At-Home STEM Activities: How Many Seeds?
In honor of National Wildflower Week, this week’s Distance Learning offerings are focusing on the plant world.
When fruits and other seed plants reproduce (make more of themselves), a tiny new plant embryo forms inside their seeds. The seed protects the embryo and stores food for it. Seeds are released by the parent plant and dispersed (sent to new places) by wind, water, or animal activity. If the seed lands where the conditions are right, the embryo germinates and grows into a new plant.
In this all-ages activity, we’ll practice our estimating, counting, basic math, and motor skills using the seeds from fresh cherry tomatoes. This activity is modified from a lesson developed by National Agriculture in the Classroom.
graphic courtesy of hyrdroponics.co.uk
Materials
Cherry tomatoes
Paper plates (optional)
Toothpicks (optional)
Paper & writing implement
Procedure
Select several fresh cherry tomatoes
Estimate (make a guess): how many seeds do you think are inside that tomato? Write down your answer.
Have an adult help cut the tomato in half
Squeeze out the squishy tomato interior onto a plate
Count the seeds. Our preferred method is to push them around a paper plate with a toothpick, as rough surface of the plate keeps the seeds from sliding around too much. It can be helpful to place the seeds in groups of five or ten and then count at the end.
Write down the actual number of seeds in this tomato…How close was your estimate?
Repeat the process several more times…Do your estimates become more accurate as you count more tomatoes?
Take it Further
Try calculating the mean (average) number of seeds by adding all of your seed count totals and dividing by the number of tomatoes
Find a live cherry tomato plant (or look at a picture of one) and use multiplication to estimate how many seeds there are in the entire plant (average # of seeds per fruit x number of fruits on the plant)
Try this activity with other fruits. How many seeds do you find in a watermelon, apple, orange, or pomegranate?
Why so Many?
Imagine if each of these seeds grew into an adult tomato plant—the world would be taken over by tomatoes in short order!
Recall from our introduction that fertilized seeds are dispersed via water, wind, and animal activity. But there are many things that can happen to a fertilized seed that prevents it from growing to maturity. A seed in the wild could be crushed and eaten, could land on a concrete surface with no soil to put down roots, or could end up in a location without enough water or sunlight to grow.
These cherry tomatoes produce a large number of seeds as a way of making sure that at least some of them live on to become full-grown plants.
image credit: gardeningknowhow.com
