BHP: Evidence-Based Knowledge & Claim-Testing

I am going to back-track slightly before continuing on with Unit 3: Stars & Elements – I would like to talk more about claim-testing and evidence-based knowledge.

In my last post I mentioned that analyzing how people assess the truth behind their ideas, or claims, might be a bit obtuse of a topic for my young kids. But then I was contacted by a fellow Big History Project teacher who suggested I read this BHP blog post about the Mystery Box.

This simple yet philosophically rich mystery box activity was invented by Scott Henstrand, a teacher in New York, and it perfectly conveys the process scientists/historians use of (1) making a claim; (2) evaluating evidence to support/reject that claim; and (3) updating their claim to reflect this new evidence.

I completely changed my mind about the importance of introducing claim-testing to my kids after reading Scott’s blog post (which, I have to say, is a great example of a “claim” being updated based on new “evidence”).

With not much time on my hands to prepare before breakfast one morning, I grabbed a few empty yogurt containers and created my mystery boxes. This entailed putting one kitchen item into each of three containers and sealing them with lids.

Over breakfast, I chatted with my kids about claim testing. Nothing too big – just a basic introduction to the concept of evaluating the accuracy of ideas based on evidence – and then we set to work.

Each child chose a container – it was their job to determine what was in their “box”. They could use any and all of their senses to do so, and they could consult with one another in order to expand their own perspectives. They could also compare their containers to other items in our house. The only rule was that they could not open their box.

Each child had a copy of Scott Henstrand’s Mystery Box Observation Worksheet (just scroll down through the blog post I linked to above to find it) where they made a claim, such as “there is an apple in the box”, and then tested it, “when I shake my box it feels like an apple is rolling around inside”.

They shook their containers and listened to the sounds their items made; they felt how heavy their containers were; they attempted to smell their containers; they found empty yogurt containers in the kitchen and, adding items one-by-one, shook them, dropped them, and otherwise compared them to their own; they passed them to each other and asked for insights.

It was slightly maddening to not be able to just pop off the container lids and look inside, but we discussed how this is the process by which many scientists make discoveries – they cannot go directly to the source of something in order to confirm their theories (astronomers can’t fly out to the stars, historians can’t travel back through time). Instead, they can make a claim about something happened, test that claim based on evidence, and update their claim to support the new evidence.

My kids did great with their claims and tests – one had an orange in their container, one had a cloth napkin, and another had a bag clip. They concluded (before pulling off the lids) that they had an apple, kitchen towel, and small plastic item, respectively.

In Scott’s version of this activity, however, the box is never opened! This is a more accurate portrayal of how some theories, like the Big Bang (as he mentions in his blog post) can never truly be tested. For my young kids, especially my three year old, it was hard enough to hold the box without opening it for five minutes, so I let them look inside at the end. When they are older and we repeat the Big History Project more in depth, this is an activity that we will definitely return to … and we will keep the boxes closed 🙂

They had so much fun that they have asked to do the Mystery Box activity again and again.

In another round, one container was filled with water. The child who had this “box” immediately claimed it was water, and we had fun questioning that claim:  Even if it sounds and moves like water, couldn’t it be another liquid? Even though you see drops dripping down the side and they look like water, couldn’t they be something else, perhaps something toxic? How can you really know it is water?

Any conversation that turns philosophical and incites questioning is a great conversation in my book, and this simple activity led us down many exciting rabbit holes. I hope you enjoy it as much as we did, and a big thanks to Scott Henstrand for sharing this idea!



  1. Really enjoying this series. I’m wondering if you continued with BHP, and, if so, whether you are planning to post what you did. I think I am going to start BHP with my children (ages 7 and 4) and would love more inspiration/ideas for adapting it for young children.

    • Hi Jennifer, thank you so much for your feedback! I’m glad that you have enjoyed the series so far, and yes, I have continued to teach BHP to my kids and I have posts on Units 3 and 4 in the works. Please stay tuned!

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