Science experiments with potatoes

My friends and I were talking about how much fun science is and I got to thinking my readers may enjoy trying a science experiment or two. The following are three of my favorites. Having fun and learning at the same time is the best!

Insulating potato

Questions to ask before the experiment begins:

  • Why do hot things cool off?
  • Why do cool things warm?
  • How can you slow the cooling or warming process?
  • Can you stop the cooling or warming process?
  • What is an insulator?
  • What types of things are good insulators?
  • What is a good way to organize data that will be collected in this lab?

Materials

  • Potatoes
  • Thermometer

Insulating materials:

  • Aluminum foil
  • Saran wrap
  • Cloth napkin

Procedure
Your goal is to find out which material will keep a hot potato warm the longest.
If you are using thermometers or temperature probes, carefully poke the potatoes with a big enough hole that a thermometer will fit snugly down into the middle of the potato. You can do this without a thermometer if you do them all at once and use your sense of touch to determine which is the warmest.

Ask an adult to help you heat some potatoes in the oven or microwave. You can either do them one at a time or all at once depending if you have more that one thermometer.

When the potatoes are hot, immediately wrap all of them. Wrap each in a different material and leave one uncovered.
√Record the temperature of each potato as you wrap it.
√Check the temperature of the potatoes several times at equal time intervals until they have all cooled off.

  1. What type of material kept the potato the warmest?
  2. Is there any relationship between the materials that worked the best?
  3. How can this help you to keep potatoes warm the next time you want to serve them at a meal?

Potato Clock

Questions to ask before the experiment begins:

  • What is a potato made of?
  • What is electrochemistry?
  • What is a chemical cell?

Materials

  • 2 raw potatoes
  • Heavy gauge copper wire
  • 2 large steel nails
  • Various pieces of connecting wire (with alligator clips if possible)
  • Small (single LCD display digital clock

Procedure
√You will be powering the clock using the potatoes as batteries.
√Try different ways of hooking up the potatoes to each other and the clock.
√Keep track of what combinations produce some voltage and what ones don’t work.
√Think about how a battery works when you try to hook up your potato.

  1. How long did your potato powered clock run?
  2. Could you use more than two potatoes?
  3. How would it change if you used more than two potatoes?
  4. Can you use other fruit/vegetables to make the clock run?
  5. What fruit or vegetable or combination makes the clock run the longest?

Floating potato
Questions to ask before the experiment:

  • Why do some things float?
  • What is density and does it have anything to do with controlling what floats?
  • What is solubility?
  • How soluble are salt or sugar in water?

Materials
√Water
√Potato slices, 3 about 1 inch slices
√3 beakers or glasses, tall and skinny will be the most dramatic
√Stir rod or spoon
√Salt or sugar

Procedures

  • Your goal is to make one of the potato slices sink, one of the slices float, and one of the slices be suspended right in the middle of the beaker.
  • Ask an adult to help cut your potato slices out of a raw potato then fill one of the beakers or glasses about three-fourths full with water and put in a potato slice.

What happened?
How can you make something else happen in the other two beakers of glasses?

Hint: You might want to use your salt or sugar.

Make one of the slices float and one of them be suspended half way down the beaker of glass that you are using.

Thinking about it

  1. What was different about the three beakers of glasses that allowed the potatoes to float or sink?
  2. Why didn’t the water spill out the top of the beaker or glass when you added the sugar and salt?
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