A Scientific Journey Back in Time

Grade 7 Science Project

During the long lockdown, Grade 7 students worked on a creative task. They had to go back in time to the 19th century and take on the role of Dimitri Mendeleev. He had to convince The National Science Foundation (NSF) in a letter that his periodic table was correct and made sense.

All letters were very creative and had a lot of evidence in support of his genius predictions. Enjoy the example below by Luna:

Dear NSF,

I have been informed that you think my work is not accurate and it does not make much sense, I am writing you this letter to try and convince you that my theory is correct and you should take another look at my periodic table.

For many years, scientists have been trying to find a way to sort the elements, and maybe that has not been possible because they have been looking at it from the wrong perspective. I believe more elements will be discovered and that is why I have blank spaces in the periodic table. 200 years ago, people believed that all the elements that had been discovered but  now we know that was not true. That is the reason they were not able to design a good periodic table. I have ordered the elements in a certain way, so there are gaps in between the elements, thinking that’s where the ones that have not been discovered will go. Our theories always change, because we discover more and more every day.

I have organized the elements by atomic mass. Atomic mass is the weight of an atom in an element. With the way, I organized these elements I can predict the atomic mass of an element, what it looks like, its melting point, and how much a cubic centimeter of it will weigh. And that is all just from where it is located in the periodic table. I have grouped elements, by their physical properties. I found a way to group both atomic masses and physical traits. If you look horizontally at this table, you can see elements that increase by atomic mass. If you look vertically, you can see how elements with similar physical properties are grouped. If you look horizontally, the elements are organized periodically, that is why I am naming this the periodic table.

I started grouping the elements with similar physical traits. With this, I have made 8 groups. After I separated them into groups, I looked at their atomic masses. In the groups, I found elements with similar atomic masses. I then organized the elements by atomic mass horizontally and I saw that the distance of atomic masses between two elements was too big, so I left a space for an element to be added. When I organized them by atomic mass, I kept in mind I wanted them to be grouped with similar physical traits. This where I saw how I was able to organize them so that both of those things were possible. I simply organized them by atomic mass horizontally and I grouped them by physical similarities vertically. These were my results.

In my periodic table, I have left a gap for an element that I have named Eka -aluminium. I have named it that because it is located under Aluminium. Just from where it is located in the periodic table I can tell you all about it. Its atomic mass will be 68. One cubic centimeter of it will weigh about 6 grams. It will be a shiny metal at room temperature and it will be able to conduct heat quite well. The melting point is very low, it is at approximately 30 degrees Celsius. It can be flattened and stretched.

In a couple of years, we will discover a new element and I will have a space left for the element in my periodic table. For many years we have been trying to find a good system and we have not been able to do that, because we thought we had discovered all of them, but I assure you there are more. Mathematically, there must be more. No scientist has ever given you this much detail and is so sure about what he knows, what he is doing, and what he is predicting.

Please give me a chance and in a few years, when more elements will be discovered, you will be glad that you trusted me.


Dmitri Mendeleev



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