look the best.
B. To find materials that don’t change shape or properties at high temperatures.
C. To make sure the shuttle gets hotter faster.
D. To reduce the shuttle’s mass.
B. To find materials that don’t change shape or properties at high temperatures.
A student measures the weight of a cup of water before and after freezing it. What will they discover?
A. The weight decreases.
B. The weight stays the same.
C. The weight doubles.
D. The ice disappears.
B. The weight stays the same.
Plants release water vapor through their leaves. What is this process called?
A. Transpiration
B. Condensation
C. Evaporation
D. Precipitation
A. Transpiration
When a metal nail rusts over time, it feels rougher and looks different. Does the nail’s total weight change if all the rust stays on it?
A. The weight increases slightly.
B. The weight decreases slightly.
C. The weight stays the same.
D. The weight disappears.
A. The weight increases slightly.
Lemon juice and milk are combined, and the milk curdles into chunks. What type of change happened?
A. A physical change — it can go back to milk.
B. A chemical change — new substances formed.
C. No change — it just mixed unevenly.
D. A freezing process.
B. A chemical change — new substances formed.
A plastic bottle left in the freezer cracks. What can we infer about how cooling affects materials?
A. Cooling makes materials expand.
B. Cooling makes materials contract or become brittle.
C. Cooling makes things melt.
D. Cooling makes materials grow stronger.
B. Cooling makes materials contract or become brittle.
You mix flour and water to make dough. What kind of change happens when it’s still cold and not baked?
A. A physical mixture.
B. A chemical reaction.
C. A new substance forms.
D. The flour disappears.
A. A physical mixture.
Clouds form when water vapor cools and changes back into liquid drops. Which process is this?
A. Evaporation
B. Condensation
C. Precipitation
D. Transpiration
B. Condensation
A student mixes vinegar and baking soda in a closed plastic bag. The bag fills with gas and looks different after the reaction. When the student weighs the bag before and after, the weight stays the same. Why does the weight stay the same?
A. Some of the matter disappeared when the gas formed.
B. The gas has no mass, so it doesn’t affect the weight.
C. The matter stayed inside the closed bag, just changed form.
D. The reaction made the bag lighter.
C. The matter stayed inside the closed bag, just changed form.
A student mixes two clear liquids. The mixture becomes warm and turns cloudy. What evidence shows a new substance formed?
A. It got heavier.
B. The liquid cooled down.
C. It changed temperature and appearance.
D. It looked the same after mixing.
C. It changed temperature and appearance.
An inventor is testing different materials to make a reusable water bottle. One material keeps water cold for hours, while another gets warm quickly. What property is the inventor testing?
A. How well each material conducts heat
B. How strong each material is
C. How much each material weighs
D. How flexible each material is
A. How well each material conducts heat
Which observation best shows a chemical change?
A. Ice melting
B. Paper tearing
C. Candle wax melting
D. Burning wood producing smoke and ash
D. Burning wood producing smoke and ash
Rain, snow, sleet, and hail falling from clouds to Earth are examples of what process?
A. Evaporation
B. Transpiration
C. Condensation
D. Precipitation
D. Precipitation