3 crazy kitchen experiments

Published on September 21st, 2012
3 crazy kitchen experiments

You don’t need a fancy lab to perform awesome science experiments. Don’t believe us? Try these out…

1. Make plastic out of milk

WHAT YOU NEED:

  • 600ml milk
  • 20-30ml white vinegar
  • saucepan
  • wooden spoon
  • sieve
  • plastic or rubber gloves
  • water
  • cookie moulds, paint and a paintbrush (optional)

WHAT TO DO:

  1. Pour the milk into the saucepan and heat on the stove until it starts to simmer (don’t let it boil – this will destroy the protein that forms the plastic)
  2. Add the vinegar to the milk and stir until lumps start to form.
  3. Leave to cool down.
  4. Pour through the sieve to collect the lumps, and throw away the liquid.
  5. Put on your gloves and wash the lumps off with water.
  6. Knead the lumps into a single mass and mould into any shape you like.
  7. Leave somewhere dry for a day or two, so the plastic can harden.
  8. Decorate with paint if you’re feeling creative.

WHY IT WORKS:
The acetic acid in the vinegar combined with the heat from the stove causes a protein called casein to precipitate (solidify) out of the milk. Casein isn’t a genuine plastic molecule, but it behaves a lot like it because it has a similar structure. Real plastics contain long-chain molecules called polymers, which tangle together to make plastic so strong.

2. Squeeze an egg into a bottle… without breaking it

WHAT YOU NEED:

  • a peeled hard-boiled egg
  • a glass bottle with a neck slightly smaller than the egg’s circumference (a 250ml Coke bottle is a bit too small)
  • a box of matches

WHAT TO DO:

  1. Light two or three matches and drop them into the bottle (still lit). Tip: do this as quickly as possible. (But remember to be careful!)
  2. While the matches are still burning, place the egg on top of the bottle neck with the narrow end pointing down.
  3. The egg should get sucked into the bottle. If it gets stuck, try working faster or adding an extra match.

WHY IT WORKS:
The flames consume oxygen, decreasing the air pressure inside the bottle so the higher external air pressure pushes the egg into the bottle.

3. Extract DNA from a banana

WHAT YOU NEED:

  • Half a banana
  • 100ml water
  • pinch of salt
  • a coffee filter
  • 2 clear plastic cups
  • dishwashing liquid
  • 5ml pineapple juice
  • 30ml surgical spirits or rubbing alcohol
  • a fork or masher
  • a toothpick
  • a funnel (optional)

WHAT TO DO:

  1. Pour the water into one of the cups and dissolve the pinch of salt.
  2. Using the fork or masher, mash the banana in the salt solution. Mash it well so there aren’t lots of lumps.
  3. Pour the mixture through the coffee filter and into the second cup. A funnel might make this step easier.
  4. Add a few drops of dishwashing liquid and swirl – don’t shake!
  5. Leave to stand for 5-10 minutes.
  6. Add 1-2ml of pineapple juice.
  7. Slowly add surgical spirits or rubbing alcohol – add enough to double the total volume of your mixture.
  8. You should see stringy, white stuff at the bottom of the alcohol layer. That’s the banana’s DNA! Remove it by winding it onto the toothpick.

WHY IT WORKS:
Mashing the banana breaks the cell walls, while the alkaline detergent in the dishwashing liquid penetrates the cell membranes so the DNA can spill out of the cell nuclei. The salt helps the DNA to solidify, and the pineapple juice contains an enzyme that breaks up the proteins that normally keep DNA tightly wound. The alcohol separates the unraveled DNA from the proteins, because the DNA settles in the less dense alcohol layer, while the proteins prefer to settle in the water.


The above three smart experiments were brought to you by 3M, a company that uses curiosity and creativity to solve problems around the world every day. Click here to read more about this awesome, innovative company.

 

Credit: image from Flickr/carbonated