Probability of Growth

Hello mathematicians, puzzlers, and other curious people!

Today I\’d like to start a probability measurement experiment that you might also be able to count for science class if you need one. The basic question you\’re going to be asking here is \”what percentage will grow?\” Or, to state it more formally, \”what is the probability that a seed will grow?\”

As you might imagine, this can depend on what kind of seed it is and how the seed is handled.

You will need these supplies:

• Some kind of seeds — 10 of them. (Or a different number if you wish, but starting with 10 makes the percentage calculations easy, so that\’s a \”lazy like a mathematician\” suggestion.)
  • As well as packaged seeds for gardening, you can try foods that are seeds, such as beans and popcorn kernels.
  • You can do this experiment with more than one kind of seeds and compare the results between the two.
• Something for the seeds to grow in, such as dirt or moistened paper towels.

Instead of giving you step-by-step instructions, I\’m leaving it up to you to make some decisions about how to do this experiment, because I don\’t know exactly what you have available. But, that doesn\’t mean you\’re going to just randomly and chaotically throw things together! Remember that the difference between science and goofing around is writing down what you do.

Write down everything you can think of that happened to the seed, between when it was gathered from a plant and when you start the experiment. Then, write down everything you do and see, too!

Here are some examples of procedures you might need to write down:

• If you will use dirt, write down how often you will water it (or how you will decide to at the time like by checking the dirt), and what kind of dirt it is.
• If you will use paper towels, write down your plan for keeping them moist.
• When will you count a seed as having grown? Whether it will be a certain number of leaves, a certain height, or something else that you\’re sure can be counted fairly, make sure you have a plan and any measuring tools you will need. Also, think about how long it might take for the plant to meet your requirement — you will be able to do your calculations sooner by counting a plant as having grown when it has grown five centimeters (about two inches) rather than waiting until it grows to twenty-five centimeters (about ten inches), for example.
• You should also decide and write down how often you\’re going to check to see if the seeds have grown, such as once a day or combining with the watering schedule, and set a particular time at which you plan to conclude that if a seed hasn\’t yet grown, it\’s not going to. Each time you check, you should write down what you see.
• If you want to do anything fancy like add fertilizer, use a grow-light, or measure your soil\’s (or paper towel\’s or ???) temperature or pH at the beginning and end or any other time in the experiment, write down those plans too.

If you have different ideas about which procedure would be best, you can do both and compare the results between the two.

During the experiment, if you make a mistake in your procedure like forgetting to check one day, write down what actually happened. You can try to figure out later whether it made a difference to your results, but above all else you have to be honest. The same thing applies if you have to make a change to your experiment partway through, such as if you had been keeping it inside but your parents or roommate decide it\’s too messy so you have to take it outside.

Before you do anything else, make sure you write down your detailed hypothesis. You can fill in the blanks in \”Under the described conditions, __% of __ seeds will grow\” and add in any details that you want to.

Now let\’s go get some data.

Calc You Later!