Looking for evidence of bubbles coming from the ingredi…

3.B Plan and carry out an investigation to collect data to identify patterns in the characteristic properties of substances from a bath bomb when they are individually added to water.

• Looking for evidence of bubbles coming from the ingredients when they are placed in water.
• The physical observation of what happened to each ingredient when it was added to water.
• Testing only one ingredient at a time so that they know what ingredient is potentially responsible for producing the bubbles.

If you see groups rushing from one test to the next, without first writing down their observations for the previous one, remind those groups that detailed observations are important for providing evidence for future arguments. If you notice some students not participating, or not being included, remind the small group of the class norms and ask them how they could alter what they are doing so that all of them are contributing members of the investigation.

Students may offer several ideas. Accept all and discuss as a class how to keep track of them in a data table. Some suggestions students may make might include, temperature, mass, color change, thickness change, etc.✱

Solicit ideas for recording data. Work together as a class to determine a way to organize their data, keeping in mind that they will add the rest of the ingredients when groups share their data with the class. Draw their suggested data table on the board. Tell students they should make a data table in their notebooks also to keep track of the data they collect for the ingredients they test.✱

Carry out the investigation. Display slide K. Give each team Lab Procedure for Mixing the Ingredients in the Water and their set of assigned ingredients to test in water using the visual procedure on the slide. This student investigation should take no more than 10 minutes.

Report the results. Display slide L. Ask a few students to report what they saw happen to each ingredient when it was added to water. They can bring their labeled cups up to the front of the room and line them up on the front table as they report their results for other groups to see, if you wish. Ask students to also compare how this was the same or different from bath bombs interacting with water. Encourage students to add ingredients that they did not test to their data table. Each student should have data for each ingredient after everyone has shared.

Suggested prompts

Sample student responses

Follow-up questions

Okay, so we are trying to figure out what causes the gas bubbles in the bath bomb. Looking at our class data, can we come to any conclusion about what causes the gas bubbles?

• Not really…because none of the ingredients resulted in gas bubbles.
• None of these ingredients bubbled when we put them in water.

What other patterns in the data do you notice?

What does that information tell you?

Was there anything all the ingredients had in common?

There wasn’t a gas made for any of the ingredients when mixed with water.

What did this data tell you?

Was there anything in the data that was different between the ingredients after being mixed with water?

Some of the ingredients looked as if they didn’t mix with the water--they just floated on top of the water.

Which ingredients were those?

Some ingredients dissolved in the water and the liquid looked clear. But others looked cloudy or milky.

Do you think the ones that looked milky dissolved like the ones that looked clear? Why or why not?

You said some ingredients “dissolved.” Do you have ideas about how that happens? What does it mean to dissolve?