Simple seesaws
You’ll need
- 21 ropes for lashings and guys
- 4 stakes to anchor project
- 1 round spar for roller
- 4 longer spars for A-frames
- 2 spars for A-frame bases
- 5 small spars for connectors
- 1 sturdy plank as seesaw seat
- 2 tires to cushion landing
Before you begin
- Before building your seesaw, check that your ropes and spars are in good condition and not likely to break whilst it is in use.
- Try to scale the project with those building it. Nothing should be too heavy for one person to lift and use safely.
- Make sure everyone has sturdy shoes on and that the ground you’re building your seesaw on is steady, level and presents no other hazards.
- The design of this project is simple, but it needs tight and precise lashings. Everyone will need to work together to make sure everything’s level and to keep checking that the balance of the seesaw is correct.
- Use the attached assembly instructions for a visual explanation of the project.
Ready set seesaw
- Start making two A-frames. Take two similar-length spars and tie a sheer lashing on one end. This will be the top of one frame.
- Pull the two spars apart at the other end. Lash a third spar across the base of the ‘A’ to make the support. Use a diagonal or square lashing.
It’s important to make sure the lashings are firm so that they do not come undone whilst the table is being used. Keep the rope tight as you create the lashing for the best results. Help from a friend always makes this easier.
- Make a second A-frame in the same way and check that both are the same size and shape by standing them up, side by side
- Select a spar for your roller The width of this spar is how far apart your A-frames will be.
The roller should overhang on each side enough that it won’t slip out when the seesaw is used.
- Take the roller out once you have the size it needs to be as it will be difficult to make the lashings with the roller in place.
- Use a square lashing to fix the roller in position using four shorter spars and use a fifth to connect the tops of both A frames together.
- Lash the bottom ones first, this means that you can lay the roller in place on the bottom set to check the height again before fixing it in place.
These lashings will need to be tight and the supports will need to sit level for the seesaw to work properly. The roller should be held firmly but still turn freely.
The higher your roller sits on the A-frame the steeper the angle of the seesaw, adjust it accordingly so that the roller is roughly waist height to the user.
- Hammer four stakes in the ground at 45-degree angle in a square around where the seesaw will stand. These will help to stop the seesaw tipping over so will need to be firm and the guy ropes securing them should be tied tightly. Using a round turn and two half hitches but with more half hitches is one good way to do this.
Don’t use tent pegs for this, as they won’t be strong enough.
- Square lash a plank firmly to the centre of the roller. Make sure you have the same length of plank on both sides of the seesaw.
- Lay the two tyres beneath either end of the plank, to cushion the landing when either end comes down.
Remind your riders to not kick off from the ground when using your finished seesaw, or to try and unbalance the other rider, as this may damage something.
- Remember to explore the science behind seesaws too with the information in the drop-down below.
- Once you’ve built your seesaw, explain that the seesaw is a kind of lever.
- A lever is one of the simplest mechanisms. It uses a fulcrum to pivot between a load and a downward force to lift the load. When the loads are the same and the fulcrum is in the middle, the seesaw balances. The fulcrum on the seesaw is the roller.
- Ask the group to see what happens when you unbalance the load. For instance, what if you sat two people on one side and one on the other?
- Try adjusting the position of the plank, so that the middle of the plank is no longer on the roller. Without a load, this will cause the longer end to touch the ground, but with the right load on the shorter side, the seesaw will again balance out.
- Remember that when using a lever like the seesaw, you need to keep the balance in mind. Suddenly putting pressure on or taking it off by letting go will cause the load to come crashing down or to jump up. This could hurt someone or damage something. For this reason, lower and raise the load carefully and if working with others, keep talking to them to let them know what you’re going to do next. Never let go without warning and always be aware of where your feet are.
- What the lever is made of is important too. Use materials that you know can take the strain. An old, thin stick might snap and cause the load to come crashing down.
Reflection
This activity demonstrated your pioneering prowess. While the design of the seesaw is simple, the knots and lashings needed to be placed precisely. This meant that you needed to slow down and think carefully before tying them. How many times did you check your lashings were correctly tied and tight enough to hold? Why might this be important, given what you’ve learned about levers and loads, and given the size of the seesaw you’ve built?
Planning ahead can be boring and get in the way of the fun, but taking your time to approach problems properly can mean a greater chance of success. How did everyone do their bit to help make the seesaw come together? This was a chance for everyone to demonstrate their strengths, whether those were knot-tying, instruction-following, project-managing or seesaw-testing.
Safety
All activities must be safely managed. You must complete a thorough risk assessment and take appropriate steps to reduce risk. Use the safety checklist to help you plan and risk assess your activity. Always get approval for the activity, and have suitable supervision and an InTouch process.
- Outdoor activities
You must have permission to use the location. Always check the weather forecast, and inform parents and carers of any change in venue.
- Poles and long objects
Be careful when moving poles or long items. Take care if the ends are sharp. Have appropriate supervision for this activity.
- Heavy and awkward objects
Never lift or move heavy or awkward items alone. Ask for help or, if possible, break them down into smaller parts.
Try making a miniature seesaw first, to get an idea of the design and how it works.
You could add some handles with any leftover or spare rope, so that those riding the seesaw can hold on.
If anyone’s not able to help physically build the seesaw, they should contribute to the effort by checking the design or instructions, directing the builders, checking that lashings are tight enough and by testing the seesaw.
All Scout activities should be inclusive and accessible.
If you enjoyed this project, think about what other things could you build from poles and rope? Why not try a gateway, a bridge or a fairground ride?
Encourage young people with existing pioneering skills to support those less confident and help them learn something new and stick with the project through to the end.