Build Mechanic Toys and Understand Energy Transfer

We have to eat every day to get enough energy. But what is energy, really? We can see energy manifest and move from one form to another, but it isn’t easy to explain what energy really is. Mechanical toys are a great way of introducing the concept of energy. Here are two you can build at home:

Moving muffin animals

These moving muffin animals are awfully cute. They can also teach us a lot about energy and forces.

Equipment

• Large paper muffin cups
• Strong tape
• Bottle caps from soda bottles
• 1 rubber band
• BBQ skewers or another thin stick cut into pieces of about 8 cm
• Scissors and an awl
• Markers for drawing faces on the muffin animals
• Gift bands, pipe-cleaners, feathers, or other decorative elements

Instructions

1. Cut off the plastic band at the bottom of the bottle caps so that the edges are straight. Use the awl to poke a hole in both bottle caps and thread the rubber band through both holes so that the hollow part of the caps face one another. The holes have to be large enough to fit the rubber band. Let the band lie in a loop through one cap and adhere the band that pokes out of the other cap to the cap with tape. Tape the caps together and thread a skewer through the loop.
2. Test to see if the engine works by spinning the skewer 3-5 times and place the caps onto a flat surface before you let go. It’s OK if the skewer touches the floor as it rolls away. If it moves slowly, it might be because the rubber band is either too tight or too loose
3. Make a muffin animal from a muffin cup. Cut out a small piece in the back for the skewer
4. Wind up the toy, place the muffin animal on top and let go. Does it move?

Make a swing

Equipment

• Glue gun
• Scissors
• Tape
• Awl
• 7 skewers small enough for a straw to fit on the outside
• 6 straws
• Paint and paint brushes
• Other decorative items

Instructions

1. Make two pairs of supporting legs for your swingset by using skewers. Cut off the pointy end with scissors. Make sure that the skewers are about the same length, 20-25 cm. Use the glue gun to adhere the skewers together in one end so that they form the shape of an A. One skewer should cover the other so that they form a little cross
2. Cut a skewer so that it measures about 10 cm. Use this to stabilize the swingset by gluing it horisontally to the legs. Make two of these
3. Make the swings while the glue dries. You need 3 straws for each swing
4. Bend the straws and cut off 1.5 cm off the short end. Thread the short end through the other short end and tape the ends together so that they form a U-shape. Adjust the lenght of the swings to the supporting legs so that it can easily swing back and forth
5. Cut off 1-2 cm off each side of the long ends of the straws, making an opening, and glue them to a new piece of straw that is slightly wider than the seat
6. Thread the swings onto a new skewer with the sharp end cut off and glue the stick to the tops of the A-shaped supporting legs
7. Glue another supporting skewer onto each side of the swingset, so that it is stable
8. Paint and decorate the swingset once the glue has dried

What happens?

These toys are called mechanical toys because they can move. The field of mechanics is all about movement. There is a connection between movement, forces, and energy. Forces are at play once something starts to move. When a force pushes or pulls something, energy makes it happen.

When you load the muffin animal by winding the band, energy is transferred from your muscles to the rubber band. Energy is released when you let go of the band and transferred to the wheels which start to spin so that the muffin animal moves forward. When you push the swing with your finger, energy is transferred from your muscles to the swing. Your muscles get energy from the food you eat.