ETS1 - Engineering Design
Students test their SCL model and observe how the SCL functions during descent, landing and ascent with the attached scientific instruments.
Cross-cutting Concepts - Appendix G
Cause and Effect - XC2
Students attach 'scientific instruments' (cause) to the SCL and observe what happens (effect) when the SCL is released in water.
Structure and Function - XC6
Students observe how changing the structure of the SCL, by adding the 'scientific instruments' possibly changes the function of the SCL.
Making Observations - SP 3
Students make observations of the SCL to see if it meets the criteria for descending, landing and ascending with scientific instruments.
Have 'One Step At a Tme' set for 'phase 4'
Round up eight 5 gallon buckets for the SCL 'test tank'. Fill the buckets with water the day before the lesson.
A deli was throwing away buckets that were used for pickles.
Locate rags for teams to use to dry off the canister between ascent testing.
Purchase alka seltzer, 4 tablets / team is plenty.
Place 4 tablets in a baggie (8 baggies)
Have attachment material available
1 baggie with 4 tablets
Team instrument baggie
Part 4 of the SCL Lab booklet
We start science by meeting on the rug to read our 'science question for the day', which is usually posted on the board.
This allows students to time to consider today's topic before the lesson has officially begun. I have established this routine with the kiddos to keep transition time short and effective and redirect student's attention back to content while allowing time for focused peer interaction.
Before students are directed to the rug, I ask them to bring their SCL lab booklet to the rug.
Question for the Day: For a successful descent, landing and ascent, what should your team's soda cup lander, with the scientific instruments attached, be able to do?
The question refers to a our discussion in the last lesson.
"Please turn to your neighbor and share your ideas." I call on students to share.
I expect students to share that the SCL should land level, the instruments should stay on and that the it can ascend.
I remind students that this criteria is in their lab booklet and direct them to look at this section of their booklet, Part 4, page 12. I point out the criteria and the observation form.
After you have had 3 successful descents and landings your team will use the 'fuel cell' and observe how the SCL ascends with the attached scientific instruments.
"Let's review how the SCL ascends. The alka seltzer bubbles, pushing out the water in the canister and cup. The bubbles get trapped under the cup, and since the air is less dense than the water, the cup rises."
Students have seen a demonstration of the SCL ascend in previous lessons.
"Engineers, your SCL may not rise, so it will be up to you figure out what you may need to do to solve this problem."
"Please take your pencil and lab book and sit at your team tables. When you meet with your team discuss what you could do to help your SCL ascend."
This gives the students a focus for their team discussion as I pass out team materials.
Students are working in groups. I am sure this part will seem a little chaotic, a little messy, but the kids will be engaged. I think the biggest challenge for some students will be to take the time to make the careful observations and to go slowly. Sometimes students get caught up in the doing and do not want to be bothered with taking the notes.
I project 'phase 4' on the board.
Day Two - Testing Ascent and Dscent
Phase 4 Engineers test the descent and landing of the SCL and make observations
"Each team member will take observation notes. This page is in your lab book, p. 12. You will observe how the SCL descends; is it a level descent, if it lands smoothly, and do the instruments stay in place.
I explain that if their SCL does not work, to show how they modified their SCL on their diagram. They are given the choice to make a new diagram or use a pen on their original diagram to show their modifications.
Only a few teams took the time to record how they changed the SCL on the diagram. Teams were caught up in the quest to make it work. I did not want to interrupt them. Students were on task and working enthusiastically with their team.
Next time I do this lab, I will ask students to make a diagram to show the final design for the SCL after all testing is complete.
"Even if there are no modifications needed, you will test your SCL 3 times, 3 trials. Think about how many times James Cameraon tested that the weights dropped off the Deepsea Challenger. Why is it important for engineers to test their design more than once?"
I call on teams to share.
Teams discovered that the 'launch' was an important aspect on how well the trials went. If the air was not dumped out of the cup before placing in the water the SCL would not sink.
In a previous lesson, part 1 students tested how to release the cup so that it would sink. So it may be just taking a moment and reminding them of this step.
It was challenging for some teams to come up with a way to have the instruments stay attached to the SCL, but all teams persevered and had 3 successful trials for the descent and landing. On to the ascent.
Phase 5 - Practice loading the film canister
Students meet me on the rug to discuss phase 5. I start by reminding students what an alka seltzer (their fuel cell) does in water.
"You will be using a fuel cell today to see how your your SCL ascends. Would it matter if your film container was not closed all the way? Does water enter the canister right away? Think about what you saw with the alka seltzer demonstration."
I demonstrate how to open and close their film canister. I pass out the team baggies and send teams back to their table to practice loading the pretend 'fuel cell' into the canister.
With all the handling of the SCLs canisters, the magnet that was glued to the inside of the film canister has come off, so we have had to modify how we load the canister.
The materials are stacked on the inside of the lid in this order: magnet (make sure the correct pole is against the lid), alka seltzer, pennies. Then the inverted canister is pushed into the lid. Then the canister is carefully picked up and placed into the cup. Check that the magnets are attached then you can turn the cup over. (attach video)
After team members have practiced loading the film canister, teams place their instruments on their SCL and prepare them for their final trials: descent, land ascend.
Phase 6 - Testing the SCL with the fuel cell
When I see most teams have the SCLs ready, I signal to students to meet me on the rug.
"Each team will receive 4 fuel cells. Your team numbers are on the fuel cells." I hold up a baggie with the fuel cells. If the cells get wet, I am not sure they will work. So do not pick up your cells until you are absolutely sure that your SCL descends and lands safely with instruments attached. Between each trial, dry off the film canister. Why would I suggest this?"
"If you see that you need to modify your steps because the SCL acts differently under 'fuel'. Write this in your observations, and use the space underneath to make a diagram. Your team should be asking why did the SCL do this."
Take careful observations, as these will be useful for design modifications and to write up your recommendations for the marine scientists." (link to lesson)
15 minutes before class is over, I call out the remaining time , "You have 5 minutes, before I will ask you to stop. Consider what you will finish in these 5 minutes.
I do this so students can mentally change gears and find a stopping point that works for them.
After 5 minutes, teams are directed to:
- remove and dry off instruments and SCL
- open the film canister and dry off pennies, lid and canister
- throw away any used alka seltzer
- wash hands
Later I will pour out the water in the planters.
When most students are seated at their desk. I congratulate my engineers and share any observations I noticed about the teams, such as they were all on task and working well with their team.
I explain that later this week they will use their observations to explain to the marine biologists which instruments they would recommend for the SCL and where these should be placed on the lander and why.
"Today though, I would like you to look through your lab book and write a note to me what you liked or did not like about working with the SCL."
I am doing this to bring closure to this portion of the unit and to give students an opportunity to reflect on what they liked and did not like about the labs.