We know how much you love your Boxed box. We’ve seen you turn your boxes into Halloween costumes, gardens, and castles. Now, we’re making it easy for you to spend time creating AND learning by partnering with our friends at KiwiCo. KiwiCo delivers hands-on activities that help kids build their problem-solving skills and creative confidence. Learn more about an exclusive offer for Boxed customers here.
At Boxed, our bulk is our strength. Today, we’re going to teach you how to turn your #BoxedBox into a muscle machine that demonstrates how contracting or relaxing your biceps and triceps moves your arm — nifty, right? This is a really fun activity to do with kids during the holidays. Don’t forget to save your Boxed box from your Thanksgiving stock up!
While there are lots of muscles that power movement in your arm, the bicep and tricep muscles are two of the most noticeable, partly because of how big they get on some body builders. 💪 These paired muscles flex and extend the elbow joint, allowing you to bring a fork to your mouth or throw a frisbee (or lift a full box of snacks!). When one flexes, the other relaxes.
In this muscle machine, you’ll be mimicking the action of a muscle by pulling a string. This is actually pretty similar to how your muscles work. Muscles are made up of long fibers of cells, kind of like bundles of string. The cells in a relaxed muscle fiber are long and skinny. When a muscle flexes, the cells yank themselves together, going from long and skinny to short and round. This shortens the muscle fiber too, so anything the muscle fiber is attached to will move in the direction of its contraction. The string mirrors this by changing its length when you pull on it.
- printable template (included below)
- double-sided tape
- brads (8)
- bobbins (4)
- zip ties (2)
- glass or plastic bottle
- water (optional)
Step 1: Gather your materials!
Step 2: Print the printable, cut out the pieces, and set the bicep and tricep pieces aside.
Step 3: Trace the printable pieces (except for the bicep and tricep) onto a piece of cardboard from the box and use the pushpin to mark where the holes are.
Tip: The holes are indicated by the small marks on the printable.
Step 4: Cut out the cardboard pieces.
Step 5: Use double-sided tape to stick the bicep and tricep pieces onto the oval-shaped cardboard cutout. Then, widen each of the marked holes with a brad. The brads should easily fit into each hole.
Step 6: Fasten the bobbins to the cardboard pieces with the brads as pictured.
Step 7: Use another brad to connect the bicep and shoulder cardboard pieces as pictured.
Step 8: Fasten two brads to the forearm cardboard piece as pictured.
Step 9: Cut two pieces of string about 18” in length and tie a loop-knot on one end of each string. Then, wrap the loop around the two brads on the forearm.
Step 10: Connect the forearm and bicep cardboard pieces as pictured.
Step 11: Thread the string onto the bobbins as follows: clockwise for the top string (bicep) and counterclockwise for the bottom string (tricep).
Step 12: Thread zip ties through the remaining marked holes on the shoulder as pictured.
Step 13: Secure the cardboard arm to the bottle with the zip ties. Then, start experimenting!
Step 14: To move the arm up and contract the bicep muscle, pull on the top string. To move the arm down and contract the tricep muscle, pull on the bottom string.
When you have gotten a hang of how the muscles work, see if you can pick something up!
There are way more muscles involved in moving your arm than just your biceps and triceps. Extensor and flexor muscles run through your forearm to move your wrist around. The deltoids on top of your shoulder, the pectoralis major on the front of your chest, and the latissimus dorsi on your back all help move your shoulder around. Your body has 650 muscles!
Many muscle groups work in pairs like the bicep and tricep. Flexing one will move a limb one way, and flexing the other will move it back. Which other muscle pairs can you find?
Some to check out:
- Flexing your foot up and down
- Bending and unbending your knee
- Moving your leg away from your body and back
- Bending forward and backward