Look for: If the gas from the bath bomb puts out a flam…

5.B Apply scientific reasoning based on patterns in the densities for a known set of gases to explain how either of two different possible outcomes from a future investigation could help us narrow down the sub-set of candidate substances from what could be in the unknown gas from the bath bomb.

in student responses on My Predictive Explanations for the Gas from a Bath Bomb:

If the gas from the bath bomb puts out a flame above it, that means it is __less____ dense than the room air, which has a known value between ___1.160 to 1.161 g/L_____. I know this because ____ materials that are less dense float upward when surrounded by matter that is more dense_______. If evidence supports this prediction, it tells me that the gas from a bath bomb could be __neon, and/or helium ___________.

If the gas from the bath bomb puts out a flame below it, that means it is __more____ dense than the room air which has a known value between ___1.160 to 1.161 g/L_____. I know this because ____ materials that are more dense sink downward when surrounded by matter that is less dense_______. If evidence supports this prediction, it tells me that the gas from a bath bomb could be __nitrogen, argon, and/or carbon dioxide___________.

If you notice students are struggling when they are forming these for the first time, you could pause the activity. Then talk through the responses and rationale for what they would put in each of the blanks on slide I, together as a whole class for the first prediction. You could then have them individually write their understanding of what you just discussed, and have them try the same for the second prediction shown on slide J. For students who need additional scaffolding for this explanation, use Alternate: My Predictive Explanations for the Gas from a Bath Bomb that has sentence starters and other supports.

Supporting Emerging Multilingual Learners

Scaffolds such as sentence starters and images can model and facilitate particular oral or written language production skills. Such scaffolds may be of particular benefit for emerging multilingual students to help them develop language skills to write or communicate their ideas to peers. It is important that scaffolds be used purposefully and removed when no longer needed. To support this, a modified handout has been made available Alternate: My Predictive Explanations for the Gas from a Bath Bomb.