1. Jonathan is a newly recruited lab technician at a school laboratory.
A batch of cells in the school laboratory needs to be kept at 15 C for a particular experiment to be performed. However, the equipment used to maintain the temperature of the cells has stopped working.

2. Therefore, the container of cells will be placed
into an insulated beaker filled with water at
15 C. Jonathan has been tasked to prepare
the beaker of water.
Jonathan knows that by mixing ice and water
in certain proportions, he will be able to get
the water at the required temperature.

3. If I put too much ice, the water will be too cold.
Jonathan thought…
But if I put too little ice, the water will be too warm for the cell samples!
If I put too much ice, the water will be too cold.

4. Your challenge for the day!
Suggest and explain how much water and how much ice Jonathan should mix.