Photo credit: Cate Storymoon via VisualHunt / CC BY-SA

Inside: What makes things alive?  Most often that is obvious. Sometimes it is not.  Try an easy experiment to investigate the characteristics of living things.


What Makes Things Alive?

It is usually a simple task to figure out if something is alive or not living. Click To Tweet Most kids look at a rock and immediately understand it is not living.  At the same time, they look at a puppy and intuitively know it is alive.


But what characteristics determine whether or not something is alive?  Ask your students or kids.  They will give you many ideas of what makes things alive.

Most children will relate “what is alive” to their own experience:

  • living things have eyes;
  • they hear;
  • if its alive it speaks;
  • living things breath;
  • they move.

Not all things that exist on Earth are so easy to classify.  Therefore, it is an important concept in the life sciences to have a very specific set of criteria to determine whether something is living or non-living. Here is an activity you can do at home or in the classroom to determine if something is alive. Click To Tweet  A link is provided at the bottom of the post where you can download a pdf copy of the worksheet for this activity.

What You Need

activity worksheet pencil/pen
 two identical glass cups/beakers measuring cup
yeast sand
china marker or masking tape sugary liquid (apple juice, sugar water)




A dead thing can go with the stream, but only a living thing can go against it. — G. K. Chesterton English Critic

What You Do

Tell the kids you will be examining two substances-yeast and sand- to study characteristics of living things.

  1. Have the kids brainstorm what makes things alive.  Have them record class responses on the worksheet in Table 1.
  2. Label one glass A and the other B.
  3. Add 1 Tb of yeast to glass A .
  4. Add 1 Tb of sand to glass B.
  5. Examine the contents of each beaker and complete Table 2.
  6. Have the students predict what will happen in each glass when your sugary liquid is added.  Have them record their response in Table 3 of the worksheet.
  7. Add 50 mL or 2 Tb of the sugary liquid to each beaker.  Have students watch what happens in each beaker.  Have them record their observations in Table 4 of the worksheet.

Discuss What Makes Things Alive

Discuss the questions listed under “Conclusions” on the worksheet.  Fill out answers on the sheet as a class or have older students go back and answer each question.  The questions are as follows:

  1. What similarities and differences did you notice between yeast and sand in Step 5?
  2. In Step 7, what did you observe in each beaker?  Was your prediction accurate?
  3. What do you think happened in each beaker?  [Hint:  Go back to Table 1 where you listed your ideas about what makes something alive].
  4. Why was it important to use equal amounts of yeast and sand and an equal amount of sugary liquid in each beaker?
  5. How has this activity helped you understand the differences between living and non-living things?  What new questions about living and non-living things do  you have after performing this activity?

Wrapping Up What We Now Know Makes Things Alive

In Table 5, write 5 to 7 criteria you now feel are most important to determine whether something is living or non-living.

Get Your "What Makes Things Alive: Easy Experiment Worksheet" Here

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