Disappearing Ghosts

Materials Needed:

• Biodegradable packing peanuts (made of corn!)
• Dark colored marker
• Pipette or paintbrush
• Small cup of water
• Tray/plate/cookie sheet

Instructions - Set-up:

• Use your marker to draw ghosty faces on several biodegradable packing peanuts
  • Invite your young scientist(s) to draw some faces, too!
• Place ghosts, small cup of water, and pipette on a tray, plate, or cookie sheet

Instructions - Activity:

• Explain to young scientists that today they are going to make some ghosts disappear!
• Invite them to touch the ghosts and guess what material was used to make them
  • Talk about the texture, the weight, and ask if it reminds them of anything they’ve seen/touched before
• Show them how to use their pipette and tell them to carefully drip some water onto their ghosts
  • What happens?!
    • You can also use a paintbrush to carefully drip water
• Eventually they will notice that their ghosts are shrinking and “disappearing” into a pool of water!
  • Ask them what happened? How do they think that happened? Do they think the ghosts really disappeared? Where did they go?!

The Science:

Although it may have LOOKED like the ghosts were disappearing, they were actually dissolving! The packing peanuts are made of corn, which dissolves in water. If you put a handful of these packing peanuts into a jar of water and shook it, they would completely dissolve--leaving some cloudy white water behind.

Packing peanuts are traditionally made of styrofoam which takes millions of years (we think!) to biodegrade and become dirt in the earth. These packing peanuts biodegrade almost instantly, making them much more environmentally friendly--and they also make an awesome science experiment!

Bonus Activity: Monster Ice!

Can’t get your hands on biodegradable packing peanuts? No worries! Try this fun experiment instead.

Materials Needed:

• Plastic container (freezer safe)
• Water
• Googly eyes or other Halloween trinkets (spider rings, erasers, etc)
• Small cup with warm salt water
• Pipette or paintbrush
• Tray or cookie/baking sheet
• Red & yellow food coloring (optional)

Instructions - Set-up:

• The night before the activity, or several hours before, put water into your plastic container.
  • Add yellow and red food coloring to make orange, if you’d like
  • Put in the googly eyes or other Halloween trinkets
  • Freeze!
• Place plastic container with ice* on a tray with cup of warm salt water & pipette/paintbrush
  • *You might be able to get the ice out of the container, if not--start with the ice still in the container and as young scientists add water & salt, you will easily be able to get the ice out!

Instructions - Activity:

• Invite young scientists into the experiment area
• Ask them what they see!
• Encourage young scientists to use the pipette or paintbrush to drip warm salt water onto the ice and “free” the halloween trinkets
  • Ask: What is happening?
  • Mention that the water is warm and has salt in it--ask how they think this might help to melt the ice
• Continue adding water until the trinkets are unfrozen!

The Science:

• Salt lowers the freezing point of water. Ice melts faster when salt is added as the salt lowers the freezing point of the ice, this is known as freezing point depression. The more salt you add the lower the freezing point.
  • This is why we use salt on roads in the winter to help melt the ice and make them safe!