Using potatoes for science experiments can be fun and easy. Potatoes can be bought from the grocery store and are inexpensive for lots of science fun. Since the potatoes can be a little dirty, it is a good idea to wash the potatoes and your hands before you get started. For these experiments you will using raw potatoes.

Physical Sciences

Potato Clock

Floating Potato

Insulating Potatoes

General Science

Classification of Potato Chips

Potato Time

Potato Clock

Chemistry of the potato- Background questions

• 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 battery) 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.

  Need help getting your clock to run?
  
  Try these web-sites to look for some help:

• CHEMystery- electrochemistry
• Riverdeep- electrochemistry

Thinking about it

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

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Floating Potato

Background Questions

• 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
• food coloring

Procedure

1. Get help from an adult to cut your potato slices out of a raw potato.
2. Fill one of the beakers or glasses about three-fourths full with water and put in a potato slice.
   • What happened?
3. How can you make something else happen in the other two beakers of glasses?
   • Hint: You might want to use your salt or sugar!
4. 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

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

Extension

• Take a little bit of water and add a drop of food coloring.
• Very carefully, so that it doesn't mix, add that water to the top of the beaker or glass with the potato that is floating.
  • What happened?
  • What does that tell you about the two kinds of water in the beaker or glass?

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Insulating Potatoes

Background Questions?

• Why do hot things cool off?
• Why do cool things warm up?
• 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: some suggestions (but don't limit yourself to these!)
  • aluminum foil
  • paper towel
  • saran wrap
  • cloth napkin

Procedure

Your goal is to find out which material will keep a hot potato warm the longest.

1. 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!
2. Get 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.
3. When the potatoes are hot, immediately wrap all of them. Wrap each in a different material. You may want to leave one uncovered.
4. Record the temperature of each potato as you wrap it.
5. Check the temperature of the potatoes several times at equal time intervals until they have all cooled off.

Thinking about it

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

Extension

• Repeat this experiment except start with a cold can of pop.
• Does this change the results?

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Classification of Potato Chips

Background Questions

• What are some common classifcation schemes?
• Why would you want to classify objects?
• WHat is a dichotomus key?

Materials

• Lots of different kinds of potato chips!
• Equal number of bowls or plates as kinds of chips.

Procedure

Your goal is to seperate the all the different kinds of potato chips into small homogenous groups.

1. Put samples of all the different kinds of chips in a bowl or plate.
2. Put all the sample of chips together on a table or other large clean area.
3. Begin asking yes or no type questions that seperate the chips into two groups.
4. Continue asking questions and separating the chips until it is not resonable to separate them any further.
5. Write out your system and see if it makes sense to someone else.
6. Eat the chips! (if you kept them clean!)

Thinking about it

• If someone knew what kind of chip they wanted, could they use your key to find a type of chip that they like?
• What other things could you classify this way?
• What things in science are classified this way?

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Potato Time

Background Questions

• Why do people keep time?
• How long have people been keeping time?
• Are there different calendars than the one you are used to?
• Who are the Incas?
• How did the Incas keep time?

Materials

• Potatoes
• Pot
• Water
• Hot plate or stove

Procedure

Your goal is to come up with a system for keeping time based on potatoes.

1. With the help of an adult, carefuly boil several potatoes. Try to find an average time for how long it takes to cook a potato.
2. Create a time system based on your average time to cook a potato.

Thinking about it

Answer the following based on your time system.

• How long is an episode of "Friends" in potato time?
• How long is a week?
• How long is a month?
• How old are you in your potato system?
• Does your system of potato time seems like a good system to use?
• Do you like your system or the traditional time better?
• What are some advantages/disadvantages of each system?
• What other things could you base a time system on?

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