This research’s goal is to determine how the elementary schoolstudents’ perception that they receive their education in an elementaryschool is about the amount conservation in the liquids because they arein the concrete operation period. The research has been made with 113students in total who received their education at 1 st , 2 nd , 3 rd and 4 thgrades at an elementary school in Canik in Samsun in the autumn termof 2017-2018 education-training year. Three activities which weredeveloped in order to determine the pre-knowledge of students related tothe amount conservation in the liquids were used to gather the data, itwas shown how the amount conservation is in the practices after thoseactivities. 4 erlenmeyers at the different width and length that includethe same color (yellow) and equal-amount liquid for the 1. activity theflask, graudated cylinder, beaker and erlenmeyer in the different colors(purple, green, orange and blue) and with the equal-amount liquid for the2. activity; 1 beaker and 1 graudated cylinder in the same color (blue)and with the equal-amount liquid for the 3. activity were given. Thestudents were asked to answer the question about which pots’ liquidamount is the most one in all the activities. After the data was collectedthrough the worksheets, it was shown in the practices in all theclassrooms that the liquids gets the shape of pot that they are pouredand there is not any change in the amount, and when the liquid is pouredinto the 1. pot, the amount will be the same one also. As a result of theresearch, it was determined that the students stated for all the activities that the liquid amount will increase as the liquid level in the potincreases. This result shows that the cognitive step related to the amountconversation in the liquids has not developed in the elementary schoolstudents yet.