Four lab experiments carry this 5-page 5th grade check on conservation of matter, matched to NGSS 5-PS1-2. Students predict weights for 150 g of melting ice and for salt dissolving in 100 g of warm water. They read before-and-after data for baking soda and vinegar in a sealed bag, then explain why the same reaction in an open bowl drops to 195 g. A sealed 30-gram glow stick closes the 11 questions, and the answer key gives the reasoning for each.
5-PS1-2
“Measure and graph quantities to provide evidence that regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight of matter is conserved.”
Every section. Questions 1 to 5 cover melting and dissolving, question 6 turns the sealed-bag data into a bar graph, and questions 8 to 10 test the rule with an open bowl and a glow stick.
Experiment A starts with 150 g of ice in a cup and asks what the melted water weighs. Experiment B adds a 15 g spoonful of salt to 100 g of water, and question 5 tests the claim that the salt is gone, so the water weighs less.
Baking soda and vinegar react in a sealed zip-top bag that weighs 200 g before and after. Students describe the bar graph they would draw and convert 200 grams to about 7 ounces.
The same reaction runs in an open bowl, and the weight falls from 200 g to 195 g. Students explain where the missing 5 grams went and whether matter was still conserved.
A sealed glow stick weighs 30 grams before it is cracked. Students predict its weight while it glows and state the rule of Conservation of Matter in their own words.
After the demo
Run the sealed-bag reaction on a scale at the front of the room, then set Section 2. Students trust 200 g before and after once they have watched the reading themselves.
Pair discussion
Section 3 works well with partners. The drop to 195 g looks like proof that matter vanished, so let pairs argue it out before anyone writes an answer to question 9.
End of topic
Use all 11 questions as the final check on the topic. The key shows the 115 g total for question 3 and model explanations for the written answers.
Get started today
