STEM How To: Build a Popsicle Stick Catapult

Today marks the start of a new series here on Miss Sky's Classroom: STEM How To! This will be a series of posts relating to various STEM Challenges available in my TPT store, giving the instructions on how to create a basic model that satisfies the challenge requirements. The first model we are going to tackle is popsicle stick catapults!

Materials for one model:

7 popsicle sticks

3 rubber bands 

1 plastic spoon

Tape (I used standard scotch tape, but any tape will do)

Step 1:

Stack 5 of the popsicle sticks on top of one another - this stack will become the fulcrum which gives the catapult its firing angle.

Step 2:

Tape both ends of the stack, approximately 1cm from the end. I find it's best to wrap the tape 2-3 times for security so the stack doesn't slip when the pressure is applied.

The fulcrum is now complete!

Step 3:

Take the remaining 2 popsicle sticks and tie a rubber band around one end, at least 1cm from the end. This tie must be tight enough to keep the 'arms' together, however, be sure not to tie it so tight that it has minimal elasticity left or it may snap or pop off!

Step 4:

Pull the arms apart just wide enough to wedge the fulcrum part way in. Place the fulcrum so that it is centred across the arms and approximately two-thirds of the way to the rubber band.

Step 5:

 

This step is (in my opinion) the trickiest! I'm going to do my best to explain my rubber-banding technique used in the above photos, but essentially you can do whatever works to keep the parts together!

Start at the open side of the arms and loop the rubber band around twice. On the second loop twist the rubber band and bring it down so the loop finishes underneath the closed end of the fulcrum, creating a cross much like the one in the third picture. Then create another cross to tighten the elastic. You can repeat the process so you have a cross on the bottom of the catapult, however, this isn't necessary provided you have a band hitting each corner where the fulcrum and arms meet.

It should look something like this at the end of step 5!

Step 6:

Insert the spoon so that it sticks through most (if not all) of the layers of elastic on the top from the previous step. 

Step 7:

Tie the final elastic around the spoon and the end of the top arm. This elastic isn't integral to the functioning of the catapult so it needn't be too tight. However, it does give that little bit of added security to ensure the spoon doesn't go flying along with whatever you are launching!

And there you have it! A completed popsicle stick catapult!

If you are interested in using this in your classroom, please head over to my Teachers Pay Teachers store and pick up the Catastrophic Catapult STEM Challenge. This packet has worksheets guiding your students through the engineering process as well as a full lesson plan aligned to the Australian Curriculum!

The 5 Problems with Group Work in the Classroom (and how to fix them!)

When it comes to group work, there tends to be a few things that inevitably happen in every classroom:

1. There's that one student who doesn't find a group on their own, so you end up having to pick one for them.
2. There's a student or two who slack off letting everyone else do the work then taking credit for it.
3. Someone tries to 'lead' the group, with potentially catastrophic results.
4. That one group of students who actually work well together finishes way before everyone else.
5. There's a group full of students who all slack off and view group work as a time to chat in class.

Well, I'm not sure I can solve all of those problems, but bare with me while I give it a shot!

1. The student who doesn't find their own group

When a student doesn't find their own group, it's important to figure out why. Sometimes its a case of not having many friends in the class, sometimes it's the shyness factor, and sometimes it's the thought of "if I don't have a group I won't have to do it". Yes, this isn't an exhaustive list, but it does cover some of the more common reasons students won't find a group. 

How to combat the issue? After finding out why they haven't found a group, one option would be to ask the problem student who they would like to work with. By doing this, you are still giving them the choice, however, then you can help bridge the friendship or shyness factor, if they don't know who they want to work with that's when you assign them to a group at 'random'. The reason I say random in quotation marks, is that one thing I've found useful, mostly in 4th grade and above, is before class I reach out to one or two students who I know are friendly and responsible and I ask if they would like to be 'group buddies'. A group buddy is someone who I know will help try and make sure any last minute additions to the group feel involved, rather than plopping the student in a group of kids who are all friends and all want to do things their way and will leave the extra student out.

The other option is to pick the groups ahead of time, whether that's by using some crazy algorithmic calculations to try and figure out who will work best with each other and hopefully have a level playing field or by pulling names out of a hat, picking the groups for them is a surefire way to avoid any one student not having a group. The downside to this is that you are taking control away from the students, which isn't always the best idea. Yes in lower grades students aren't necessarily 'ready' socially to pick their own groups, so it's not a problem, but by the time a student hits 3rd or 4th grade they are often itching to get a chance to work with their friends! 

2. The slacker students

I don't know if you remember doing group work in school, but did you ever have a group where you felt like you had to do all the work? That group probably had some 'slacker' students, aka the students who are perfectly capable of doing the work but know that the other people in the group will pick up the slack if they just do that one little thing. When it comes to engaging these students, one thing I do in the STEM classroom is assign each student a job to do. I actually have a freebie up in my TPT store with some role descriptions to use when doing STEM challenges, click the image to head over and download it for your classroom!

But outside of the STEM classroom, the same concept applies. Giving students a specific role to fulfill gives them a sense of purpose, and by instructing them that other students can help with their job, but are not allowed to do it for them will help students stay on track. Here are a few examples of jobs that could apply to some projects: 

• Researcher - takes charge of researching the information
• Project Manager - takes notes of what gets done at each meeting and works out what needs to be done to meet the deadline
• Writer - writes any reports that need to be done
• Presenter - organises speeches and powerpoints for presentations & gives the presentation
• Designer - Designs any posters or power points that need to be made

The list goes on! Students can have multiple roles each and more than one student can be assigned to any given role, but by knowing which 'hat' each of them is wearing, they should be able to be a little more productive in group work time.

3. The cataclysmic leader

There is a Ronald Regan quote that says something along the lines of 'the best leaders don't necessarily do the best things, but rather inspire others to do great things' The cataclysmic leader tends to try and do the best things, instead of inspiring group members to do their best. When it comes to solving this, I look once again to giving students roles. In this case, the roles mean that the student who wants to take the lead has more of a boundary around what they can and can't do, and the other students also are aware of their role and can take the lead in their area rather than having one student saying what needs to be done & how for every aspect of the project.

4. The early finisher group

Now this one relates mostly to STEM challenges, sometimes there's a group who finishes the main part of the project way before everyone else. If I can anticipate which groups are going to finish faster, I start them off with an extra challenge, such as getting them to do a mock costing or sustainability review (there will be worksheets for these activities included in my upcoming buoyancy STEM challenge!). But sometimes students surprise you, so I like to make sure I give them a challenge extension, which generally involves going back to their evaluations and seeing if they can make any of the changes they suggested in ways to improve their design. The great thing about STEM is that it's all about being innovative, and innovation is never done.

5. The slacker group

Often this group is all friends and they view group work time as a chance to goof off and chat, rather than actually get any learning done. This is one of the biggest challenges to conquer because they tend to feed off one another, so when one starts chatting, they all go! But its not impossible to conquer. You could go with setting groups for the whole class rather than letting them choose to work with their friends, or you could opt to check in on them more frequently and make sure they're staying on task, or perhaps give an incentive such as extra free time for the group that works best together. Often the slacker group is interested in the task, but just isn't the best mix of students to actually get things done.

So thats the 5 problems with group work in the classroom, I hope I've given you some ideas on how you can improve group work so that it goes smoothly for everyone. If you've got any other thoughts on how group work could be improved, please share them in the comment section below so that other teachers can see them and use them in their classrooms!