Halloween is a great time to experiment and dazzle with science!

 

handsArticulated Severed Hand

Want to know how your hand works? You don’t actually have any muscles in your fingers. So how can they move? Make your own moving hand with paper and straws.

 

What You Need

Card stock paper or foam

Pencil

Scissors

Tape

Straws

String

Beads

 

What You Do

  1. Trace your hand on the paper and cut it out.
  2. Feel the bones in your fingers. How many do you feel? (three.
  3. Make lines on your paper hand where the lines on your actual fingers are.
  4. Cut three straw segments for each finger.
  5. Tape the segments on the hand. Make sure you have about ¼ inch of sopace between each straw.
  6. Feel the bones in your hand. How many can you feel? (five?)
  7. Cut five straws and tape them to the hand.
  8. Cut 5 pieces of string 1 foot long each.
  9. Tie the end of each to a bead.
  10. Thread the string through the straws of each finger and hand bone.
  11. Pull on the strings to see your hand move.

What’s Going On?

Hands are amazing! They are brimming with nerves which allow you to feel, blood vessels for bringing in nutrients and taking waste away, and bones.

There are 3 bones in each of your fingers, and 2 in your thumb. These bones are called phalanges. The phalanges connect to 5 bones in the main part of your hand, called metacarpals. Your wrist is made up of 8 bones that work together and connect to the two lower arm bones—the radius and the ulna. Bones are great, but they don’t move on their own.

Muscles are what move bones, and fingers don’t have a single muscle in them!

The muscles that move your fingers and thumb are actually in your forearm. Place your right hand on your arm right below your elbow on your left arm. Waggle your left fingers. Feel the muscles move?

Attached to the end of the muscles are tough string-like tissues called tendons. The muscles in your arm have long tendons that reach from the forearm muscles through the wrist and palm to the fingers and thumb. Like the strings in the straws, the tendons slide though little tunnels. The tunnels are called tendon sheaths and they are stuck to the bones in your fingers and thumb. This keeps all the tendons in place. When the muscles in the forearm contract, they pull on these tendons to move the bones.

hand7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mummified hotdogs

King Tut’s got nothing on you! There’s a science of mummification and it’s all about sucking out the moisture and killing off the little bugs that break tissues down.Make your own mummies by preserving hotdogs with kitchen chemicals.weiners

 

 

What You Need

3 Hot dogs

3 Airtight plastic storage box with lid that is longer, wider, and several centimeters deeper than the hot dog. Or you can use Ziploc baggies

A box of Baking soda

Salt—one whole container

marker

 What You Do

  1. Put one hot dog in each baggie.
  2. Zip one shut and label that baggie “Control”. You won’t mummify this one. You’ll just see what happens to a hot dog when you do nothing and leave it out.
  3. In the next bag pour enough baking soda over the hot dog that it disappears entirely. You want to make sure every part is covered. Zip it shut. Label it “baking soda” .
  4. In the last bag cover the hot dog entirely with salt. Zip it shut and label it salt.
  5. Label all the baggies with the date and set them aside.
  6. Check back on your mummies after two days. What do you notice?
  7. Check back after four days. A week.
  8. How do the mummified hot dogs compare to the untreated one.

Want to take it further?

You’ll need these tools to measure the length, diameter and weight of your hot dog mummy at different stages of the experiment.

Ruler

Piece of string or yarn (at least 10 cm long)

Kitchen scale,

Lab notebook and pencilWhat changes do you see? Which material makes the biggest change? How do your mummies feel? Record your findings in your notebook.mummy

 

 

 

 

 

 

 

Dry Ice Crystal Ball

You can make a great crystal ball bubble with smoke swirling around inside. All you need is a little chemistry!

fortune-teller-crystal-ball

What You Need

Dry ice

Warm water

A bowl with a smooth lip

Bubble solution

A rag

 

What You Do

  1. Fill your bowl ¾ of the way with warm water.
  2. Place a chunk of dry ice in the bowl. (Get a grown up to help and use gloves. This stuff is SUPER cold and can burn fingers. Use a piece of ice about the size of a golfball.)
  3. Dip your rag into the bubble solution and stretch it across the rim of the bowl. Swish the rag across the whole opening of the bowl to create a film.What’s Going on?
  4. As the dry ice sublimates, the carbon dioxide vapor is caught inside the bubble solution. The bubble expands, but the cooled bubble solution does not evaporate quickly so the bubble lasts for a relatively long time.
  5. Dry ice is solid carbon dioxide. It’s COLD! When you add it to water it immediately goes into a gas form. It looks like it is boiling. This is called sublimation.